JANUARY 30, 1985

THE

NAUTILUS

ISSN 0028-1344

Vol. 99

No. 1

A quarterly

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malacology and

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conchologists

Founded 1889 by Henry A. Pilsbry. Continued by H. Burrington Baker.

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The American Museum of Natural History

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Museum of Comparative Zoology

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Dr. Donald R. Moore

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Dr. Joseph Rosewater

Division of Mollusks

U.S. National Museum

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Field Museum of Natural History

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Dr. David H. Stansbery

Museum of Zoology

The Ohio State University

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Dr. Ruth D. Turner

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Museum of Comparative Zoology

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THE

NAUTILUS

Volume 99, number 1 — January 30, 1985

ISSN 0028-1344

CONTENTS

Richard H. Bailey

Human Modification of Molluscan Habitats in Little Creek Estuary, Virginia.

Mark E. Gordon

Mollusca of Frog Bayou, Arkansas

Anthony D'Attilio and Barbara W. Myers

A New Species of Pygmaepterys Vokes from the Western Pacific

(Gastropoda: Muricidae) 9

William K. Emerson

Murex hamatus Hinds, 1844, a Living West American Species Assigned to

the Neogene Paciphile Genus, Pterorytis Conrad (Gastropoda: Muricidae) 14

Clement L. Counts, III

Corbicula Jluminea (Bivalvia: Corbiculidae) in the State of Washington

in 1937, and in Utah in 1978 18

Raymond W. Neck

Tropical Veronicellid, Laevicaulis alte (Ferussac), Established in Southern Texas 19

L. A. J. Al-Hassan and Z. I. Al-Hasani

New Records of Marine Mollusca from Khor Abdullah, Iraq 20

Paul E. Fell and John H. Williams

Distribution of the Snail, Melampus bidentatus. and the Mussel, Geukensia demissa,

Along the Pataguanset Estuary (Connecticut) in Relation to Salinity and

Other Tidal Marsh Invertebrates 21

William K. Emerson

Two New Species of Lyria from the Western Atlantic (Gastropoda: Volutidae) 28

News ii Meeting ii

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1985 AMU Meeting

The American Malacological Union will hold

its annual meeting on the campus of the Univer-

sity of Rhode Island on July 29- August 3, 1985.

Three symposia will be presented: one on mol-

luscan egg capsules, organized by Jan Pechenik;

a second on molluscan radulae, organized by

Robert Bullock and Carole Hickman; and a third

on ecology of freshwater molluscs, organized by

Eileen Jokinen. There will also be contributed

papers, a poster session, marine and freshwater

field trips, workshops, an auction, exhibits and

commercial sales of items of interest, and a New

England clam bake. A program to honor junior

malacologists will open the meeting. The Boston

Malacological Club is planning special events in

commemoration of its 75th anniversary. For

further information please contact Dr. M. R.

Carriker, College of Marine Studies, University

of Delaware, Lewes, DE 19958.

ii

Vol. 99(1)

January 30, 1985

THE NAUTILUS

HUMAN MODIFICATION OF MOLLUSCAN HABITATS IN

LITTLE CREEK ESTUARY, VIRGINIA

Richard H. Bailey

Department of Earth Sciences

Northeastern University

Boston, Massachusetts 02115

ABSTRACT

Mollusks of Little Creek estuary in southeastern Virginia may be grouped into

five assemblages indicative of the following benthic habitats: 1) fringe and em-

bayed Spartina marsh, 2) solid substrata (rock, pilings, shell), 3) intertidal muddy

sand, 4) subtidal muddy sand, and 5) black organic mud.

Human activities in the estuary such as dredging, stabilizing shorelines, land-

filling, disposing of dredged spoil, and introducing foreign solid substrata have

modified habitats and/or sediment character thus altering the distribution of

molluscan assemblages.

Human activities within and around shallow

estuaries of the southeastern U.S. may have

substantial effects on the distribution and com-

position of bottom sediments. Substratum type

exerts a strong control on benthic molluscan

assemblages (Bird, 1970; Johnson, 1972). This

paper correlates particular human activities

with resultant changes in substratum and mol-

luscan assemblage distribution in the western

segment of Little Creek estuary.

Little Creek is typical of the numerous small

estuarine systems in heavily urbanized areas of

southeastern Virginia (Fig. 1). It is somewhat

unusual in that it was formerly a freshwater

lake (Pretty Lake) impounded behind the ocean

FIG. 1. Map of mouth of Chesapeake Bay showing location

of Little Creek estuary and area enlarged in Figure 2.

view barrier-bar and dune complex. When the

bar and dunes were breached by dredging,

Pretty Lake became a broad shallow estuary.

East of the bridge where U.S. route 60 crosses

Little Creek, commercial development, mainly

marinas, and the U.S. Naval Amphibious Base

dominate the shoreline. West of the U.S. 60

bridge the original basin configuration has been

less modified and the shoreline largely devoted

to residential development. The western branch

of Little Creek has about 21 km of shoreline of

which about 26 percent (5.3 km) is narrow

muddy beach, 51 percent (10.9 km) is fringe

marsh, 18 percent (3.7 km) is embayed marsh,

and 5 percent (1.0 km) is permanently stabilized

by bulkheads and rip-rap (Owen and others,

1976). The preceding figures include a small

amount of shoreline east of the bridge. Water

depths over most of the western segment of Lit-

tle Creek range from 0.5 to 1.5 m (MLW). Max-

imum depths of 1.7 to 2.5 m (MLW) were meas-

ured in channels under the bridge and to the

north of the sand shoal near the bridge (Fig. 2).

The tidal range is approximately 0.8 m. Surface

salinities measured in August 1976 and 1977

ranged from 21 to 24°/0o with the lower values in

the marsh channels at the western extremity

and highest values in the vicinity of the bridge.

Salinities at the mouth of the estuary near the

Little Creek jetties in Chesapeake Bay ranged

from 22 to 24°/00. Current velocities are greatest

at the constriction produced by the bridge. No

current measurements were made, but large ac-

THE NAUTILUS

January 30, 1985

Vol. 99(1)

FIG. 2. Subenvironments and sediment distribution in western branch of Little Creek. Numbers give locations of mollusk

and sediment samples.

Inter tidal Muddy

Sand

B.

Subtidal Muddy

Sand

12

SAND

E *°

E" E2 E E,.

° d

o E L. >

CLAY

GRAIN SIZE

KH ; 3. Summary of sediment grain size analyses. Sand. silt. cla\ proportions of samples. A. Grain size distribution of

sediments in subenvironments, B.

Vol. 99(1)

January 30, 1985

THE NAUTILUS

tive ripples (2-4 cm high) and observable sand

transport on the surface of the shoal (Fig. 2) in-

dicate moderate tidal currents. Muddy and silty

sediments are indicative low current velocities

in most other areas.

Sediment Distribution

Sediment samples were obtained at 29 sta-

tions (Fig. 2) and sediment types were mapped

in the field at numerous locations along a longi-

tudinal traverse from the bridge to station 10.

The pattern of sediment distribution and sedi-

ment character is summarized in Figures 2 and

3. Coarsest sediment is found on the surface of

the sand shoal (Fig. 2). Intertidal and subtidal

muddy sands occur along the edges of the basin,

as small bars, in channels, and in other areas

where tidal currents are strong enough to pre-

vent the accumulation of significant quantities

of silt and clay. Black organic muds occur in

marsh channels, dredged cuts off the main

estuary, and in the central portion of the basin

(Fig. 2). The black muds contain very large

quantities of particulate organic detritus com-

posed primarily ofSpartina alternijlora and ex-

trabasinal macrodetritus such as leaf litter. The

extensive area of embayed marsh at the far

western end of Little Creek baffles currents

during flood tides and traps considerable quan-

tities of mud.

Mollusk Distribution

Mollusks were collected with a 10 cm diameter

pipe dredge or with a shovel in localities where

water depth was less than 1 m. Samples were

washed in the field on a 1 mm sieve. All mollusks

retained were identified and counted. Species

distribution for samples and relative abundance

is given in Fig. 4. Due to lack of uniform sample

volumes precise quantitative comparisons can-

not be made among stations. All species listed

were found living, but at many locations most

specimens collected were dead individuals.

Species characteristic of major subenviron-

ments are listed in Fig. 4. Note that some

species, such as Ilyanassa obsoleta, achieve

greatest abundance on intertidal and shallow

subtidal muddy sand, but are common in other

areas as well. The intertidal muddy sand, sub-

tidal muddy sand, black organic mud sequence

of subenvironments represents a substratum

gradient from basin edge to basin center so it is

not surprising to see strongly intergradational

molluscan assemblages paralleling the gradient.

Da vies (1972) described a suite of molluscan

assemblages from the Rappahannock River

estuary that are very similar to those given in

Fig. 4. Substratum type is only one of several

important controlling factors. Predation also

exerts a strong influence on the distribution of

mollusks. Many estuarine species escape intense

predation by living high in the intertidal zone

(Geukensia, Littorina, Crassostrea), burrowing

deeply into sandy substrata (Mya, Tagelus) or in-

habiting soupy muds that are difficult for preda-

tors to search (Macoma, Mulinia). This flight

from predation seems to be a strong secondary

factor controlling the distribution of some

estuarine mollusks. Shell damage due to preda-

tion by Callinect.es, the blue crab, and possibly

skates or rays was observed on some specimens

if Mercenaria and Mulinia,

Bivalves common in the upper part of the in-

tertidal zone attach to solid substrata by means

of a byssus (Geukensia, Ischadium) or by cemen-

tation (Crassostrea). Littorina occurs in great

abundance in the fringe marsh where it clings to

Spartina. Large bivalves Mercenaria, Mya, and

Tagelus are most abundant on sandy substrata

capable of supporting their body mass. Rapid

burrowers Tagelus and Mya are abundant in

area of shifting substrata such as shallow sub-

tidal bars and intertidal areas. Crepidula and

Anomia are common in subtidal environments

where rocks, shell, or foreign objects provide a

solid substratum for permanent attachment.

The black organic mud is a very soupy substra-

tum that contains a very sparse bivalve fauna.

Three species of Macoma and Mulinia lateralis

have small enough whole animal mass to be sup-

ported by the mud (Stanley, 1970). Macoma is a

deposit feeder that can utilize the abundant

organic detritus of the black mud.

Modified and Unmodified Estuary

A cross-section of a composite unmodified

shallow estuary is shown in Fig. 5A. This com-

posite is based on relatively unmodified portions

of Little Creek and on nearby estuaries that

have undergone little modification. A typical

profile includes a marginal fringing marsh with

either muddy or sandy sediment depending on

THE NAUTILUS

January 30, 1985

Vol. 99(1)

Substratum

Type

species

samples

8 21 13 14 17 12 19 28 15 27 4 16 18 22 26 11 23 25 20 24

A- abundant, C= common, R=rare

FIG. 4. Distribution of molluscan species in subenvironments. Double lines isolate species most

characteristic for substrata at top of diagram.

local current energy. Subtidal margins are

usually muddy sand with a silt and clay content

determined by tidal current and wave activity.

Small islands are produced where intertidal bars

are stabilized by Spartina. The sandy intertidal

zone grades into muddy sand of the shallow sub-

tidal environment which, in turn grades into

black organic mud near the center of the basin.

Black mud or muddy sand is also the typical

bottom sediment in the tidal channels that pene-

trate embayed marsh. In a natural estuary of

the southeastern U.S. virtually the only solid

substratum available is shell or wood fragments.

The following types of physical modification

by man have altered the substratum and mollus-

can distribution in Little Creek:

Type of Change or Structure

1. Shoreline stabilization

and landfill

(bulkheads and rip- rap)

2. Dredging new marsh

channels into embayed

marsh and basin margin

3. Bridge across estuary

4. Refuse Disposal

5. Dredge spoil disposal

Affect on Subenvironment or Substratum

Reduces basin area

Eliminates fringing marsh habitat

Introduces solid substrata (rock and pilings)

Introduces sand, silt and clay (during construction)

Increases area of black organic mud

Increases organic content of muds in open estuary

Alters basin form

Increases velocity of tidal currents that distribute sand and scour

deep channels

Introduces solid substratum

Slightly increases quantity of solid substrata

Increases grain size of sediment

Causes shoaling of bottom

Vol. 99(1)

January 30, 1985

THE NAUTILUS

A) Estuary cross section {natural)

Ltttonno

Crossostreo

Geukensia

Channel deepened by

tidal ecour

B) Estuary cross section (urbanized)

FIG. 5. Schematic estuary cross sections showing changes

in molluscan habitats induced by man. Natural or undis-

turbed estuary, A, urbanized estuary, B.

Fig. 5B illustrates a composite cross-section of

the natural estuary after urbanization. The

basin has been reduced in area and much of the

marsh habitat has been eliminated by "reclama-

tion". This restricts the population size of the

marsh fringe mollusks and affects the trophic

dynamics and nutrient cycling in the system.

Dredging or opening channels in embayed

marsh allows tidal currents to remove coarser

Spartina detritus and mats before it has

thoroughly decayed or been modified by bac-

teria (Odum and LaCruz, 1967). Excess organic

detritus settles into muds of the quiet central

regions of the estuary producing anoxic bottom

conditions. This process occurs naturally, but it

is exacerbated by man's activities in the marsh.

Marsh areas serve as a buffer to the estuarine

system in that they reduce runoff and trap fine

sediment (Welsh and others, 1978). Removing

marsh from the basin, while increasing surface

runoff in adjacent watershed areas, allows large

quantities of silt and clay to be introduced and to

accumulate in regions of low tidal energy. The

mud bottom in the mid-reaches of Little Creek,

around station 20, is covered with a very fluid

flocculent layer of silt and clay up to 0.5 m thick.

Such soupy substratum is usually inhabitated

only by very rare individuals of Macoma

balthica.

Due to the redistribution of sandy dredge spoil

by tidal currents (Fig. 2) certain areas of Little

Creek contain considerably more sand than

would be expected in a natural estuary of com-

parable size. A substantial sand shoal and exten-

sive areas of intertidal and subtidal muddy sand

have enlarged the habitat of molluscan species

prefering a coarser substratum. This might be

viewed as a benefit in that the commercially ex-

ploitable species Mya armaria and Mercenaria

mercenaria are more abundant on sandy bot-

toms; however, unsatisfactory water quality

hampers utilization of the shellfish resource

(Owen and others, 1976).

Almost all solid substrata that are permanent-

ly exposed have been intensively colonized by

mollusks. Crassostrea virginica is most abun-

dant on introduced objects. There are no oyster

"reefs" within Little Creek, but clumps of

oysters established on foreign objects are

dispersed over some intertidal and subtidal

muddy sand flats. Crepidula convexa was found

in great numbers on cans and other foreign

metal substrata. Objects disposed of in the black

mud provide support for molusks such as

Crepidula that would not normally live in that

subenvironment.

Summary

Human activities have significantly altered

the distribution of mollusks in Little Creek by

modifying basin configuration, hydrography,

and substratum distribution. It appears that no

molluscan habitat has been entirely eliminated,

though all have been changed. The large area of

Spartina marsh at the head of the creek is now

protected by the Virginia Wetlands Act (Owen

and others, 1976). Most dredging in the marsh

predates this legislation. As the basin is now en-

circled by urban development future areal con-

striction is unlikely. In terms of the physical en-

vironment, Little Creek estuary and its mollus-

can community seems to be in a mature urban-

ized condition.

This study indicates the ease with which bot-

tom types (substrata) may be characterized and

mapped in a small estuary. The substratum dis-

tribution map successfully delimits the habitats

potentially available to molluscan assemblages

even though an expected assemblage may not

fully occupy areas of preferred substratum at

the instant of sampling. Changes in bottom type

THE NAUTILUS

January 30, 1985

Vol. 99(1)

associated with human acitivities in and around

the estuary can be monitored easily and quickly,

and the ultimate effect on molluscan species or

assemblages can be predicted.

LITERATURE CITED

Bird, S. O. 1970. Shallow • marine and estuarine benthic

molluscan communities from area of Beaufort, North

Carolina. Amer. Assoc. Petrol. Geol. Bull. 54:1651-1676.

Christian, R. R. and R. L. Wetzel. 1978. Interactions be-

tween substrate, microbes, and consumers of Spartina

detritus in estuarines. p. 93-113. In: M. L. Wiley (ed.)

Estuarine Interactions. Academic Press, N.Y. 603 p.

Davis, T. T. 1972. Effects on environmental gradients in the

Rappahannock River estuary and the molluscan fauna.

p. 263-290. In: B. W. Nelson (ed.) Environmental Frame-

work of Coastal Plain Estuaries. Geol. Soc. Amer. Memoir

133. 619 p.

Johnson, R. E. lDTli. Conceptual models of benthic marine

communities, p. 148-159. In: T. J. M. Scopf (ed.) Models

in Paleobiology. Freeman, Cooper, and Co., San Fran-

cisco. 250 p.

Odum, E. P. and A. A. de La Cruz. 1967. Particulate organic

detritus in a Georgia salt marsh - estuarine ecosystem.

p. 383-388. In: G. H. Lauff (ed.) Estuaries. AAAS Publ.

83. Wash., D.C. 757 p.

Owen, D. W., L. M. Rogers and M. H. Peoples. 1976. Shore-

line situation report cities of Chesapeake, Norfolk and

Portsmouth. Va. Inst. Mar. Sci. Spec. Report 136. 87 p.

Stanley, S. M. 1970. Relation of shell form to life habits of

the bivalvia (Mollusca). Geol. Soc. Amer. Meinuir 125.

296 p.

Welsh, B. L., J. P. Herring and L. M. Read. 1978. The ef-

fects of reduced wetlands and storage basins on the stabil-

ity of a small Connecticut estuary, p. 381-401. In: M. L.

Wiley (ed.) Estuarine Interactions. Academic Press, N.Y.

603 p.

MOLLUSCA OF FROG BAYOU, ARKANSAS

Mark E. Gordon

Department of Zoology

University of Arkansas

Fayetteville, Arkansas 72701

ABSTRACT

Very few records ofmollnsks within the Arkansas River basin exist for Arkan-

sas. Twenty-five species were collected from, Frog Bayou, a small tributary of the

Arkansas River in western Arkansas. The fauna is dominated by Interior Basin

species with minimal influence from Interior Highlands endemics. However,

southern, affinities are represented.

The majority of malacological investigations

within the Arkansas River drainage have been

conducted in Oklahoma, Kansas, and Colorado

(e.g. Isely, 1925; Murray and Leonard, 1962;

Wu, 1978), while the lower portions of the basin

remain largely unexamined. Within Arkansas,

only a few incidental references to the occur-

rence of mollusks in this sytem have been pub-

lished (e.g. Kraemer, 1976; Gordon, et al. 1980).

The distribution of mollusks in Frog Bayou, a

small Interior Highlands tributary of the Arkan-

sas River in western Arkansas, is presented.

Materials and Methods

Frog Bayou drains portions of the extreme

southern Ozark Plateaus and the northern slope

of the Arkansas Valley (Ouachita Mountains

province). The permanent flowing channel

crosses the eastern half of Crawford County,

Arkansas (Atoka sandstone). Substrates in

upper Frog Bayou are quite rocky with large

areas of exposed bedrock and rather high gra-

dients. Middle portions are impounded by Lake

Shepherd Springs (304 ha.) and Lake Fort

Smith (212 ha.), while the mouth in inundated by

Vol. 99(1)

January 30, 1985

THE NAUTILUS

Ozark Lake of the McClellan-Kerr Arkansas

River Navigation System. Lower Frog Bayou

may be quite sluggish and include mud and sand

substrate (Arkansas River aluvium). Collections

were made by hand at 15 access areas along the

permanently flowing portion (Figure 1). Addi-

tional records were obtained for Lake Fort

Smith from ichthyoparasite slides prepared by

Cloutman (1974). Voucher specimens are

deposited at the University of Colorado

Museum.

Results

Twenty-five species of mollusks were col-

lected (Table 1). This included seven gastropods,

17 unionacean mussels, and Corbicula fluminea

(Miiller). The fauna above the reservoirs con-

Arkansas

Riv«r

FIG. 1. Location of sampling stations on Frog Bayou,

Crawford County, Arkansas. Open circles represent stations

at which no mollusks were found.

sisted only of pulmonates, primarily Physella

gyrina (Say). Glochidial preparations by Clout-

man (1974) indicate that Quadrula pustulosa

(Lea) and Anodonta grandis Say occur in Lake

Fort Smith. No other mollusks were collected

from either reservoir. Lake Fort Smith is an im-

pediment to water flow which may often be in-

termittent for several kilomenters downstream

during late summer and early autumn. This area

yielded only relicts of Proptera purpurata

(Lamarck) and Lam.psilis hydiana (Lea). The

majority of species were found from Rudy down-

stream to the vicinity of Kibler. No mollusks

were observed near the mouth.

Discussion

The molluscan fauna of Frog Bayou is com-

posed primarily of widespread Interior Basin

species. The only Interior Highlands endemic,

Elimia potosiensis (Lea), oddly was found at the

lowest sampling sight, rather than in rockier,

higher gradient areas upstream representing

more typical habitats for this species. A rather

obscure species, Menetus sampsoni ("Ancey"

Sampson), seems to be associated with the In-

terior Highlands but its distribution has not

been clearly defined and may be more wide-

spread (see Burch and Tottenham, 1980). Fer-

rissia cf. arkansasensis Walker also appears to

be associated with the Interior Highlands. This

form was synonymized under F. rivularis (Say)

by Basch (1963) but seems to be a distinct

species and may be found sympatrically with the

latter. I have only been able to locate F. arkan-

sasensis from a limited area of the Interior

Highlands.

The unionacean component of Frog Bayou is

strictly an Interior Basin fauna. There are no In-

terior Highlands endemics present and most are

very common, widely distributed species. The

presence of Leptodea leptodon (Rafinesque)

establishes this species within the Arkansas

River basin and geographically unites southern

records (e.g. Wheeler, 1918; Isely, 1925) with

northern populations. It also suggests that

Call's (1885: see Scammon, 1906; Murray and

Leonard, 1962) record may have been valid for

Kansas (Neosho River). Additionally, a southern

affinity is represented by three species: Prop-

tera purpurata, Lampsilis hydiana, and L.

satura (Lea). Proptera purpurata and L.

8 THE NAUTILUS

January 30, 1985

Vol. 99(1)

TABLE 1. Mollusca of Frog Bayou, Arkansas. (See Fig. 1 for station localities.

Strophitini Gordon (1981) is elevated to subfamilial status.

hydiana appear to replace P. alata (Say) and L.

radiata siliquoidea (Barnes), respectively, in the

south. Lampsilis satura is closely related to

(and often confused with) L. ventricosa

(Barnes), representing a southern clinal varia-

tion probably fitting within the model presented

by Cvancara (1963). While these three species

are members of the Interior Basin fauna, they

only range north to approximately 38°30' N.

latitude and have colonized Gulf coastal systems

east and west of the Mississippi River. Thus, the

Arkansas River appears to have served as a cor-

ridor through the Interior Highlands for disper-

sal of both common Interior Basin species and a

more restricted southern component.

Acknowledgments

This study was partially funded by a grant

from the University of Arkansas Foundation,

Inc. and was adapted from a thesis submitted in

partial fulfillment of a M.S. degree, University

of Arkansas.

LITERATURE CITED

Basch, P. F. 1963. A review of the recent freshwater limpet

snails of North America. Bull. Mus. Comp. Zool. 129:

399-461.

Burch, J. B. and J. L. Tottenham. 1980. North American

freshwater snails: species list, ranges and illustrations.

Walkerana 1:81-215.

Call, R. E. 1885. Contributions to a knowledge of the fresh-

water Mollusca of Kansas, III: Fresh-water bivalves.

Bull. Washburn Coll. Lab. Nat. Hist. 1:93-97.

Cloutman, D. G. 1974. Parasite community structure of

selected game fishes related to season and water quality

in Lake Fort Smith, Arkansas. Unpublished M.S. thesis,

University of Arkansas-Fayetteville. 124 pp.

Cvancara, A. M. 1963. Clines in three species of Lampsilis

(IVlecypnda: I'nionidae). Malacologia 1:215-226.

Gordon. M. E. 1981. Recent Mollusca of Arkansas with

annotations to systematics and zoogeography. Pror. Ark.

Acad. Sci. 34(1 980): 58-62.

Vol. 99(1)

January 30, 1985

THE NAUTILUS

Gordon, M. E., L. R. Kraemer and A. V. Brown. 1980.

Unionacea of Arkansas: historical review, checklist, and

observations on distributional patterns. Bull. Am.

Malacol. Union 1979:31-37.

Isely, F. B. 1925. The fresh-water mussel fauna of eastern

Oklahoma. Proc. Okla. Acad. Sri. 4:43-118.

Kraemer, L. R. 1976. An evaluation of the effects of dredg-

ing within the Arkansas River Navigation System, vol.

IV: the effects upon the benthic associations. Ark. Water

Resources Res. Center Pub. 46:1-357.

Murray, H. D. and A. B. Leonard. 1962. Handbook of

unionid mussels in Kansas. Univ. Kans. Mus. Nat. Hist.

Misc. Pub. 28:1-184.

Scammon, R. E. 1906. The Unionidae of Kansas, part 1.

Univ. Kans. Sri. Bull. 3:279-373.

Wheeler, H. E. 1918. The Mollusca of Clark County, Arkan-

sas. The Nautilus 31:109-125.

Wu, S.-K. 1978. The Bivalvia of Colorado, part 1: the finger-

nail and pill clams (Family Sphaeriidae). Nat. Hist. Invent.

Colo. 2:1-39.

A NEW SPECIES OF PYGMAEPTERYS VOKES

FROM THE WESTERN PACIFIC (GASTROPODA: MURICIDAE)

Anthony D'Attilio and Barbara W. Myers

Department of Marine Invertebrates

Natural History Museum

P.O. Box 1390

San Diego, California 92112

ABSTRACT

A new species q/Tygmaepterys, P. bellini, from off Okinawa and the Philippine

Islands, is described. Comparison is made with P. funafutiensis (Hedley, 1899),

and P. philclover (Houart, 1984), both western Pacific congeners.

Vokes (1978) erected Pygmaepterys as a sub-

genus of Pterynotus Swainson, 1833, describing

this subgenus as small for a Pterynotus, with six

winged varices, strong spiral cords and numer-

ous axial lamellae; the aperture denticulate on

the outer lip and "occasionally small denticles on

the inner lip." She designated Pygmaepterys

alfredensis (Bartsch, 1915) as the type species.

P. alfredensis is a small six-mm specimen, very

worn, with the early whorls and varices eroded.

The shoulder is concave and the suture deeply

impressed. There are 12 major cords on the

body whorl. P. alfredensis is illustrated in Vokes

(1978) pi. 7, figs, la, lb, 2a and 2b and in Vokes

and D'Attilio (1980) pi. 2, figs, la and lb. The

type locality is Port Alfred, South Africa. Ap-

parently additional specimens have not been

found of this species. Bartsch (1915) in his

original description of P. alfredensis mentions

no denticles on either the inner lip or the outer

lip of the aperture.

Vokes and D'Attilio (1980) described three

new species of Pygmaepterys and assigned one

other species to the genus, but expressed some

doubts regarding the qualitative character of

the inner lip denticles.

As a result of the species studied for this

paper we have concluded that although denticles

in the outer lip are a good character of the

genus, Pygmaepterys, the presence or absence

of nodes or denticles on the inner lip or col-

umella is inconsistent.

The following abbreviations are used:

SDNHM - San Diego Natural History Museum

AMNH - American Museum of Natural

History, New York.

Family Muricidae Rafinesque, 1815

Subfamily Muricopsinae

Radwin and D'Attilio, 1971

Genus Pygmaepterys Vokes, 1978

Type species: Murex alfredensis Bartsch, 1915,

by original designation.

Pygmaepterys bellini new species

Figs. 1-4, 9, 12

Description: Shell small, fusiform; spire elon-

gate with four convex post-nuclear whorls;

10 THE NAl'TIU'S

January 30, 1985

Vol. 99(1)

FIGS. 1 and 2. Pygmtieptcrys hellim D'Attilio and Myers.

Dorsal (1) and apertural (2) views of holotype, SDNHM

83065. Okinawa, Japan. 9.9 mm x 5.5 mm.

FIGS. 3 and 4. Pygmaepterys bellini D'Attilio and Myers.

Dorsal (3) and apertural (4) views of paratype SDNHM

83067a. Philippine Islands. 12.0 mm x 5.5 mm.

FIGS. 5 and 6. Pygmaepterys philcloveri (Houart, 1984).

Dorsal (5) and apertural (6) views. SDNHM 83068. 13.7

mm x 8.00 mm.

FIGS. 7 and 8. PygiititeptrrysfinKifutiettsis (Hedley, 1899).

Dorsal (7) and apertural (8) views of specimen from the

Donald Pisor collection. 12.0 mm x 7.2 mm.

suture impressed. Protoconch of one and one-

half smooth convex whorls, white in color. Aper-

ture narrowly ovate; anal sulcus broadly

U-shaped; inner lip mostly appressed except

very slightly erect anteriorly with one strong

node on columella at entrance to the canal; en-

tire columella stained dark-brown. Outer lip

wavy, reflecting the external spiral cords with

six strong nodelike denticles within. Siphonal

canal open, tapered and recurved. Three distal

portions of previous canals terminate on

siphonal fasciole. Six axial varices per whorl ir-

regularly descend relative to axis of shell. A few

well-defined erect lamellae occur between the

varices and a few regularly-spaced translucent

lamellae crowd against the leading side of the

varix. These lamellae undulate over the spiral

sculpture giving a scabrous appearance to the

shell. Eleven strong regularly-spaced spiral

cords with equally wide interspaces occur on the

body whorl; intermediate minor spiral cords oc-

cur only on the varical flange. The color of shell

varies from translucent white to white with one

to three brown stripes on the body whorl.

Type Material: Holotype SDNHM 83065 from

Okinawa, Ryukyu Islands, Japan (Figs. 1, 2, 9,

12). Paratype SDNHM 83066a and Paratype

83066b from Okinawa. Paratype SDNHM

83067a from the G. Everson collection from

Philippine Islands (Figs. 3, 4). Paratype

SDNHM 83067b from B. Myers collection from

Philippine Islands. Paratype AMNH 213704

from Okinawa.

Type Locality: 52 meters depth off Okinawa,

Ryukyu Islands, Japan.

Dimensions (in mm):

Vol. 99(1)

January 30, 1985

THE NAUTILUS 11

Etymology: Named for Mr. Philip Bellin of

Hawaii who first collected specimens off

Okinawa, Japan.

Discussion: Of the six specimens studied,

three have immature lips with no nodes or denti-

cles. Paratype 83066a has six denticles on the

outer lip and three nodes on the anterior wall of

the columella. Paratype 83066b has seven denti-

cles on the outer lip and one node on the col-

umella at the entrance to the siphonal canal.

Comparison is made with P. funafutiensis

(Hedley, 1899). See Table 1. The type specimen

of P. funafutiensis is from Funafuti Atoll, Ellice

Islands and is 9 mm in height. Specimens in the

San Diego Natural History Museum, lot #71304,

dredged from 183 m in Pokai Bay, Oahu,

Hawaii, consist of four specimens, the larger of

which is 9.8 mm x 6.2 mm and two fragments.

Both the type specimen from Ellice Islands and

the larger specimen from Hawaii are illustrated

in Vokes and D'Attilio (1980), pi. 2, figs. 4, 5a

and 5b. P. funafutiensis has a heavier coarser

shell with six axial varices and five postnuclear

whorls. There are five strong spiral cords on the

body whorl with wide interspaces, each inter-

space with five to seven incised lines. P. bellini

has 11 regular, moderately strong cords with

equal interspaces and intermediate cords only

on the varical flange. Growth lamellae in P.

funafutiensis are close-set and three to four

times as numerous as in P. bellini. P. funafu-

tiensis has five apertural denticles on the outer

lip; the first and second denticles posteriorly are

most prominent. P. bellini has six denticles of

even strength. The columella of P. funafutiensis

lacks any trace of the brown stain prominent in

P. bellini. The color of P. funafutiensis is tan

with a diffused brown band subsuturally and one

at the base of the body whorl. A specimen of P.

funafutiensis from the Philippine Islands in the

collection of Donald Pisor of San Diego, Califor-

nia, measures 12 mm x 7.2 mm (Figs. 7, 8, 11,

14). This specimen does not differ in any essen-

tial respect from those from Hawaii except that

TABLE 1. Comparison of Pygmaepterys bellini new species, P. philcloveri Houart and P. funafutiensis (Hedley).

12 THE NAUTILUS

January 30, 1985

Vol. 99 (1)

FIG. 9. Detail drawing of protoconch of P. bellini. Holotype

SDNHM 83065.

FIG. 10. Detail drawing of protoconch of P. philcloveri.

SDNHM 83068.

FIG. 11. Detail drawing of protoconch of P. fmwfutiensis.

Donald Pisor collection.

FIG. 12. Detail drawing of aperture of P. bellini. Holotype

SDNHM 83065.

FIG. 13. Detail drawing of aperture of P. philcloveri.

SDNHM 83068.

FIG. 14. Detail drawing of aperture of P. junafutiensis.

Donald Pisor collection.

FIG. 15. Detail drawing of operculum of P. philcloveri.

SDNHM 83068.

nodes on the columella number two instead of

three.

A second new species of Pygmaepterys had

been under study by us. A description of this

species has recently been published by Houart

(July, 1984). The description prepared by us

follows:

Pygmaepterys philcloveri (Houart, 1984)

1984 Poirieria (Pazinotus) philcloveri Houart,

Informations, series 12, nos. 2, 3, pp. 127-130.

(off Samal Id., Davao, Mindanao Id. Philippines).

Figs. 5, 6, 10, 13, 15

Description: Shell strongly fusiform, spire

moderately elongate, suture moderately im-

pressed. Protoconch of one and three-fourths

conical, convex smooth, pale brown whorls; five

post nuclear whorls. Anal sulcus u-shaped and

deep. Inner lip appressed posteriorly, strongly

erect two- thirds distance from siphonal canal;

five elongate denticles occur on lower portion of

columella, the most anterior denticle situated

directly above the entrance to siphonal canal.

Outer lip erect, wavy, reflecting the external

spiral sculpture with six denticles arranged as

follows: two small denticles posteriorly followed

by a very large denticle midway, two slightly

smaller denticles below and a large bifid denticle

above entrance to siphonal canal. Siphonal canal

open, broad and tapering distally becoming

recurved and tubelike. Three distal portions of

previous canals terminate on siphonal fasciole.

Seven axial varices on spire diagonally descend

to the body whorl where the varices number

only six. Varices blade-like continue above the

shoulder and abut the suture. Entire surface of

shell with very fine scabrous close-set axial

growth lamellae. Spiral sculpture of 12 cords

starting at shoulder; first five prominent and

somewhat spinose at the varical margins with

prominent open spines at the shoulder; inter-

spaces wide; remaining seven cords narrower

and more close-set with diminishing inter-

spaces. Operculum typically Muricopsinae.

Color: Rust-brown with a pale band starting at

the shoulder and encompassing the first three

cords. The rust-brown is much darker below the

suture. The distal portion of the canal is gray-

white and the aperture is white. Length of shell

13 mm.

Discussion: P. philcloveri in comparison with

P. bellini has a slightly larger, more robust

Vol. 99(1)

January 30, 1985

THE NAUTILUS 13

shell. See Table 1. The shell is distinguished

most significantly in the apertural characters.

The aperture of P. philcloveri is irregularly

ovate and the inner lip strongly erect over most

of its length. There is a deep anal sulcus in com-

parison to the broad shallow sulcus of P. bellini.

Although the number of denticles is the same,

the arrangement and size differ in that P. bellini

has six denticles of equal strength, while P.

philcloveri has two small denticles posteriorly

followed by a very large denticle midway on the

outer lip with two smaller denticles following

and one large bifid denticle above the entrance

to the siphonal canal. P. bellini has six varices ir-

regularly descending to the body whorl, while P.

philcloveri has seven regularly descending axial

varices on the spire reduced to six on the body

whorl, the varix lacking is between the final

varix and the preceding one. The entire surface

of P. philcloveri consists of fine, strong, close-

set scabrous lamellae in contrast to the few

translucent erect lamellae of P. bellini. The

overall brown stain on the columella of P. bellini

is not found in P. philcloveri. P. bellini has a

white shell with three brown bands and P. phil-

cloveri has a rust brown shell with a pale brown

band.

P. funafutiensis (Hedley, 1899) differs from P.

philcloveri in the protoconch which is depressed

and not conical. The inner lip of P. funafutiensis

is mostly appressed, not erect as in P. phil-

cloveri and there are five denticles on the outer

lip of more or less equal strength in contrast to

the six denticles of unequal size and strength of

P. philcloveri. The spiral sculpture of P. funafu-

tiensis consists of five very strong major cords

with five minor cords while P. philcloveri has 12

strong major cords. The growth lamellae of P.

funafutiensis are very numerous and appressed

over the entire shell, whereas in P. philcloveri

the lamellae are erect and only appressed over

the spiral cords. The leading side of the aper-

tural varix of P. funafutiensis has five strong

concave troughs, a reflection of the strong ex-

terior cords. The apertural varix of P. phil-

cloveri is regularly wavy reflecting the spiral

cords.

Acknowledgments

We wish to thank the following: Mr. Philip

Bellin of Hawaii for donating specimens of

Pygmaepterys bellini new species to the Natural

History Museum of San Diego; Mr. Gene Ever-

son of Lauderhill, Florida, for donating his

specimen of P. bellini from the Philippine

Islands; Mr. Victor Dan of Manila, Philippine

Islands, for allowing us to study his specimens

of P. philcloveri and for donating a specimen to

our museum; Mr. Robert Yin of La Jolla, Cali-

fornia, for bringing the specimens of P. phil-

cloveri to our attention; Mr. Donald Pisor of

San Diego, California, for allowing us to study

his very fine example of P. funafutiensis

(Hedley,' 1899). We are grateful to Mr. David K.

Mulliner for the photography used in this paper.

Dr. William K. Emerson and Mr. Walter E.

Sage, III of the American Museum of Natural

History read a draft of the manuscript.

LITERATURE CITED

Bartsch, P. 1915. Report on the Turton collection of South

African Marine Mollusks with additional notes on other

South African Shells contained in the United States

Museum. Bull. 91 USNM. 1-305 pp. 54 pis.

Hedley, C. 1899. The Mollusca of Funafuti. Mem. Aust.

Mus. 3(7):397-488, 49 figs. Pt. 1. Gastropoda.

Houart, R. 1984. Poirieria (Pazinotus) philcloveri, a new

species from the Philippine Islands (Gastropoda: Murici-

dae: Muricinae). Informations 12(2-3): 127-130. 1 pi.

Radwin, G. and A. D'Attilio. 1971. Muricacean supraspecific

taxonomy based on the shell and radula. Echo 4:55-67.

Rafinesque, C. S. 1815. Analyse de la nature, ou tableau du

univers et des corps organises. Barravecchia, Palermo.

Vokes, E. 1978. Muricidae (Mollusca: Gastropoda) from the

eastern coast of Africa. Ann. Natal Mus. 23(2):375-418,

8 pis.

Vokes, E. and A. D'Attilio. 1980. Pygmaepterys, a newly

described taxon of Muricidae (Mollusca: Gastropoda) with

description of three new species from the Cenozoic of the

western Atlantic. Tulane Studies in Geo. and Paleo.

16(2):45-54, 2 pis.

14 THE NAUTILUS

January 30, 1985

Vol. 99(1)

MUREX HAMATUS HINDS, 1844, A LIVING WEST

AMERICAN SPECIES ASSIGNED TO THE NEOGENE PACIPHILE

GENUS, PTERORYTIS CONRAD (GASTROPODA: MURICIDAE).

William K. Emerson

Department of Invertebrates

American Museum of Natural History

New York, New York 10024

ABSTRACT

Pterorytis hamatus (Hinds), an inhabitant of Ecuadorian and Peruvian

waters, is the only known extant species of this muricacean genus. Pterorytis was

widely distributed in the tropical western Atlantic during the Neogene. By the end

of the Pliocene, however, the constituents of this Paciphile genus apparently

became extinct in the western Atlantic, with P. hamatus surviving on the Pacific

side of the Panamanian land bridge. The typological specimens o/Murex hamatus

were examined, and a live-collected specimen was studied. On the basis of oper-

cular, radular and shell characters, the assignment of this species to the muricid

subfamily Ocenebrinae is confirmed.

Some twenty-five years have passed since my

review of the muricid genus Pterorytis appeared

(Emerson, 1959). At that time the genus was

believed to consist of extinct east American

Neogene species. More than a decade ago, how-

ever, Vokes (1971, pp. 56, 141, and Vokes in

Keen, 1971, p. 536) recognized that a long-

misunderstood species from Ecuador, described

by Hinds in 1844 as Murex hamatus, was a living

representative of this Paciphile genus. Previous-

ly, Hinds' species was referred to other muricid

genera, including Tritonalia, Ocenebra and

Ceratostoma and was erroneously placed in the

synonymy of Ceratostoma lugubre (Broderip,

1833), a species that also was originally de-

scribed from Ecuador.

Through the kindness of Carol Skoglund of

Phoenix, Arizona, a specimen of Pteror^ytis

hamatus, taken alive by shrimpers working out

of San Pablo, Ecuador, was submitted to me for

study. As the preservation of the soft parts of

this specimen presented an opportunity to

establish the taxonomic placement within the

Muricidae of this rarely found species, the pre-

sent study was undertaken.

Family Muricidae Rafinesque, 1815

Subfamily Ocenebrinae Cossmann, 1903

Genus Pterorytis Conrad, 1862

Pterorytis hamatus (Hinds, 1844)

Figs. 1-5, 7-9

Murex hamatus Hinds, 1844a, p. 128; Hinds, 1844b, p. 8,

pi. 3, figs. 11, 12; Reeve, 1845, Murex, sp. 119, pi. 27, fig.

119 ("Museum Belcher"); Sowerby, 1879, Murex. sp. 203, p.

44, pi. 16, fig. 159 ("Voy. Sulph., p. 8").

Murex lugubris Broderip, Tryon, 1880, p. 124, pi. 37, fig.

439 only; Keen 1958, p. 357, in part. Not M. lugubris

Broderip, 1833.

Tritonalia hamata (Hinds), Dall, 1909, p. 220, "Guayaquil,

Ecuador, and south to Paita, Peru"); Smith, 1939, p. 15,

(cites Dall's distributional data).

Ceratostoma hamata (Hinds), Keen, 1966, p. 269, pi. 46

fig. 11 ("figured syntype, from Belcher coll. to S. Hanley to

H. Harvey; also figured by Reeve, [1845]").

Pterorytis hamatus (Hinds), Vokes, 1971, pp. 56, 141;

Keen, 1971, p. 536, fig. 1039 ("BM Syntype", p. 951); Fair,

1976. p. 47, pi. 23, fig. 360 ("BM(NH) Holotype (EH

V[okes])", p. 131).

Ocenebra? hamata (Hinds), Radwin and D'Attilio, 1976,

pp. 121. 122, pi. 14. fig. 2 ("off Peru, Inst. Del Mar, Peru,"

p. 259).

Type locality: "Bay of Guayaquil, [Ecuador],

from a muddy floor, in twenty-one fathoms"

[38 m].

Known range: Golfo de Guayaquil (type speci-

mens) and off San Pablo, Guayas Province

(AMNH 213692), Ecuador, and Paita, Peru

(Dall, 1909, p. 220; cited specimens were not

Vol. 99(1)

January 30, 1985

THE NAUTILUS 15

FIGS. 1-3. Pterorytis hamatus (Hinds, 1844), off San Pablo, Guayas Province, Ecuador (AMNH 213692); height = 38.6 mm.

FIGS. 4 and 5. Original figures of Murex hamatus (Hinds,

1844b, figs. 11, 12); height = 29.2 mm.

found in the NMNH collection, teste J.

Rosewater, August 10, 1984).

Diagnosis: Shell rhomboid in outline, 23 mm

to 40 mm in height. Spire elongated, of 3V2

nuclear whorls; 4 post nuclear whorls. Six

raised, spiniform varices per whorl ornamented

with slightly recurved laciniations and one or

two major ribs on faces of varices. Aperture

oval, with an acute labial tooth anteriorly,

marked here and on the previous varices of body

whorl by a V-shaped notch behind varical tooth.

Canal short, closed, grooved behind. Color pale-

yellow to tan (modified after Fair, 1976, p. 47).

Radular characters: Typical of Ocenebrinae;

compare our Figure 7 with our Figure 6 of the

radular dentition of Ocenebra erinaceus (Linne,

1758), the type species of Ocenebra Gray, 1847.

Opercular characters: Ocenebrine, see Figs.

8, 9.

Remarks: The larger of the two "syntypes" of

Murex hamatus in the British Museum (Natural

History) (1907.12.30.134, here illustrated,

Figures 4, 5), measures 29.2 mm (sans nucleus).

This specimen (29.2 mm in length) appears to be

the one figured by Hinds (1844b, pi. 3, Figs. 11,

FIGS. 6 and 7. 6, Radular dentition of Ocenebra erinaceus (Linne, 1758), after Radwin and

D'Attilio, 1976, fig. 73. 7, Radular dentition of Pterorytis hamatus (Hinds, 1844), (AMNH

213692), drawing by Anthony D'Attilio. left side, central tooth; right side, 1 lateral tooth.

16 THE NAUTILUS

January 30, 1985

Vol. 99(1)

FIGS. 8 and 9. Operculum of Pterorytis ham.atus

(Hinds, 1844), (AMNH 213692), left side, internal

view; right side, external view; drawings by

Anthony D'Attilio; greatly enlarged.

12) and Reeve (1845, Murex, pi. 27, Fig. 119),

despite the fact that Hinds (1844a, p. 128) cites

13V2 English lines for the axis of the shell [ = 28.5

mm]. 13.5 French lines would be 30.3 mm. Keen

(1966, p. 269) translated it to 34 mm. Keen (op.

cit.) also recorded a second specimen, a

topotype, in the general collection of the British

Museum (1842.1.22.418), which Hinds in 1842

had labeled "Murex, sp.". It is a juvenile,

measuring 23.2 mm in height, with an immature

outer lip. The present specimen from off San

Pablo, Ecuador (AMNH 213692, here illus-

trated, Figures 1-3, 7-9), is a larger (38.6 mm),

more robust example of this species. The

specimen identified as ?Ocenebra hamata by

Radwin and DAttilio (1976, pi. 14, Fig. 2, from

"off Peru") may represent another species. The

shell is larger (66.8 mm in height), with the

labial tooth situated medially, and it is colored a

darker tan, tinged with brown.

No other specimens of this species were

located in any of the leading U.S. museum col-

lection nor in such private collections as that of

Helen DuShane and Donald R. Shasky. The

failure to find additional specimens in these col-

lections attests to the apparent rarity of this

species.

Systematics and Zoogeography

I'trrorytis hintmtus appears to be most closely

related to the type species of Pterorytis, P. um-

brifer (Conrad," 1832, p. 17, pi. 3, Fig. 1; Olsson

and Harbison, L953, pi. 35, Fig. 2; Emerson,

1959, Fig. 1), a species not uncommonly found in

Pliocene deposits (Yorktown formation) of

Virginia. Both species have a shell well-marked

by a V-shaped indentation behind the acute

labial tooth, as well as six foliated and spiniform

varices. Pterortyis hamatus is, therefore,

referable to Pterorytis (sensu stricto) and is the

only known survivor of this Paciphile genus,

which during the Neogene flourished in the

tropical western Atlantic. The other extinct

species of Pteroi'ytis (see Olsson and Harbison,

1953, p. 252; Emerson, 1959, p. 4; Olsson and

Petit, 1964, p. 549; Vokes, 1971, p. 141) have

been referred to the subgenus Neurarhytis

Olsson and Harbison (1953, p. 252) of which P.

jluviana (Da\\, 1903, p. 1633, pi. 60, Figs. 20, 21;

Emerson, 1959, Fig. 2) is the type species.

These taxa have heavier shells of moderate size,

with four wide, terminally recurved, finely

foliated varices per whorl and a weakly devel-

oped labial tooth without a prominent labial

suture.

Pterorytis (Mierorhytis) pecki (Emerson,

1959, p. 6, Fig. 4) from the Miocene of Veracruz,

Mexico, may be referable to the genus Cerato-

stoma Herrmannsen, 1846, type species C. nut-

talli (Conrad, 1837, p. 264, pi. 20, Fig. 22), as

Vokes (1971, p. 125) has indicated. However, P.

peeki, the type species of Mierorhytis Emerson

(1959), does possess a marginal indentation

below the labial tooth, which is characteristic of

Pterorytis, and has a shorter spire than typical

species of Ceratostoma.

At the present time the geographical range of

Ceratostoma is from Japan to northern Mexico

(Cape San Lucas, Baja California Sur). Vokes

(1964, p. 23; 1974, p. 8), however, reports in the

Miocene of Silverdale, North Carolina (Trent

marl of Richards, 1943) the presence of several

amphi-North Pacific muricid genera, including

Ceratostoma, that are no longer living in the

western Atlantic. During the Neogene, the

genus Ceratostoma is known to have been pre-

sent in western Atlantic waters (North Carolina

and possibly from Vera Cruz, Mexico), as well as

in northeastern Pacific waters (Mio-Pliocene of

California, Hall, 1959).

Acknowledgments

I am deeply indebted to Carol Skoglund for

her kindness in calling to my attention and

Vol. 99(1)

January 30, 1985

THE NAUTILUS 17

donating her specimen to the AMNH. I thank

John Taylor (BM(NH)) for the loan of Hinds'

typological specimens and Anthony D'Attilio

and Barbara Myers (SDNHM) for providing the

line drawings of the radular dentition and the

operculum and for preparing the radular mount,

respectively. The following friends and col-

leagues assisted by searching their collections

for specimens: Robert Robertson and Mary A.

Garback (ANSP), Terrence M. Gosliner (CAS),

James H. McLean (LACMNH), Ruth D. Turner

and David H. Backus (MCZ at Harvard), Joseph

Rosewater (NMNH), Anthony D'Attilio

(SDMNH), Helen DuShane of Whittier, CA, and

Donald R. Shasky of Redlands, CA. George and

Wylda Stephens of Virginia Beach, VA, and

Richard E. Petit of North Myrtle Beach, SC,

generously provided fossil specimens of

Pterorytis.

I also acknowledge the contributions of my

AMNH colleagues: Walter E. Sage, III for

technical services, and Peter Harries and Jeff

Teitelbaum for the photography.

LITERATURE CITED

Broderip, W. J. 1833. Characters of new species of Mollusca

and Conchifera, collected by Mr. Cuming. Proc Zool. Soc.

London, for 1832, pp. 173-179 (Jan. 14, 1833).

Conrad, T. A. 1832. Fossil shells of the Tertiary formations

of North America. Philadelphia, vol. 1, pp. 1-28, pis. 1-14.

1837. Descriptions of new marine shells from

upper California, collected by Thomas Nuttall, Esq. Jour.

Acad. Nat. Sci. Philadelphia, vol. 7, pp. 227-268, pis.

17-20.

1862. Catalogue of the Miocene shells of the

Atlantic slope. Proc. Acad. Nat. Sci. Philadelphia, vol. 14,

pp. 559-582.

Dall, W. H. 1903. Contributions to the Tertiary fauna of

Florida. Trans. Wagner Free Inst. Philadelphia, vol. 3, pt.

4, pp. l-xiv + 1219-1654, pis. 48-60.

1909. Report on a collection of shells from Peru,

with a summary of the littoral marine Mollusca of the

Peruvian zoological province. Proc. U.S. Nat. Mus.. vol.

37, no. 1704, pp. 147-294, pis. 20-28.

Emerson, W. K. 1959. The gastropod genus Pterorytis.

Amer. Mus. Novitates, no. 1974, 8 pp., 4 figs.

Fair, R. H. 1976. The Murex book: an illustrated catalogue of

Recent Muricidae (Muricinae, Muricopsinae, Ocenebrinae).

Honolulu, 138 pp., 56 text figs., 21 pis.

Hall. C. A. Jr. 1959. The gastropod genus I'iratostoma.

Jour. Paleont., vol. 33, no. 3, pp. 428-434, 4 text figs. pis.

61-63.

Herrmannsen, A. N. 1846. Indicis generum malacozoorum

primordia, Kassel, vol. 1. pp. 1-232, [pp. 233-637, 1847].

Hinds, R. B. 1844a. Descriptions of new species of Scalaria

■and Murex. from the collection of Sir Edward Belcher, CB.

Proc. Zool. Soc. London, for 1843, pp. 124-129 (March,

1844).

1844b. The zoology of the voyage of H.M.S.

Sulphur under the command of Capt. Sir Edward Belcher

. . . during 1836-1842, London, Mollusca, pt. 1, pp. 1-24,

pis. 1-7 (July, 1844).

Keen, A. M. 1958 Sea shells of tropical west America.

Stanford, California, xi + 624 pp., illus.

1966. West American mollusk types in the Brit-

ish Museum (Natural History) II. Species described by R.

B. Hinds. The Veliyer. vol. 8, no. 4, pp. 265-275, 6 text

figs., pis. 46-47.

1971. Sea Shells of tropical west America, 2nd

ed., Stanford, California, xiv + 1,064 pp., illus.

Olsson, A. A., and Anne Harbison. 1953. Pliocene Mollusca

of southern Florida. Monogr. Acad. Nat. Sci. Philadel-

phia, no. 8, pt. 1, pp. 27-361, pis. 1-65.

Olsson, A. A., and R. E. Petit. 1964. Some Neogene Mollusca

from Florida and the Carolinas. Bull. Amer. Paleont., vol.

47, no. 217, pt. 2, pp. 527-574, pis. 77-83.

Radwin, G. E., and A. D'Attilio. 1976. Murex Shells of the

World, an illustrated guide to the Muricidae, Stanford,

California, 284 pp., 98 text figs., 32 pis.

Reeve, L. A. 1845. Conchologia Iconica, or illustrations of

the shells of molluscous animals, London, Monograph of

the genus Murex, text + Murex pis. 1-34 [pi. 27, Aug.

1845],

Richards, H. G. 1943. Additions to the fauna of the Trent

marl of North Carolina. Jour. Paleont., vol. 17, no. 5, pp.

518-526, pis. 85, 86.

Smith, Maxwell. 1939. An illustrated catalogue of 'the Recent

species of the rock shells. Muricidae, Thaisidae, and Coral-

liophilidae, Lantana, Florida, 83 pp., text figs, a-z, 21 pis.

Sowerby, G. B. II. 1879. Thesaurus Conch yliorum, or mono-

graphs of the genera of shells. London, vol. 4, Monograph

of the genus Murex Linnaeus, pts. 33-35, 55 pp., pis.

380-403 [Murex, pis. 1-24].

Tryon, G. W., Jr. 1880. Manual ofConchology, ser. 1, vol. 2,

Muricidae, Purpuridae, Philadelphia, 289 pp., 70 pis.

Vokes, E. H. 1964. Supraspecific groups in the subfamilies

Muricinae and Tritonaliinae (Gastropoda: Muricidae).

Malaeologia, vol. 2, no. 1, pp. 1-41, pis. 1-3.

1971. Catalogue of the genus Murex Linne

(Mollusca: Gastropoda; Muricinae, Ocenebrinae). Bull.

Amer. Paleont., vol. 61, no. 268, 141 pp.

1974. A new species and subgenus of Australian

Demomurex (Gastropoda: Muricidae). Jour. Malac. Soc.

Australia, vol. 3, no. 1, pp. 1-14, pis. 1-3.

18 THE NAUTILUS

January 30, 1985

Vol. 99(1)

CORBICULA FLUMINEA (BIVALVIA: CORBICULIDAE) IN THE

STATE OF WASHINGTON IN 1937, AND IN UTAH IN 1978

Clement L. Counts, III

College of Marine Studies

University of Delaware

Lewes, Delaware 19958

Washington

The exotic Asiatic bivalve, Corbicula Jluminea

(Muller, 1774) was first detected in North

America at Nanaimo, Vancouver Island, British

Columbia, in 1924 (Counts, 1981). The first

report of C. jluminea in United States waters is

that of Burch (1944) for specimens collected

along the Columbia River at Knappton, Pacific

County, Washington, in 1938. These are the

earliest published records for C. Jluminea in

North America (McMahon, 1982, 1983; Counts,

1983).

A survey of the Corbiculidae collections held

in the Department of Malacology of the Los

Angeles County Museum of Natural History

(LACM), conducted in June 1984, revealed a lot

of Corbicula Jluminea collected in April 1937 at

Raymond, Pacific County, Washington (LACM

64359). The label accompanying the specimens

states "Introduced from Japan. Immaculate

Heart Collection. A. Burch". It does not specify

a body of water as a collection locality. No

details are available on either the Immaculate

Heart Collection or the collector. The shape and

color of the specimens is consistant with the

"white form" described by Hillis and Patton

(1982). A review of zoogeographic records for C.

ihinmiiii in Washington found thai specimens

were collected from the Willapa River at Ray-

mond in 1971 (Counts, 1983) indicating that C.

Jluminea has survived in this region of Washing-

ton and suggesting that LACM 64359 may be

representative of the population of origin.

Although LACM 64359 does not significantly

alter the date of the introduction of Corbicula

Jluminea into United States waters, it is signifi-

cant since it reinforces the hypothesis of a west

coast introduction during the 1920's-1930's

(Britton and Morton, 1979).

Acktmtrlnhin/cnts: I would like to thank Mr. C.

Clifton Coney and Dr. James H. McLean, Los

Angeles County Museum of Natural History, for

their assistance.

Utah

The Asiatic bivalve, Corbicula Jluminea

(Muller, 1774) has been reported from Utah only

in general geographic terms (Cherry, et aL,

1980a, b; McMahon, 1982, 1983). These reports

are in the nature of either lists of states where

C. Jluminea does or does not occur or United

States maps with the State of Utah colored to

indicate the presence of the species. No precise

locality descriptions have been published for C.

Jluminea in Utah. A survey of 26 malacological

collections held in museums throughout the

United States, conducted between 1979 and

1982 failed to reveal any specimens collected in

Utah (Counts, 1983).

A survey of the malacological collections of

The Ohio State University Museum of Zoology

(OSUM) conducted in June 1984 revealed two

lots of Corbicula Jluminea collected in Utah.

Both lots (OSUM 52430 and OSUM 52431) were

collected in the Sevier Reservoir (also known as

Yuba Reservoir), 15.2 km northeast of Scipio,

Juab County, Utah on 4 July 1978 by Richard L.

Denton (Fig. 1). The shape and color of the

specimens is consistant with the "white form" of

Hillis and Patton (1982).

The Sevier River flows approximately 520 km

from the Paunsaugunt Plateau of southwestern

Utah north to Juab County where it then flows

southwest to Sevier Lake. The river is located in

the Great Basin and thus has no outlet to the

oceans. Further, there is no connection with any

other river in which Corbicula Jluminea is

known to exist. This indicates that C Jluminea

was introduced into the Sevier River by means

other than normal movements of the bivalves in

the substratum. Zoogeographic studies of C.

ih < in i in a reveal the nearest known population is

Vol. 99(1)

January 30, 1985

THE NAUTILUS 19

H

FIG. 1. Location of Corbicula fluminea in the Sevier River,

Utah (Scale bar = 100 km).

located in Lake Meade of Arizona-California-

Nevada (Counts, 1983). Whether the agent of in-

troduction into the Sevier River was man or

waterfowl is speculative at present.

Acknowledgments: I would like to thank Dr.

David H. Stansbery, The Ohio State University

Museum of Zoology, for allowing me to examine

their collections. Both of these researches were

supported by the U. S. Nuclear Regulatory

Commission (Contract No. NRC-03-84-063).

LITERATURE CITED

Britton, J. C. and B. Morton. 1979. Corbicula in North

America: the evidence reviewed and evaluated. IN: Pro-

ceedings of the First International Corbicula Symposium,

J. C. Britton, Ed. Texas Christian University Research

Foundation (Fort Worth), pp. 250-287.

Burch, J. Q. 1944. Checklist of west American mollusks.

Minutes, Concol. Club Southern California 38:18.

Cherry, D. S.. J. Cairns, Jr. and R. L. Graney. 1980a. Asiatic

clam invasion: causes and effects. Water Spectrum

12:18-24.

Cherry, D. S., J. H. Rodgers, Jr., R. L. Graney and J. H.

Cairns, Jr. 1980b. Dynamics and control of the Asiatic

clam in New River. Virginia. Bulletin, Virginia Water

Resources Center, 123:1-72.

Counts, C. L., III. 1981. Corbicula fluminea (Bivalvia:

Sphaeriacea) in British Columbia. The Nautilus 95(1):

12-13.

1983. Bivalves in the genus Corbicula Miihlfeld,

1811 (Mollusca: Corbiculidae) in the United States: sys-

tematics and zoogeography. Ph. D. Dissertation. Univer-

sity of Delaware, xxii + 451 pp.

Hillis, D. M. and J. C. Patton. 1982. Morphological and elec-

trophoretic evidence for two species of Corbicula

(Bivalvia: Corbiculidae) in North America. American

Midland Naturalist 108(l):74-80.

McMahon, R. F. 1982. The occurrence and spread of the in-

troduced Asiatic freshwater bivalve, Corbicula. fluminea

(Muller) in North America: 1924-1981. The Nautilus

96(4):134-141.

1983. Ecology of an invasive pest bivalve, Cor-

bicula. IN: The Mollusca, Vol. 6, Ecology, W. D. Russell-

Hunter. Ed. Academic Press (New York), pp. 505-561.

TROPICAL VERONICELLID, LAEVICAULIS ALTE (FERUSSAC),

ESTABLISHED IN SOUTHERN TEXAS

Raymond W. Neck

Texas Parks and Wildlife Department

4200 Smith School Road

Austin, Texas 78744

A number of tropical gastropods have been in-

troduced into urban locations in Brownsville,

Cameron County, Texas (Neck, 1976). Included

are several veronicellid slugs, two of which were

reported in an earlier communication (Neck,

1976). An additional species has been observed

and was tentatively identified as Pseudoveroni-

cella liberiana (Gould) (Neck, 1981). Recently,

specimens from this population were sent to

Lothar Forcart of Basel, Switzerland, and Jose

Willibaldo Thome of Porto Alegre, Brazil, both

of whom identified this species as Laevicaulis

alte (Ferussac, 1821).

Laevicaulis alte was most likely native to cen-

20 THE NAUTILUS

January 30, 1985

Vol. 99(1)

tral or eastern Africa (Forcart, 1953; in litt.).

The type locality of this taxon is Pondicherry,

India (Forcart, 1969). Human-mediated disper-

sal has allowed this species to establish popula-

tions in Madagascar, India, Indonesia, the

Philippines, Australia and various island groups

in Oceania (Forcart, 1953; Solem 1959, 1964).

This southern Texas record apparently repre-

sents the first establishment of L. alte in North

America. Neither Hanna (1966) nor Dundee

(1974) list L. alte, although this species has been

established in Hawaii since the 1920's (as

Veronicella leydigi (Simroth), in Cockerell,

1925). Summary papers by Baker (1925) and

Thome (1975a, b) do not list L. alte for the

Americas.

First observed in Brownsville in 1975, L. alte

has subsequently become the most abundant

veronicellid in urban residential yards. Later

reports will discuss life history and interactions

with other introduced veronicellids.

I thank Lothar Forcart and Jose Willibaldo

Thome for their prompt identification of the

slug.

LITERATURE CITED

Baker, H. B. 1925. North American Veronieellidae. Proc.

Acad. Nat. Sci. Philadelphia 77:157-184.

Cockerell, T. D. A. 1925. A visit to the Hawaiian Islands.

The Nautilus 38:76-85.

Dundee, D. S. 1974. Catalog of introduced molluscs of

eastern North America (North of Mexico). Sterkiana

55:1-37.

Forcart, L. 1953. The Veronieellidae of Africa (Mollusca,

Pulmonata). Ann. Musee Royal Congo Beige. Tervueren,

Zool. 23:1-110.

1969. Veronicellid land slugs from the New

Hebrides, with description of Semperula solemi. new

species. Fieldiana: Zoology 51(12):147-156.

Hanna, G. D. 1966. Introduced mollusks of western North

America. Occ. Papers California Acad. Sci. 48:1-108.

Neck, R. W. 1976. Adventive land snails in the Brownsville,

Texas area. Southwestern Naturalist 21:133-135.

1981. Noteworthy gastropod records from

Texas. Texas Conchologist 17:69-72.

Solem, A. 1959. Systematics and zoogeography of the land

and fresh- water Mollusca of the New Hebrides. Fieldiana:

Zoology 43:1-238.

1964. New records of New Caledonian non-

marine mollusks and an analysis of the introduced mol-

lusks. Pacific Science 18:130-137.

Thome, J. W. 1975a. Estado atual da sistematica dos

veronicelideos americanos (Mollusca, Gastropoda). Arq.

Mus. Nac.. Rio de Janeiro 55:155-165.

1975b. Os generos da familia Veronieellidae

nas Americas (Mollusca; Gastropoda). Iheringia Zool.

48:3-56.

NEW RECORDS OF MARINE MOLLUSCA FROM

KHOR ABDULLAH, IRAQ

L. A. J. Al-Hassan and Z. I. Al-Hasani

Marine Science Centre

University of Basrah

Basrah, Iraq

During the period of November 1982 to

November 1983 a number of mollusks were ob-

tained from the surface of sediments in Khor

Abdullah in the northwest section of the

Arabian Gulf.

The Khor Abdullah area is situated in a shal-

low sea and much of the coastline is bordered by

mud and sandy silt (S. A. Darmoian, personal

communication). The depth ranges between 5

and 12 meters. The new records include nine

gastropods and sixteen bivalves:

1. Euchelis asper (Gmelin, 1791)

2. Turritella terebra (Linnaeus, 1758)

3. Slellaria Solaris (Linnaeus, 1767)

4. Tibia insulaechorab (Roding, 1798)

5. Stromhus decorus persicus (Swainson, 1821)

6. Neuerita didyma (Roding, 1798)

V Finis gracilis (Suwerl>\ . 1825)

8. Rapana rapiformis (Born, 1778)

9. Inqui.stor griffithi (Gray, 1834)

10. Siphonaria basseinensis (Melvill, 1893)

11. Anadara antiquata (Linnaeus, 1758)

12. Striarca sculpdlis (Reeve, 1857)

13. Pinna murirnln (Linnaeus, 17fiS)

Vol. 99(1)

January 30, 1985

THE NAUTILUS 21

14. Pinctada radiata (Leach, 1814)

15. Pteria marmorata (Reeve, 1857)

16. Isogonomon legumen (Gmelin, 1791)

17. Malleus regulus (Forskal, 1775)

18. Placuna placenta (Linnaeus, 1758)

19. Trachycardium. enode (Sowerby, 1840)

20. Gari occidens (Gmelin, 1791)

21. Bassina callophyla (Philippi, 1836)

22. Marcia hiantina (Lamarck, 1818)

23. Paphia gallus (Gmelin, 1791)

24. Periglypta reticulata (Linnaeus, 1758)

The only previously published work on the

area was by Ahmed (1975) which did not include

the newly recorded species under consideration.

I wish to thank Dr. R. Tucker Abbott of

American Malacologists Inc. for checking the

identifications and reviewing the manuscript. I

also wish to thank Dr. A. Al-Hashimi of the

Kuwait Institute for Scientific Research, Dr. S.

A. Darmonian and Dr. S. D. Salman of the

Marine Science Centre, University of Basrah,

for lending me their specimens.

LITERATURE CITED

Ahmed, M. M. 1975. Systematic Study on Mollusca from

Arabian Gulf and Shatt Al-Arab, Iraq. Centre for Arab

Gulf Studies, University of Basrah, Iraq. pp. 78.

Allouse, Bashir E. 1956. A Bibliography on the Inverte-

brate Fauna of Iraq and Neighbouring Countries. I.

Molluscs. Publication no. 8, Iraq Natural History Museum.

32 pp.

DISTRIBUTION OF THE SNAIL, MELAMPUS BIDENTATUS, AND

THE MUSSEL, GEUKENSIA DEMISSA, ALONG THE

PATAGUANSET ESTUARY (CONNECTICUT) IN RELATION TO

SALINITY AND OTHER TIDAL MARSH INVERTEBRATES

Paul E. Fell and John H. Williams

Department of Zoology

Connecticut College

New London, CT 06320

ABSTRACT

A survey was made of the tidal marshes along the Pataguanset Estuary in

eastern Connecticut to determine the distributions of Melampus bidentatus Say,

Geukensia demissa Dillwyn and a few other invertebrates that are often asso-

ciated with these mollusks. Salinity conditions at six stations located along the

length of the estuary were examined, and an attempt was made to relate the distri-

bution of these animals to salinity. The high marsh species, Melampus bidentatus,

Orchestia grillus and Philoscia vittata, and the low marsh fiddler crab, Uca

minax, were distributed from the head of the estuary to its mouth. Geukensia

demissa and Uca pugnax, which also inhabit the. low marsh, were absent at the

head of the estuary where salinity sometimes falls to 0°/00, but they were present in

the marshes downstream. Toward the upstream extent of their distributions, the

population densities of both Melampus and Geukensia sharply declined. The

distributions of these mollusks were consistent with their known salinity

tolerances, but it is not yet known to what extent salinity is a determining factor.

Although the general community structure of

tidal marshes is well-known (Teal, 1962; Day et

al, 1973; Nixon and Oviatt, 1973; Subrahman-

yam et al, 1976; Fell et al, 1982), relatively little

information exists concerning the distribution

of tidal marsh invertebrates in relation to salin-

ity. Tidal marshes frequently extend far up

estuaries, and consequently salinity may be an

important factor influencing the occurrence of

animals within such marshes. Most of the few

22 THE NAUTILUS

January 30, 1985

Vol. 99(1)

previous studies on the relationship between

salinity and the distribution of tidal marsh in-

vertebrates have dealt with only a single or two

closely related species (see Daiber, 1977 and

1982 for reviews). Therefore almost no informa-

tion is available on how salinity may influence

community structure as a whole.

A number of studies of tidal marsh mollusks

have focused on the high marsh snail, Melampus

hitlnita/us Say, or the low marsh mussel, Geu-

kensia (formerly in Modiolus) demissa Dillwyn.

In general surveys of the Delaware Bay and

Chesapeake Bay areas, Melampus (Wass et al,

1972; Leathern and Maurer, 1975; Parker, 1976)

and Geukensia (Wass et al, 1972; Maurer et al,

1974) were found to have an upper meso-and

polyhaline distribution. Parker (1976) showed

that although Melampus occurred in regions

which exhibit a wide range of salinity, its popu-

lation density was low where salinity was less

than about 10°/oo. Kerwin (1972) investigated

the distribution of Melampus along an estuary in

Virginia; but this snail did not occur in large

numbers at any of the sampling stations, sug-

gesting that factors other than salinity may be

of primary importance in limiting its abundance

within that system.

The purpose of the current study was two-

fold: 1) to examine the salinity conditions at six

stations along the length of the Pataguanset

Estuary in eastern Connecticut, and 2) to

describe the occurrence of Melampus bidentatus

and Geukensia demissa in relation to salinity

and to the distribution of several other tidal

marsh invertebrates.

LONG ISLAND SOUND

FIG. 1. The Pataguanset Estuary. Tidal marshes are in-

dicated by stippling. Salinity sampling stations are

designated by their distance in kilometers from the head of

the estuary. Invertebrate sampling stations are shown by

letters (A to F). E is Watts Island.

Study Site; Methods

The Pataguanset Estuary is located in eastern

Connecticut and opens into Long Island Sound

to the west of Niantic Bay from which it is

separated by Black Point. The estuary, which is

about 3.5 km long, is bordered by tidal marshes

and on the south by the large tidal marsh Watts

Island (Fig. 1). In most places the depth of the

estuary ranges from about 1 to 2 m at high tide.

Extensive beds of widgeon grass, Ruppia mari-

tima, cover the tidal flats of the lower estuary in

the region extending from about 1 to 3 km from

the head. Water temperatures along the estuary

reach about 25°C during the summer and fall

below 0°C during the middle of the winter when

much of the estuary may be covered by ice.

Six stations were established along the

estuary for studying salinity. These were

located at 0.5 to 0.7 km intervals from the head

of the estuary to a region near its mouth (Fig. 1).

During a period extending from late spring

through early fall of 1981 and June through

August of 1982, surface and bottom salinities at

high water of spring tides were determined

every 2 weeks. Twice, once in late June and

again in late July 1981, salinities were recorded

at about hourly intervals covering half of a tidal

cycle from low to high tide. Salinities were

Vol. 99(1)

January 30, 1985

THE NAUTILUS 23

measured in the field with a Goldberg refrae-

tometer (American Optical Co.). A few deter-

minations of soil water salinities in the high

marsh were made after squeezing the water

from samples of peat and filtering the water

through Whatman no. 1 filter paper.

Previous studies on the distribution and abun-

dance of Melampus hidentatus on Watts Island

in the Pataguanset Estuary and on other Con-

necticut tidal marshes have shown that this snail

occurs at high densities in areas of the high

marsh covered by Spartina patens, stunted

Spartitai (litem iflont and .1 uncus gcrardi (Fell

et al, 1982 and unpublished observations). For

this study it was decided to sample Melampus in

S. patens and Juncus because of the abundance

of one or both of these plants in marshes along

the entire estuary. During the summer of 1981

Melampus was studied at six stations (Fig. 1).

The population density of this snail was deter-

mined using a 50 cm square wooden frame, 9 cm

high, which was tossed onto the marsh in areas

of chosen plant cover and at distances of about 2

to 50 m from the water. The vegetation within

the frame was clipped at the surface of the peat

and all of the snails were collected and

enumerated. At the same time the presence of

two other high marsh invertebrates, Philnseia

vittata (isopod) and Orchestia grillus

(amphipod), was noted. The number of quadrats

examined at each station is presented in Table 2.

The abundance of Melampus, Philoscia and

Orchestia at the three stations along the upper

estuary was studied in greater detail during the

summer of 1982. For this purpose 5 transects

running perpendicular to the river bank and

situated 15 m apart were set out at each site.

Each transect was 25 m long, beginning at the

lower edge of the high marsh; and six 50 cm

square quadrats placed 5 m apart were exa-

mined along each transect. Sampling was done

during June, July and August at all three sta-

tions. Transect sampling was used to eliminate

bias in the selection of sampling sites.

The population size of Geukensia demissa was

estimated at each of 5 stations during 1981 by

counting the number of animals within five 5.5

m transects which extended along the banks of

the estuary, except at station E (Watts Island)

where the transects were located along a tidal

creek. The width of the transects (ca 1 to 2 m)

extended from the edge of the water at low tide

to the upper edge of the tall Spartina alter-

niflora zone. Sampling was done along sections

of both banks to assure a representative sample.

In addition, the relative abundance of the fiddler

crabs, Uca minax and Uca pugnax, was deter-

mined in these areas by digging from 50 to

about 70 crabs from their burrows at low tide.

Salinities

There is considerable seasonal variation in

salinity at stations in the upper estuary. For ex-

ample, the surface salinity at the head of the

estuary (St. 0) during high water of spring tides

ranged from 0°/oo during early June to more

than 20°/oo during late summer of 1981 (Fig. 2).

However, at the head of the estuary the surface

salinity may drop dramatically whenever there

are heavy rains. In mid-September of 1981 the

surface salinity at station 0 during high water of

a spring tide was only 2°/00 due to fresh water

drainage. The range in surface salinities during

high water of spring tides narrowed toward the

mouth of the estuary, and at 1.8 km down-

stream the range was only 24 to 32°/00 over the

period of observation. During the summer of

1982, surface salinities at the 3 stations of the

upper estuary during high water of spring tides

exhibited patterns similar to those of 1981, but

they were often 5 to 10°/oo lower for any par-

ticular time.

Salinities recorded at different times during

the tidal cycle also exhibited substantial changes

35

30-

^25-

Q.

Q.

~ 20 -

>

1 15

<

*" 10 — I

5

0

FIG. 2. Surface salinities at four stations along the upper

Pataguanset Estuary during high water of spring tides in

1981. The stations are designated by their distance in

kilometers from the head of the estuary.

24 THE NAUTILUS

January 30, 1985

Vol. 99(1)

at stations in the middle and upper regions of

the estuary (Fig. 3). At the station 1.1 km from

the head of the estuary, the surface salinity

ranged from 3°/oo at low water to 20°/oo at high

water during neap tides in late June and late

July of 1981. As would be expected, the surface

salinities at the head of the estuary were fre-

quently much greater during high water of

spring tides than during the same period of neap

tides (Figs. 3 and 4). Often the salinity at the

surface and that at the bottom were identical or

very similar; however, occasionally stratifica-

tion was noted at the stations of the upper

estuary. The difference between surface and

bottom salinities at any given station usually did

not exceed 10o/oo and was greatest during high

tide. However, when a perigee spring tide oc-

curred during a period of heavy rain (16 Sept.

1981), the surface salinity at the head of the

estuary was 2°/oo at high water while the bottom

salinity was 25°/00.

On two occasions the salinity of the water

actually flooding the high marsh of the upper

estuary was measured and found to be about the

same as the surface salinity in the channel. How-

ever, the salinity of the water just above the

peat was somewhat different. For example,

once when station A was flooded to a depth of

about 20 cm the salinity at the surface was 2°/00,

as it also was in the channel, but close to the

peat the salinity was 5 to 7°/00.

In late June and again in late July of 1981 the

salinity of the soil water of the high marsh was

measured at stations in the upper estuary dur-

ing low tide. The soil water had a salinity of 7 to

16°/00 near the head of the estuary and exhibited

progressively high salinities at stations toward

the mouth (Table 1).

Animal Distribution

Melarrvpus bidentatus was found at all stations

along the estuary (Table 2). However, it was less

abundant in the brackish marshes near the head

of the estuary than in the marshes toward the

mouth. Another pulmonate snail, Succirwa

wilsoni Lea, which is typically found in fresh-

35 -

30

25-

«»■ 20

Q.

t ,5"

z

10 -

5

0-

• A

-I

HOURS

FIG. 3. Surface salinities at six stations along the Pataguanset Estuary during the flooding phase of

the tidal cycle. The stations are designated by their distance in kilometers from the head of the

estuary. Solid circles joined by continuous lines show salinities during part of a neap tidal cycle on 22

July 1981; open triangles indicate the low tide and high tide values during a neap tide on 23 June

1981 ; and open circles joined by broken lines show salinities at station 0 on 5 August 1981. LT = low

tide.

Vol. 99(1)

January 30, 1985

THE NAUTILUS 25

50

JO

20

A 1981 N = 40

B 1981 n 917

C 1981 N: 277!

-I — I — I — I — 1

Z 50

30

2 0

A 1982 N 4.'

B 19 8 2 . N .- 2 5 3

5 7

II 13

— i — l — l — i — i — i — i — | — i — i — i

3 5 7 9 11 13

SHELL LENGTH (mm)

C 1982 _ n: 1231

7 9 II 13

FIG. 4. Size frequency distribution of Melampus bidentatus at 3 stations along the upper

Pataguanset Estuary during 1981 and 1982.

TABLE 1. Soil water salinities at stations in the upper

Pataguanset Estuary during periods of neap tides.

water marshes, occurred together with Melam-

pus at stations A and B. The vegetation in the

higher regions of these brackish marshes con-

sisted of Juncus gerardi and Spartina patens

mixed with Solidago sempervirens, Potentilla

anserina, Gerardia maritima, Panicum virga-

tum and other species. Downstream the num-

bers of Melampus increased until at 1 km or

more from the head high densities of this snail

were found in relatively pure stands of Juncus

gerardi and of Spartina patens. Two inverte-

brates that are normally associated with Melam-

pus in salt water marshes, Philoscia vittata and

Orchestia grillus, (Fell et al, 1982) were also

distributed all along the Pataguanset Estuary,

including the brackish marshes at its head

(Table 2).

Although the surveys of 1981 and 1982 were

in agreement in showing a progressive decline

in the population density of Melampus in the

marshes of the upper estuary, the density of this

snail at particular stations was much lower dur-

ing the second summer (Table 3). In addition,

during 1982 there was also a marked reduction

in the proportion of smaller individuals (Fig. 4).

It is not known whether these changes were

related to the lower salinities occurring during

1982 or to other factors such as high winter

mortality.

Geukensia demissa did not occur at the head

of the estuary. Only a few small mussels were

observed 0.5 km below this point, but at 1 km or

more from the head these animals were moder-

ately abundant (Table 3). Fiddler crabs often

occur together with Geukensia in the low marsh.

Two species of fiddler crab, Uca minax and Uca

pugnax, were found; and one or both species

were present at stations all along the Pataguan-

set Estuary. Only Uca minax occurred at the

head of the estuary and this species was the

dominant fiddler crab at the station 0.5 km

downstream. However, at all of the lower sta-

tions Uca pugnax predominated. The distribu-

tion of this fiddler crab was essentially the same

as that of Geukensia.

26 THE NAUTILUS

January 30, 1985

Vol. 99(1)

TABLE 2. Abundance, no. per0.25mJ (mean ± S.D.. range), of high marsh invertebrates along the Pataguanset Estuary

in Connecticut. N = no. of quadrats examined.

TABLE 3. Distribution of low marsh invertebrates along

the Pataguanset Estuary in Connecticut during the summer

of 1981 (number of Geukensia per 5x 5.5m transects).

Discussion

Geukensia demissa was moderately abundant

in the lower portions of the Pataguanset

Estuary where the salinity of the water at high

tide probably only rarely drops much below

10°/oo. On the other hand, it was absent from the

marsh at the head of the estuary and was pre-

sent in only small numbers 0.5 km downstream.

At these stations the surface salinities at high

tide were sometimes as low as 0 to 2°/00. Uca

pugnax had a similar distribution, but Uca

minax was abundant at stations along the banks

of the upper estuary. Geukensia can survive and

remain active at salinities as low as 8°/00, but

evidently is unable to tolerate prolonged sub-

mergence by water of salinities below about 5°/00

(Wells, 1961; Lent, 1969; Pierce, 1970; Maurer

et al, 1974). Similarly, Teal (1958) has shown

that Uca pugnax is less tolerant of low salinity

than is Uca minax, succumbing within a few

days if submerged in water with a salinity of

7°/0o or lower (LD50 =1.5 days at 0°/oo and 3 days

at 7"/00). Eurthermore, when given a choice be-

tween fresh water and 30°/oo sea water, Uca

pugnax usually chose sea water while lira minax

usually chose fresh water. The predominance of

Uca minax in regions of low salinity and of Uca

pugnax in regions of high salinity has been

observed in a number of marsh systems (Teal,

1958; Kerwin, 1971; Miller and Maurer, 1973).

Competition between these 2 species of fiddler

crabs, as well as other factors, undoubtedly also

influence their distribution (Teal, 1958; Miller

and Maurer, 1973; Daiber, 1977). The fact that

Geukensia demissa and Uca pugnax have similar

salinity tolerances and exhibit essentially the

same distribution along the estuary lends

strength to the hypothesis that salinity may be

an important factor determining their distribu-

tion within this system.

Melampus bidentatus was found all along the

Pataguanset Estuary, as were Orchestia grillus

and Philoscia vittata. The high marsh is basical-

ly a terrestrial environment most of the time,

but it is regularly flooded by spring tides. Conse-

quently, the salinity of the estuarine waters

could be expected to exert less of an influence on

the distribution of animals inhabiting this region

than on those of the low marsh which is inun-

dated more often and for longer periods. On the

other hand, the density of Melampus was lower

in the brackish marshes of the upper estuary

and this may be related, at least in part, to the

lower salinity of the soil water and/or more

probably of the waters of inundation. Not only

may low salinity have a direct influence on the

snails but it may also act indirectly through its

effects on the vegetation which is different in

the brackish marsh. The observations of Parker

(1976) further support this suggestion. In a

study of 12 sites along the New Jersey and

Delaware sides of Delaware Bay and 4 stations

along the Broadkill River in Delaware, he also

found that Melampus occurs in brackish

marshes but that its population density is low

where the salinity is less than about 10°/oo.

Along a tributary of the York River in Virginia,

Melampus was absent from marshes in regions

where the mean surface salinity was below 4°/oo

Vol. 99(1)

January 30, 1985

THE NAUTILUS 27

and was present in only small numbers in

marshes located toward the mouth (Kerwin,

1971 and 1972). In this system it appears that

other factors besides salinity may be of major

importance in limiting snail density.

Melampus adults are remarkably tolerant of

submergence in water ranging in salinity from

full strength sea water to fresh water. They

were found to survive total submergence in

fresh water for a least one day at 20 °C and for

at least 8 days at 10°C (Price, 1980; McMahon

and Russell-Hunter, 1981). Melampus possesses

a planktonic larva (Russell-Hunter, Apley and

Hunter, 1972) which is also tolerant of low

salinities (Parker, 1976). The larvae are highly

active at salinities ranging from 15 to 40o/oo,

slightly less active at 10°/oo and much less active

at 5°/00. About 90% of 2-day-old larvae were

observed to survive for at least 10 hrs. in

salinities ranging from 2.5 to 40°/oo, but none

survived that long in fresh water (Parker, 1976).

Although the distributions of Melampus biden-

tatus and Geukensia demissa along the

Pataguanset Estuary are consistent with the

salinity tolerances of these animals determined

by laboratory experiments, it is not yet known

whether salinity is, in fact, a major factor deter-

mining the distribution and abundance of these

animals. Among other factors that may be im-

portant are predation, composition of the sub-

stratum and flooding regime. Future studies

should focus on more precisely defining the con-

ditions which actually exist in various regions of

the marsh system and on how these conditions

affect all stages of the life history of the animals

which live there. This will require that field

measurements be made at frequent intervals, if

not continuously, throughout the year and that

field studies be accompanied by extensive

laboratory experiments. In most laboratory

studies, the effects of continuous exposure to a

particular set of conditions are examined.

However, in the marsh flooding is periodic, and

therefore it would be desirable to look at the ef-

fects of submersion by water of different

salinities under regimes comparable to those

that would be experienced by animals in the

field. Until such comprehensive studies have

been carried out, it will not be possible to make

really meaningful statements concerning the

causative factors which result in the observed

distributional patterns.

Acknowledgments

Appreciation is expressed to Mary Ann Tilton,

Elizabeth Brown, Mark Pereira, Kenneth

Cadigan, Richard Orsen and Nanette Brodeur

for assistance with the field work and to Dr.

Dorothea Franzen for identifying Succinea

wilsoni. This study was supported by grants

from the Andrew Mellon and Seth Sprague

Foundations.

LITERATURE CITED

Daiber. F. C. 1977. Salt-marsh animals: distribution related

to tidal flooding, salinity and vegetation. In. V. J. Chap-

man, ed., Ecosystems of the World 1. Wet Coastal Ecosys-

tems. Elsevier Sei. Publ. Co., Amsterdam, Oxford, New

York, pp. 79-108.

1982. Animals of the Tidal Marsh. Van

Nostrand/Reinhold Co., New York, 422 pp.

Day, J. W. Jr., W. G. Smith, P. R. Wagner and W. C. Stowe.

1973. Community structure and carbon budget of a salt

marsh and shallow bay estuarine system in Louisiana.

Publ. No. LSU-5G-72-04, 77 pp.

Fell, P. E., N. C. Olmstead, E. Carlson, W. Jacob, D.

Hitchcock and G. Silber. 1982. Distribution and abundance

of macroinvertebrates on certain Connecticut tidal

marshes, with an emphasis on dominant molluscs.

Estuaries 5:234-239.

Kerwin, J. A. 1971. Distribution of the fiddler crab (Uca

minax) in relation to marsh plants within a Virginia

estuary. Chesapeake Set. 12:180-183.

1972. Distribution of the salt marsh snail

(Melampus bidentatus Say) in relation to marsh plants in

the Poropotank River Area, Virginia. Chesapeake Sci.

13:150-153.

Leathern, W. and D. Maurer. 1975. The distribution and

ecology of common marine and estuarine gastropods in the

Delaware Bay area. The Nautilus 89:73-79.

Lent, C. M. 1969. Adaptations of the ribbed mussel, Modio-

lus demissus (Dillwyn), to the intertidal habitat. Amer.

Zool. 9:283-292.

Maurer, D.. L. Watling and G. April. 1974. The distribution

and ecology of common marine and estuarine pelecypods

in the Delaware Bay area. The Nautilus 88:38-45.

McMahon, R. F. and W. D. Russell-Hunter. 1981. The

effects of physical variables and acclimation on survival

and oxygen consumption in the high littoral salt-marsh

snail, Malampus bidentatus Say. Biol. Bull. 161:246-269.

Miller, K. G. and D. Maurer. 1973. Distribution of the fiddler

crabs, Uea pugnax and Uca minax, in relation to salinity in

Delaware rivers. Chesapeake Sci. 14:219-221.

Nixon, S. W. and C. A. Oviatt, 1973. Ecology of a New-

England salt marsh. Ecol. Monogr. 43:463-498.

Parker, N. H. 1976. The distribution, growth and life history

of Malampus bidentatus (Gastropoda: Pulmonata) in the

Delaware Bay region. Master's Thesis. Univ. Delaware.

65 pp.

28 THE NAUTILUS

January 30, 1985

Vol. 99(1)

Pierce, S. K. ,Ir. 19T0. The water balance of Modiolus

(Mollusca: Bivalvia: Mytilidae): osmotic concentrations in

changing salinities. Comp. Biochem. Physiol. 36:521-533.

Price, C. H. 1980. Water relations and physiological ecology

of the salt marsh snail, Melampus bidentatus Say. Jour.

Exp. Mar. Biol. Ecol. 45:51-68.

Russell-Hunter, W. D., M. L. Apley and R. D. Hunter. 1972.

Early life-history of Melampus and the significance of

semilunar synchrony. Biol. Bull. 143:623-656.

Subrahmanyam, C. B., W. L. Krucznski and S. H. Drake.

1976. Studies on the animal communities in two north

Florida salt marshes part II. macroinvertebrate com-

munities. Bull. Mar. Sci. 26:172-195.

Teal, J. M. 1958. Distribution of fiddler crabs in Georgia

salt marshes. Ecology 39:185-193.

1962. Energy flow in the salt marsh ecosystem

in Georgia. Ecology 43:614-624.

Wass, M. L. et al. 1972. A check list of the biota of the lower

Chesapeake Bay. Spec. Sci. Rep. No. 65 Virginia Inst.

Mar. Sci. pp. 1-290.

Wells, H. W. 1961. The fauna of oyster beds with special

reference to the salinity factor. Ecol. Monogr. 31:239-266.

TWO NEW SPECIES OF LYRIA FROM THE

WESTERN ATLANTIC (GASTROPODA: VOLUTIDAE)

William K. Emerson

Department of Invertebrates

American Museum of Natural History

New York, New York 10024

ABSTRACT

Lyria leonardi n. sp. and Lyria russjenseni n. sp. are described from recently

collected specimens obtained in moderate depths off southwestern Puerto Rico.

The former species is also known from the Gulf of Triste, Venezuela, and off

Grenada in the Lesser Antilles on the basis of fragmental specimens. Both taxa

are compared with extant and extinct species q/*Lyria occurring in the Caribbean

region.

The volutid genus Lyria (sensu stricto) is

represented in the Tertiary of the western

Atlantic region by eight extinct species (Hoerle

and Vokes, 1978) and by six extant species, in-

cluding the two new taxa described herein

(Weaver and duPont, 1970; Bayer, 1971). I take

pleasure in naming the new species in honor of

Fred L. Leonard and Russell H. Jensen, who

kindly called my attention to specimens of these

taxa and generously donated their respective

specimens to the American Museum of Natural

History (AMNH) type collection.

The previously known western Atlantic

Recent species that have been referred to the

nominate subgenus are:

1. Lyria beauii (Fischer and Bernardi, 1857),

pi. 9, figs. 1, 2; Dance, 1969, pi. 16, fig. c;

Weaver and duPont, 1970, pi. 4, figs. I, J;

Pointier, 1981, pi. 1, figs. 1-4; and Abbott and

Dance, 1982, p. 213, Type locality: Marie-

Galante, Lesser Antilles. Known only from a

few specimens taken in the Lesser Antilles,

most recently from off Guadeloupe Island.

2. Lyria archeri (Angas, 1865), p. 55, pi. 2,

figs. 4, 5; Weaver and duPont, 1970, pi. 7, figs.

G, H; Abbott, 1974, p. 245, fig. 2675 (not L.

beauii); Pointier, 1981, pi. 2, figs. 6-14; Abbott

and Dance, 1982, p. 213. Type locality: Montser-

rat, Lesser Antilles, recently obtained off Marti-

nique (AMNH coll. 183213). R. T. Abbott re-

ports (in lit.) that Lesley Sutty collected speci-

mens in Guadeloupe in 1969. Dall (1907, p. 351)

referred this species to the genus-group taxon

Enaeta H. & A. Adams (1853, vol. 1, p. 167) in

the mistaken belief that the outer lip had similar

labial dentition. In Enaeta. a blunt, tooth-like

projection occurs near the midpoint of the outer

lip near the margin of the labrum, (Hoerle and

Vokes, 1978, p. 115). In Lyria archeri, the edge

of the labrum is weakly serrated and pustule-

like denticles form at the marginal base of some

of the serrations inside the outer lip. These

Vol. 99(1)

January 30, 1985

THE NAUTILUS 29

"teeth" are prominent in the holotype (Weaver

and duPont, 1970, pi. 7, fig. H). As Try on (1882,

p. 104) pointed out, however, the shell of Lyria

archeri somewhat resembles that of the Indo-

Pacific Lyria (L.) ynitraeformis (Lamarck,

1811). This species apparently is not closely

allied to the other living Lyria in the Caribbean

region.

3. Lyria vegai Clench and Turner, 1967, fig.

1; Weaver and duPont, 1970, pi. 6, figs. F, G;

Abbott, 1974, p. 245, fig. 2676; Pointier, 1981,

pi. 1, fig. 5; Abbott and Dance, 1982, p. 214

(holotype illus.). Type locality: "Cabo Rojo, Prov.

Pedernales, Repiiblica Dominicana, Hispaniola",

in a fish trap. Known only from the holotype.

4. Lyria cordis Bayer, 1971, figs. 58 (shell),

59 (living animal), 60 (radula), 61 (a, gross

anatomy; b, operculum); Abbott, 1972, p. 139

(living animal), Abbott, 1974, p. 245, fig. 2677;

Pointier, 1981, pi. 1, fig. 6; Abbott and Dance,

1982, p. 214 (holotype). Type locality: "Carib-

bean Sea, 20 miles ESE of Sto. Domingo, Island

of Hispaniola, 18° 21.0' N, 69° 14.3' W, depth

174 m." Known only from 2 specimens from the

type locality. This is the type species of the

genus-group taxon, Cordilyria Bayer (1971, p.

204). Notwithstanding the fact that axial sculp-

ture occurs only on the first and second post

nuclear whorls in the type species (L. cordis) as

well as in Lyria vegai, and axial costae are

prominent on the body whorl and the earlier

whorls of Lyria beauii, L. russjenseni n. sp. and

L. leonardi n. sp., these five species appear to be

more closely related to each other than to Lyria

archeri. They form a species complex for which

the subgenus Cordilyria is available, if recogni-

tion is subsequently deemed warranted on the

basis of anatomical differences with the Indo-

Pacific Lyria. For the present, Lyria archeri

seems best retained in Lyria (sensu stricto).

The New World representatives of the Cordi-

lyria species complex occur in moderately deep

water in the Caribbean Sea and are rarely found

in collections. All the specimens I have exa-

mined of the two species described here were

dead-collected. Most appear to have been oc-

cupied by hermit crabs, which would account for

the presence of these shells in baited fish traps.

The shells possess one or more octopus drill

holes, suggesting that the specimens were the

victims of octopod predation.

Family Volutidae Rafinesque, 1815

Subfamily Lyriinae Pilsbry and Olsson, 1954

Genus Lyria Gray, 1847

Lyria Gray, 1847, p. 141; type species by

original designation: Voluta nucleus Lamarck,

1811, Recent, Indo-Pacific.

Lyria leonardi new species

Figures 1 to 6

Lyria beauii Fischer and Bernardi, Dall, 1907,

p. 351, fragmental specimen, National Museum

of Natural History (NMNH) 87718, near

Grenada, in 133.5 m. Not Lyria beauii (Fischer

and Bernardi, 1857).

Lyria cf. limata Hoerle and Vokes, Petuch,

1981, p. 331, figs. 75, 76, Golfo de Triste, Vene-

zuela, in 16 m. Not Lyria (L.) limata Hoerle and

Vokes, 1978, p. Ill, pi. 1, figs. 4, 5, Chipola For-

mation, Florida, Miocene.

Diagnosis: Ovately fusiform shell, large for

genus, attaining 100 + (?) mm in length, of 8V2

whorls; axial sculpture of 11 to 14 weakly folded

ribs; color tannish white; spirally banded by ir-

regular squarish blocks of brown below the

suture and with 3 similar spiral bands on the

body whorl; spirally threaded by 6 to 7 brown,

strongly penciled lines on the body whorl, with 1

to 3 similar spiral lines on the earlier post

nuclear whorls; aperture whitish with yellowish

buff submarginal callus within the outer lip.

Description: Shell ovately fusiform; 2V2

smooth nuclear whorls; 6 post nuclear whorls;

first 3 post nuclear whorls with 14 well-defined

axial costae (see Fig. 3); remaining post nuclear

whorls with 11 loosely formed axial ribs; suture

weakly defined; aperture elliptical, more than V2

the height of the shell; outer lip lacking marginal

barbs, thickened internally by a submarginal

lenticular callus; columella with 3 prominent

adapical plications and 9 thread-like lirations,

with the most adapically placed lira best

developed; siphonal fasciole weak, anal sulcus

shallow; operculum and radula unknown. Color,

see diagnosis.

Type locality: off Cabo Rojo, Puerto Rico,

trawled in 500 ± m., ex-E. Flynn Ford coll., ex-

Fred L. Leonard coll., 1981.

Holotype: AMNH no. 213575, from the type

locality; height = 52 mm, width = 21.2 mm.

Here illustrated, Figs. 1, 2 and 3.

Paratype: NMNH no. 820640, R/V John

30 THE NAUTILUS

January 30, 1985

Vol. 99(1)

FIGS. 1-6. Lyria leonardi new species. 1-3, Holotype, AMNH no. 213575; 4-6, Paratype, NMNH no. 820640. 1 and 2 approx-

imately x lVs; 3, early whorls greatly enlarged; 4-6, x 1.

Vol. 99(1)

January 30, 1985

THE NAUTILUS 31

Elliott Pillsbury station P-758 (11° 42.4' N.,

60° 40' W), in 16 m., Golfo de Triste, Venezuela

(see Petuch, 1981, p. 331, figs. 75-76); fragment

lacking pre-body whorls, height = 72.00 mm.

Here illustrated, Figs. 4-6.

Referred specimen: NMNH no. 87718, U.S.

Fish Commission station 2120, in 133.5 m, near

Grenada, Lesser Antilles (see Dall, 1907, p.

351); fragment lacking much of the body whorl,

height = 29.3 mm.

Remarks: The color pattern approaches that

of L. limata Hoerle and Vokes (1978, pi. 1, figs.

5a, 5b), but this smaller, more slender Miocene

species has better developed costae, stronger

and fewer columellar lirations, and possesses

barbs on the outer lip.

Lyria russjenseni new species

Figures 7 to 15

Diagnosis: Shell narrowly fusiform, 8V2

whorls, medium size for genus, attaining 70 +

mm in height; axial sculpture of 12 to 13 ir-

regularly formed ribs; color buff-cream with

small v-markings, spirally banded by broken

blotches of irregular brown squares below the

suture, midway and anteriorly on the body

whorl; bands interrupted by zigzag patterns,

especially at base of the body whorl; outer lip

ringed within by a yellowish buff, submarginal

callus; aperture white.

Description: Shell slender, fusiform; 2V2

smooth nuclear whorls; 6 post nuclear whorls;

axial costae 12 to 13 per whorl, weakly devel-

oped on 1st and 2nd post nuclear whorls (see

Fig. 15); obsolete on 3rd and 4th whorls; promi-

nent on penultimate whorl and body whorl;

suture distinct, weakly channeled; aperture nar-

rowly elongate, about V2 the height of the shell;

interior of outer lip thickened submarginally by

a lenticular callus in mature specimens, lacking

marginal barbs; columella with 3 prominent

adapical plications and 12 to 17 weak lirations

extending into the aperture, terminating in a

more prominent lira at the adapical end in

mature specimens. Siphonal fasciole weak; anal

sulcus narrow and shallow; operculum and

radula unknown. Color, see diagnosis.

Type locality: off La Paguera, Puerto Rico,

taken in a lobster pot by fisherman, 1978, ex-

Miguel Carlo, ex-Russell Jensen coll.

Holotype: AMNH no. 213576, from the type

locality; height = 65.5 mm, width = 26.2 mm.

Here illustrated, Figs. 7, 8.

Paratype A: off Cabo Rojo, Puerto Rico, in a

fish trap, in approximately 244 m., ex-Miguel

Carlo, 1983, Harry G. Lee coll.; height = 71.5

mm, width = 28.8 mm. Here illustrated, Figs. 9,

10, and 15.

Paratype B: off Cabo Rojo, Puerto Rico, in a

fish trap set 8 to 10 miles off shore in approxi-

mately 300 m., mid-1979, ex-Miguel Carlo,

Gregory Curry Sr. coll.; height = 39.4 mm,

width = 17.2 mm.

Paratype C: AMNH no. 213574, same locality

as paratype B, ex-Miguel Carlo, 1979, ex-

Richard Goldberg coll.; height = 26.8 mm,

width = 13.4 mm. Juvenile specimen, here il-

lustrated, Figs. 13, 14.

Paratype D: same locality as paratype B, ex-

Miguel Carlo; Gregory Curry, Sr. coll.; height =

57.7 mm (apex incomplete), width = 25.4 mm.

Here illustrated, Figs. 11, 12.

Paratype E: off Mayaquez, Puerto Rico, in a

fish trap, set in 274 mm; ex-Miguel Carlo, 1982,

Michael Cahill coll.; height = 56 mm, width =

24 mm.

Remarks: This species resembles L. beauii

(Fischer and Bernardi, 1857) in shell morphol-

ogy, but it differs in having less extended axial

ribs on the body whorl, and a distinctive color

pattern. In Lyria leonardi n. sp. the axial ribs

adjoin the suture, whereas in the present species

and L. beauii the ribs are poorly developed at

the suture in mature specimens (Figs. 7-10).

Acknowledgments

In addition to Russell H. Jensen and Fred L.

Leonard, I am indebted to a number of people

for valuable contributions to this study. The fol-

lowing generously provided specimens on loan

and/or contributed pertinent information: Kirk

Anders, Michael Cahill, Miguel Carlo, Gregory

Curry, Sr., C. John Finlay, Mary S. Ford,

Richard Goldberg, Thomas Honker, Harry G.

Lee, Edward J. Petuch, Joseph Rosewater,

John K. Tucker, and Thomas R. Waller. My

AMNH colleagues, Walter Sage, III, Peter J.

Harries, and Stephanie Crooms kindly provided

technical assistance, photography, and the word

processing, respectively.

32 THE NAUTILUS

January 30, 1985

Vol. 99(1)

FIGS. 7-l.r>. Lyria russjenseni nnr spears. 7 and 8, Holotype, AMNH no. 213576; 9, 10, 15, Paratype A, H. G. Lee coll.; 11

and 12, Paratype D, G. Curry, Sr. coll.; 13 and 14, Paratype C. AMNH no. 213574. 7-14 approximately x IVs; 15, early whorls

greatly enlarged.

Vol. 99(1)

January 30, 1985

THE NAUTILUS 33

LITERATURE CITED

Abbott, R. T. 1972. Kingdom of the Seashell, New York,

256 pp.

1974. American Seashells, The Marine Mollusea

of the Atlantic and Pacific Coasts of North America, New

York, 2nd ed., 663 pp., 24 pis., text figs.

Abbott, R. T. and Dance, S. P. 1982. Compendium of Sea-

shells, A Color Guide To More Than 4,200 of the World's

Marine Shells, New York, 411 pp., illus.

Adams, H. and A. 1853[-1854]. The Genera of Recent Mol-

lusea; arranged according to their organization. London,

vol. 1, pp. 1-256, pis. 1-32 [1853]; pp. 257-484, pis. 33-60

[1854].

Angas, G. F. 1865. Descriptions of ten new species of shells,

chiefly from the Australian Seas, Proc. Zool. Soc. London,

pt. 1, pp. 55-58, pi. 2.

Bayer, F. M. 1971. Biological results of the University of

Miami Deep-Sea Expeditions. 79. New and unusual mol-

lusks collected by R/V John Elliott Pillsbury and R/V

Gerda in the tropical western Atlantic. Bull. Mar. Set.,

vol. 21, no. 1, pp. 111-236, 72 figs.

Clench, W. J. and Turner, R. D. 1967. A new species of

Lyria (Volutidae) from Hispaniola. The Nautilus, vol. 80,

no. 3, pp. 83-84, figs. 1-3.

Dall, W. H. 1907. A review of the American Volutidae.

Smithsonian Misc. Coll., vol. 48, no. 3, pp. 341-373.

Dance, S. P. 1969. Rare Shells. Berkeley, 128 pp., 25 pis.

Fischer, P. and Bernardi, A. C. 1857. Descriptions d'especes

nouvelles. Jour. ConchyL, vol. 5, no. 3. pp. 292-300,

pis. 8, 9.

Hoerle, S. E. and Vokes, E. H. 1978. A review of the

volutid genera Lyria and Falsilyria (Mollusea: Gastro-

poda) in the Tertiary of the Western Atlantic. Tulane

Studies Geol. and Paleont, vol. 14, no. 3, pp. 105-130,

pis. 1-5.

Petuch, E. J. 1981. A relict Neogene caenogastropod fauna

from northern South America. Malacologia, vol. 20, no. 2,

pp. 307-347, figs. 1-130.

Pilsbry, H. A. and Olsson, A. A. 1954. Systems of the Voluti-

dae. Bull. Amer. Paleont., vol. 35. no. 154, pp. 1-37,

pis. 1-4.

Pointier, J. P. 1981. Les Lyria des Caraibes. Xenophora

(Bull. Club Francais Collectionneurs de Coquillages), no.

3, May, pp. 13-15, 4 text figs., 2 pis.

Tryon, G. W., Jr. 1882. Family Volutidae, Manual of

Conchology, ser. 1, vol. 4, pp. 73-105, pis. 22-31, Phila-

delphia.

Weaver, C. S. and duPont, J. E. 1970. The Living Volutes,

A Monograph of the Recent Volutidae of the World.

Delaware Mus. Nat. Hist. Monogr. Ser. no. 1, 375 pp.,

78 pis.-, 43 text figs.

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THE

NAUTILUS

ISSN 0028-1344

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Museum of Comparative Zoology

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CONTENTS

THE

NAUTILUS

Volume 99, numbers 2-3 - April 29, 1985

ISSN 0028-1344

William G. Lyons

Chaetopleura staphylophera (Polyplaeophora: Chaetopleuridae), a New Species

from the Southeastern United States and Bahamas 35

Jose Henrique N. Leal and Arnaldo C. dos Santos Coelho

Arenejlexispina, a New Species (Gastropoda: Liotiidae) from Off Eastern Brazil 45

Gary L. Pace and Ernest J. Szuch

An Exceptional Stream Population of the Banded Applesnail,

Viviparus georgianus, in Michigan 48

John W. Ropes

Modern Methods Used to Age Oceanic Bivalves 53

Anthony D'Attilio and Barbara W. Myers

Two New Species oiFavartia from the West Pacific Ocean (Gastropoda: Muricidae) 58

Paul S. Mikkelsen

A Rapid Method for Slide Mounting of Minute Radulae,

with a Bibliography of Radula Mounting Techniques 62

Scott E. Belanger, Jerry L. Farris, Donald S. Cherry, and John Cairns, Jr.

Sediment Preference of the Freshwater Asiatic Clam, Corbicvlafluminea. . . .

.66

C. John Finlay

A West Indian Columbellid New to the Genus Steironepion 73

Neil C. Hulings

Activity Patterns and Homing in Two Intertidal Limpets, Jordan Gulf of Aqaba 75

Fred G. Thompson and Emilye L. Huck

The Land Snail Family Hydrocenidae in Vanuatu (New Hebrides Islands),

and Comments on Other Pacific Island Species 81

Ralph W. Taylor

Comments on the Distribution of Freshwater Mussels (Unionacea) of the

Potomac River Headwaters in West Virginia 84

J. Gibson-Smith and W. Gibson-Smith

A Second Melampid (Pulmonata: Basommatophora) from

the Early Miocene of Venezuela 87

Deaths iv, 80 Meetings 44, 80

in

STATEMENT OF OWNERSHIP, MANAGEMENT AND CIRCULA-

TION (Required by) Act of October 23, 1962: Section 4396. Title

39. United States Code, and postal regulation 132-622.

1 Title of publication: THE NAUTILUS.

2. Date of filing: October 17, 1984.

3. Frequency of Issue: Quarterly (4 per year).

4. Location of known office of publication: 2208 South

Colonial Dr., Melbourne, FL 32901.

5. Location of Headquarters of General Business Offices of

the Publishers: 2208 South Colonial Dr., Melbourne, FL

32901

6. Names and addresses of publisher, editor, and manag-

ing editor: Publisher, American Malacologists, Inc., P.O.

Box 2255, Melbourne, FL 32901. Editor, R. Tucker Abbott,

P.O. Box 2255, Melbourne, FL 32901. Business Manager,

Mrs. Cecelia W. Abbott, P.O. Box 2255, Melbourne, FL

32901.

7. Owner: American Malacologists, Inc., P.O. Box 2255,

Melbourne, FL 32902.

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holders owning or holding 1 percent or more of total

amount of bonds, mortgages or other securities: none

Extend and Nature of Circulation:

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1 . Sales through dealers and carriers,

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and back start subscription copies

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I certify that the statements made by me above are correct and

complete.

(signed) R. Tucker Abbott, Editor

Faye B. Howard, 1907 - 1984

The Santa Barbara Museum of Natural His-

tory recently lost one of the driving forces

behind the development of malacology in the

Department of Invertebrate Zoology. Delia

Faye Ballou was born at home in Grumpier,

North Carolina on February 15, 1907. At the

age of ten her family moved to California. She

attended Fullerton City College and the Univer-

sity of California, Berkeley where she was intro-

duced to shells by her neighbor, John Jones.

Beginning in 1932 until shortly before her

death, Faye engaged in private research in con-

chology. In 1961 she was appointed as a

Research Associate in Conchology at the

Museum. From 1961 to 1968 she 'personally

funded the position of Assistant in Conchology

at the Museum. During the same period Faye

organized, financed and led six major expedi-

tions to West Mexico to study and collect mol-

lusks. With the impetus of Faye's enthusiasm

and support, the Santa Barbara Malacological

Society was founded in 1962. She served on the

Editorial Board of the Society's publication, the

Tabulntu, from 1967 to 1974. Faye was a

member of the Conchological Club of Southern

California for 54 years and was also a member of

the Hawaiian Malacological Society. She

authored a total of 22 publications on mollusks

and famous malacologists. She described two

new species of marine gastropods, and had four

new species and one new subspecies named in

her honor. She died December 14, 1984. Faye's

dream of establishing a major center for the

study of mollusks in Santa Barbara will become

a reality, supported by her large collection and a

bequest which she leaves to the museum. This

legacy will forever preserve her memory but will

never fill the void she leaves behind.

- F. G. Hochberg

ir

THE NAUTILUS - ITS 99th YEAR

(an editorial)

77/r Nautilus had its beginnings in Philadelphia on July 1,

1886. That means we shall be celebrating our KMlth anniversary

next year, in 1986. We began as The Conchologist's Exchange,

with W. D. Averell as editor. When Henry A. Pilsbry took over

as the chief editor in 1889, the name was changed at the third

volume to The Nautilus. Since then, in the span of 96 years,

there have been only three chief editors- Henry A. Pilsbry, H.

Burrington Baker and myself.

It is time for an editorial. Its purpose is to invite our friends

and subscribers, both professional malacologists and private

amateur collectors, to participate in our celebration of 100 years

of service to the malacological community. We will briefly

review the history of the journal, but our main theme will be a

memorial tribute to the late William J. Clench and to his former

student, the late Joseph Rosewater. The 100th volume will

largely consist of scientific articles on mollusks, many by Bill

Clench's students, that acknowledge his help or that may name a

new taxon in his honor. Additionally, we hope to do the same for

Joe Rosewater. Personal reminiscences about either malacolo-

gist will be most welcome.

Although The Nautilus is independent of any university or

museum, it has existed only because of the support from in-

dividual malacologists and private collectors. During my -7

years as an editor, I have been most appreciative of this support.

and I hope that the next editor, who ever he or she may be, will

carry on in the same cooperative spirit.

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 35

CHAETOPLEURA STAPHYLOPHERA (POLYPLACOPHORA:

CHAETOPLEURIDAE), A NEW SPECIES FROM THE

SOUTHEASTERN UNITED STATES AND BAHAMAS

William G. Lyons

Florida Department of Natural Resources

Bureau of Marine Research

St. Petersburg, FL 33701

ABSTRACT

Chaetopleura staphylophera n. sp.,from off North Carolina, the Bahamas, and

both Florida coasts, differs from other western Atlantic Chaetopleura by posses-

sion of considerably larger, nonaligned pustules on end valves and lateral areas of

intermediate valves, and from the west American C. gemma in that pustules of

that species are aligned in radial rows. Relegation o/Calloplax Thiele, 1909. to

synonymy with Chaetopleura Shuttleworth, 1853. is recommended.

Investigations of continental shelf fauna of

relatively deep waters off Florida and adjacent

areas have revealed a previously unknown

species of the genus Chaetopleura Shuttleworth,

1853, which is here described. Questions regard-

ing generic placement of this and another spe-

cies prompted review of characters of Chaeto-

pleura and of the genus Calloptax Thiele, 1909.

Most specimens examined during this study

were collected during the Hourglass Cruises off

central west Florida (Joyce and Williams, 1969),

a survey of rock shrimp off northeast Florida

(Kennedy et al., 1977), and a study of the fauna

of Oculina reefs off central east Florida (Avent

et al., 1977; Reed et al., 1982). The first two pro-

grams were conducted by the Florida Depart-

ment of Natural Resources Bureau of Marine

Research utilizing the R/V Hernan Cortez, and

the third was conducted by Harbor Branch

Foundation utilizing the submersible Johnson-

Sea-Link (JSL). Specimens are housed in the

U.S. National Museum of Natural History,

Smithsonian Institution (USNM), Washington,

DC; the Academy of Natural Sciences of Phila-

delphia (ANSP), Pennsylvania; the American

Museum of Natural History (AMNH), New

York; the Brevard Museum, Inc. (BMI), Cocoa,

Florida; the British Museum (Natural History)

(BMNH), London; the California Academy of

Sciences (CAS), San Francisco; the Harbor

Branch Foundation (HBF; museum prefix

IRCZM), Ft. Pierce, Florida; the University of

North Carolina Marine Science Institute (UNC),

Morehead City; and the Florida Department of

Natural Resources Bureau of Marine Research

(FDNR; museum prefix FSBC I), St. Peters-

burg. Because nearly all specimens were curled

to some extent, measurements of total length

are to the nearest 0.5 mm; individual valve-

lengths are measured at the midline.

Chaetopleura staphylophera, new species

(Figs. 1-14. li.s)

ICalloplax janeirensis: Porter. 1974, p. 302 [mm C. janei-

rensis (Cray, 1828)].

Chaetopleura sp. Lyons, 1982, p. 39.

Holotype: Length 15.5 mm; Hourglass Station

M; 26°24'N, 83°43'W, approximately 92 nmi

west of Sanibel Island Light, Florida west coast;

73 m depth; 12 April 1966; USNM 842109.

Other material: FLORIDA: 1 paratype, 15.0

mm; Hourglass Station M; 12 April 1966; FSBC

I 31757.- 1 paratype, 17.0 mm; same; 13

November 1966; FSBC I 31759.- 1 paratype,

11.5 mm; Hourglass Station D; 27°37'N,

83°58'W, approximately 65 nmi west of Egmont

Key; 55 m; 4 April 1967; FSBC I 31758.- 1

paratype, dried, curled; Eolis Station 104; off

Fowey Light; 91 m; J. B. Henderson, coll.;

USNM 454682.- 1 paratype, 21.0 mm;

27°13.1'N, 79°58.7'W, 9 nmi ENE of St. Lucie

Inlet; 64 m; 14 April 1973; FSBC I 31760.- 2

paratypes, 11.0, 15.0 mm; JSL Station 2122A;

27°32.8'N, 79°58.8'W, east of Ft. Pierce; 77.4

m; 20 September 1976; IRCZM 61:060. - 2 para-

types, 6.0, 8.5 mm; JSL Station 2125A; same

36 THE NAUTILUS

April 29, L985

Vol. 99(2-3)

r*

Jf

FIGS. 1-8. 1-6, Chaetopleura staphylophera n. sp., paratype, 15.0 mm; west of Sanibel Island, Florida, 73 m; FSBC 1 31757: 1.

valve I; 2, valve IV; 3, valve VIII; 4. valve II; 5, valve VIII. lateral view (all x 15); 6, girdle spicule ( x 220); 7, ' ' xtapkylnphem,

paratype, 16.0 mm; 23. f> nmi east of Port Canaveral, Florida, 73 m; FSBC 1 31761; dorsal girdle scales i ■ 515); 8. same; ven

tral girdle scales ( x 550).

coordinates; 77.7 m; 21 September 1976;

IRCZM 61:061. - 4 paratypes, 1.5-8.5 mm; JSL

Station 2160A; same coordinates; 73.8 m; 2

February 1977; IRCZM 61:062.- 1 paratype,

7.0 mm; JSL Station 2163A; same coordinates;

80 m; 7 February 1977; IRCZM 61:063.- 1

paratype, 1.8 mm; JSL Station 2163B; same

coordinates, depth, and date; IRCZM 61:064.-

1 paratype, 16.0 mm; [?] 28°02'N, 80°26'W, 8

nmi east of Grant; is m; 6 June 1978; BMI

1143.- 2 paratypes, 9.0, 10.0 mm; 28°02.8'N,

79 r.s.o'W. 31.5 nmi SF of Port Canaveral; 73

m; 22 May 1973; ANSP A-10629.- 1 paratype,

12.0 mm; 28°10'N, 80°03'W, 30 nmi ENE of

Melbourne; 53 m; September 1981; AMNH

70. - 2 paratypes, 6.5, 16.0 mm; 28°18.9'N,

79 9 I'W, 23.5 nmi east of Port Canaveral; 73

m; 19 June 1973; FSBC I 31761.- 1 paratype,

13.5 mm; 28°35'N, 80°07'W, 24 nmi ENE of

Cape Canaveral; 61 m; July 1982; BM(NH)

1985007.- 1 paratype, 9.5 mm; 28°37.1'N,

80°04.8'W, 25 nmi FNF of Cape Canaveral: 64

m; 14 August 1973; CAS 056545.- 1 paratype,

18.0 mm; 28°41'-40'N, 80°03'W, 28 mi ENE of

Cape Canaveral; 86-91 m; 23 April 1983; FSB< ' I

30775.- 1 paratype, 13.0 mm; 30 00'N,

80°15'W. 54 nmi FNF of St. Augustine;

73.1-82.2 m; 24 June 1982; FSBC I 30774.

NORTH CAROLINA: 1 paratype. 14.5 nun;

Eastward Station 480; 34'12'N, 76' 05.9'W, SE

,>( Cape Lockout; 73-107 m; 18 March 1969;

UNC 4302.1- GRAND BAHAMA ISLAND: 1

tail valve (viii). 7.3 nun wide. 4.2 mm long; Gold

Rock; 24.1 m; J. N. Worsfold, coll.; July 1981;

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 37

FSBC I 31762. - 1 tail valve (viii), 7.0 mm wide,

3.8 mm long; Tamarind Beach Reef; 46.8 m;

Worsfold collection. - 1 intermediate valve, 7.2

mm wide, 3.1 mm long at jugum; Gold Rock;

26.2 m; Worsfold collection.- 1 intermediate

valve, 9.9 mm wide, 4.5 mm long at jugum;

Indian Cay; 23.0 m; Worsfold collection.

Description: Largest entire specimen 21.0

mm long, 9.5 mm wide, including girdle. Some

paratypes bright orange; holotype and other

paratypes yellow or beige with white stripe on

jugum; stripe sometimes overlain with orange,

anteriorly directed, slender triangle; or, in addi-

tion, with dark brown in central areas of valves

ii, iv, v, vii, and viii. Tegmentum ornamented

with rounded, large pustules (to 300 \xm dia-

meter) and linearly aligned, usually small (to 150

\xm diameter) pustules. Width of tegmentum of

valves of undissected holotype: i = 3 . 6 ; ii = 4.1;

iii = 4.5; iv=4.6; v=4.8; vi = 4.9; vii = 4.5; viii =

3.6 mm. Head valve (i) ornamentation beginning

as radial rows of 3 or 4 small pustules at apex,

thereafter losing alignment but closely situated,

increasing in size toward margin, resulting in

vaguely concentric arcs of pustules of similar

size. Lateral areas of intermediate valves (ii-vii)

with about 30-50 large pustules, seldom if ever

connected, those at anterior margins aligned in

transverse rows, others scattered, all closely

packed, increasing in size toward anterolateral

corners; central areas with as many as 19 or 20

subparallel, occasionally converging, longitu-

dinal rows of small pustules (8-9 rows on holo-

type); pustules of rows increasing in size and

decreasing in numbers toward lateral margins;

as many as 20 small pustules in rows near

jugum; rows usually continuing over jugum of

valves ii and vii, sometimes absent or inter-

rupted at jugum of valves iii-vi; posterior edges

of intermediate valves straight in larger speci-

mens, slightly beaked in smaller specimens, all

slightly peaked (subcarinate) at center. Tail

valve (viii) with mucro slightly elevated, a little

anterior of center, thereafter dropping away

concavely for a short distance and then sloping

gently to posterior margin; jugum and central

areas with parallel rows of small pustules; re-

mainder of valve with large, densely packed

pustules arranged in concentric rows of pustules

of similar size, largest at margin.

Articulamentum white, with light brown or

orange hues evident through strongly excavate

surfaces beneath lateral areas, somewhat less

evident beneath central areas, occasionally with

an orange, longitudinal stripe beneath jugum.

Insertion teeth well defined, relatively sharp,

thickened near slit; slit formula 11-1-8. Sutural

laminae relatively short, broadly rounded ante-

riorly; sinus well defined; on valve viii of 16.0

mm specimen, width of sinus 0.9 mm, width of

sutural laminae 2.4 mm; ratio (relative width of

sinus) 0.375. Eaves solid.

Girdle upper surface paved with small (about

70-75 x 20-35 ^m), ovoid, elongate scales, coarse-

ly striated toward sometimes pointed distal tips,

interspersed with a few glassy spicules up to 350

urn long; girdle outer margin fringed with glassy

spicules of two types, the first slender, blade-

like (30x210 fmi), the other very slender and

small (8-10x55-80 \xm); undersurface paved with

rectangular, transparent scales about 25 x

50-100 jmi, each bearing an outer edge pro-

tuberance that articulates with inner edge con-

cavity of adjacent scale; girdle bridges packed

with slender, blade-like spicules (10 x 1 15 j^m).

Radula of 16.0 mm specimen 5.0 mm long

(31% of total specimen length), with 48 rows of

mature teeth; median tooth broadly rectangu-

lar, about 90 \im wide at anterior blade; major

lateral teeth with tricuspid head 120 ytm long, 80

^m wide.

Variation: The 27 intact specimens range in

length between 1.5 and approximately 21.0 mm.

No pustules are present on two specimens 1.5

and 1.8 mm in length, but a 2.2 mm specimen

(IRCZM 61:062) has single large pustules at

anterolateral corners of each intermediate

valve, indicating that tegmental ornamentation

may begin at about that size. Thereafter, large

pustules of all valves apparently increase in size

and number with increasing size of the animal.

The largest specimen (21.0 mm; FSBC I 31760;

Fig. 14) is severely eroded on all valves, par-

ticularly at the junctions of lateral and central

areas of the intermediate valves. The rows of

small pustules of central areas extend over the

jugum of all valves except iv, which remains

smooth on the posterior half; indications of

19-20 pustule rows are present on some valves.

In lateral areas of the 21.0 mm specimen,

largest pustules tend to occur near the middle,

and pustules nearest the girdle are somewhat

38 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

FIGS. 9-12. Single valves of Chaetopleura staphylophera n.

sp. from sediments, Grand Bahama Island (all x 3.5): 9,

valve VIII; Gold Rock, 24.4 m; FSBC I 31762; 10, valve VIII,

Tamarind Beach reef, 4(1.8 in; 11, intermediate valve; Gold

Rock, 26.2 m; 12, intermediate valve; Indian Cay, 23.0 m.

[Figured specimens ld-12 in Worsfold collection].

smaller and arranged in rough, concentric arcs,

giving the impression of less energetic growth

with advanced age.

The Bahamian specimens consist only of sin-

gle valves (Figs. 9-12), but their tegmental

pustular arrangements are similar to those of

specimens from North Carolina and Florida. If,

as seems likely, the Bahamian specimens repre-

sent the new species, this may indicate that the

species attains greater size than exhibited by

the largest (21.0 mm) entire specimen; width of

the tegmentum of valve viii of that specimen is

only 5.2 mm, whereas that of the largest Baha-

mian specimen is 7.3 mm.

Distribution: Intact specimens of Chaeto-

pleura staphylophera were examined from off

Tampa Bay and Sanibel Island, Florida west

coast; off Fowey Light near Miami; offshore of

St. Lucie Inlet northward to St. Augustine

along the Florida east coast; and southeast of

Cape Lookout, North Carolina. Because all

other Florida specimens were taken from

depths of 53-91 m, the single record from 18 m

(BMI 1143) is questioned. The North Carolina

collection is from "240-350 ft" ( = 73-107 m), so

that specimen may have occurred within the

depth range of the Florida material or in slightly

greater depths. All Bahamian specimens are

from off the southwest coast of Grand Bahama

Island and consist only of single valves collected

by divers from sediments near reefs in 23-47 m

depths, somewhat shallower than the continen-

tal collections.

Etymology: The specific name staphylophera,

from the Greek staphyle (a bunch or cluster of

grapes) and phero (to bear or carry), refers to

the distinctive clusters of large, grape-like

pustules on lateral areas of intermediate valves.

Remarks: Porter (1974: p. 302) listed the

13

14

15

16

17

FIGS. 13 17. 13, Chaetopleura staphylophera n. sp.. holotype, 15.5 mm; west of Sanibel Island. Florida, 73m; USNM 842109;

14, C iaphylophera, paratype, 21.0 mm; 9 nmi ENE of St. Lucie Inlet, Florida, 64 m; FSBC I 3176(1; 15, Chaetopleura

Ua (Say), 12. 1 mm; cast of Hutchinson Island, Florida, 91.5 m; FSB< ' I -".0767, 16. "' 'alloplax" janeirensis (Gray), 18.0

mm; Sand Ke reef, Florida, 1 m; FSBC I 31765; 17. "C "janeirensis, 16.0 mm; Riode Janeiro, Brazil, shallow; FSBC I 31768.

Vol. 99(2-3)

April 29. 1985

THE NAUTILUS 39

North Carolina specimen as ICalloplax janeiren-

.s/.s, and Lyons (1982: p. 39) mentioned an un-

described species of Chaetopleura from the

Bahamas. Both reports were based upon speci-

mens used in this study and which are herein

described.

The new species differs from Cliactuplcura

apiculata (Say, 1834), the only previously

known Chaetopleura species from the eastern

and southern United States, by possession of

much larger, more densely arrayed pustules on

the end valves and on lateral areas of inter-

mediate valves (Figs. 18-20). Additionally, the

major lateral tooth of the radula of C. apiculata

is bicuspid (Fig. 29), whereas that of the new

species is tricuspid (Fig. 28). In areas where the

ranges of the two species overlap latitudinally,

C. apiculata usually (bul not always) occupies

shallower depths than does < '. staphylophera.

Other western Atlantic species of Chaetopleura

are known only from the southern Caribbean or

further south. These include C. candisata

Shuttleworth, 1856 ( = C apiculata. fide Kaas,

1972; Kaas and Van Belle, 1980;' Ferreira,

1983a), from Cuadeloupe, and C. angulata

(Spengler, 1797), C. isabellei (d'Orbigny, 1841),

and <'. spiiiuliisii (Cray, 1828), all from Brazil or

southward to Patagonia. Published descriptions

of the last three species indicate that all possess

tegmental pustules considerably smaller and

more widely spaced than those of the new

species. Chaetopleura carrua Righi, 1970, en-

tirely lacks pustules on end valves and lateral

areas of intermediate valves. Instead, Chaeto-

pleura staphylophera demonstrates a close rela-

tionship to Chaetopleura gemma Dall, 1879, a

west American species which occurs from Van-

couver Island, Canada, to Magdalena Bay, Baja,

California (Burghardt and Burghardt, 1969;

Putnam, 1980). That species lives in depths of

10-40 fms (18-73 m) or more according to Clark

(1982), but Ferreira (1983a) reports the bathy-

metric range as 0-22 m; the reason for this dis-

crepancy is unknown. Like the new species, the

major lateral tooth of the radula of C. gemma is

tricuspid (Dall, 1879: 296, pi. 1, fig. 9). Tegmen-

tum color, size and shape of pustules, and slit

formula (9-12/1/7-8) of C. gemma are also similar

to those of < '. staplnjlojthcra, but pustules of the

lateral areas of C. gemma are arranged in 4-7

radiating rows (Pilsbry, 1892; Ferreira, 1983a),

whereas those of C. staphylophera are not

FIGS. 18-21. ( 'haetvpleura a pi ruin In (Say). 11.0 mm; Anclote Key,

valve VIII (all x 111); 21, dorsal girdle scales ( x 600).

Fieri. la. :■; m; FSBC 1 .",17li4: 18. valve I; 19, valve IV; 20.

in THE NA1TI1J/S

April 29, 1985

Vol. 99 (2-3)

aligned except at anterior margins. Likewise,

there are LO-15 longitudinal rows of pustules on

centra] areas of ( '. gemma (fide Ferreira, 1983a),

whereas C. staphylophera lias as many as 20

such rows. The tail valve of C. gemma illustrated

by Pilsbry (1892: pi. 13, fig. 74) also differs from

that of C. staphylophera, being ornamented with

many radial rows of numerous beads rather

than the essentially nonaligned pustules of the

new species.

Clim tujih/n-ii stiijihi/lD/ihirn is distinguished

from Calloplax janeirensis [3.\s,o = Chi I on smccr-

binna Reeve, 1847, formerly considered a

species of Chaetopleura, fide Ferreira (1979)],

the only other species of Chaetopleuridae in

Florida and the northern Caribbean, by posses-

sion in the latter of strong radial ribs (Fig. 16) or

rows of loosely coalesced pustules (Figs. 17,

22-24) instead of unaligned pustules on end

valves and lateral areas of intermediate valves.

However, the new species resembles C. janei-

rensis in the size and shape of pustules, in the

30

FIGS. 28-30. Major lateral radular teeth: 28.

Chaetopleura staphylophera n. sp. (> 450); 29.

Chaetopleura apiculata (x 4(iii); .'{0, "Calloplax"

janeirensis ( ■ 500).

TK^b,

JM*^

FIGS. ■i'l-Ti. 22-25, "Calloplax" janeirensis (Cray), L0.5

mm; Dry Tortugas, Florida. 1 m; FSBC I 31767: 22, valve I;

2:t, valve tV: 21. valve VIII (all x 12); 25, dorsal girdle

I • 300); 26, "C. "janeirensis, L5.5mm;Kej Vaca, 1 m;

i 31766; girdle ipicule < ■ 200); 27, "C " jam irensis,

ii \ aca, Florida, 1 m; FSBC I 31766; ventral

girdle scale i • 300).

pel 'lily surface of the interpustular tegmentum

of head and tail valves (Figs. 1, 3, 22, 24). and in

morphology of scales (Figs. 7, 8, 25, 26) and

scattered glassy spicules (Figs. 6. 27) of the dor-

sal surface of the girdle. Both species also

possess radulae with tricuspid major lateral

teeth, but cusps are much longer and more acute

on teeth of C. staphylophera than are those of ( '.

janeirensis (Fig. 30).

Ferreira' s statement (1983a: p. 220) that

Chaetopleura gemma "poses no diagnostic prob-

lems [as a species of Chaetopleura] given its very

different characteristics in shape, size and sculp-

ture [including "tubercular ridges" on lateral

areas]" is perplexing because that species, like

C. staphylophera, also strongly resembles

Calloplax janeirensis. Efforts to clarify the

generic affinities of these species prompted a

review of recent treatments of both genera.

Thiele (1909) erected Calloplax to contain

Cliihm junei rensis Gray, 1828. which occurs

from Brazil to south Florida. Assigned to Chae-

topleura Shuttleworth, 1853, by several authors

during the latter half of the nineteenth century,

( '. janeirensis was separated from that genus by

Thiele because the pustules of the head. tail, and

lateral areas of intermediate valves are much

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 41

larger than those of species of Chaetopleura and

are usually coalesced to form prominent ribs.

Calloplax was placed in Chaetopleuridae by

Thiele (1929) where it remained until recently.

No additional species were described until A. G.

Smith and Ferreira (1977) reassigned the ende-

mic Galapagos species Callistochiton duncanus

Dall, 1919, to Calloplax, thereby establishing

the presence of the genus in the eastern Pacific;

Smith and Ferreira concurrently reassigned

Calloplax to Callistoplacidae. Soon thereafter,

Ferriera (1978) transferred a Chilean species,

Callistochiton viviparus Plate, 1899, to

Calloplax, redescribed C. janeirensis and C.

duncanus, reviewed synonymies of all three and

retained Calloplax in Callistoplacidae. More

recently, Ferreira (1982) described a third east-

ern Pacific species, Calloplax hanselmani, from

Peru and the Galapagos Islands northward to

Mexico. In that paper, Ferreira expressed

uncertainty regarding the taxonomic position of

Calloplax and, after assessing similarities be-

tween Calloplax, Chaetopleura and Callistochi-

ton, concluded that Calloplax should be returned

to Chaetopleuridae.

Although Ferreira (1978, 1982) twice provided

diagnostic comments for Calloplax and most

recently (1983a) provided similar comments for

Chaetopleura, he did not define characters

separating species of the two genera. Difficulty

in identifying differences between the genera

has been complicated by unequal application of

diagnostic characters. Thus, Ferreira's (1982)

diagnosis of Calloplax mentions overall shape,

tegmental ornamentation, location and config-

uration of the mucro, and girdle ornamentation,

whereas his (1983a) diagnosis of Chaetopleura

includes comments on size, tegmental ornamen-

tation, insertion plates, slits of intermediate

valves, eaves, girdle ornamentation, gills, and

radular morphology. To allow more equitable

comparison of the two genera, information on

the above characters and on girdle bridges (see

Ferreira, 1983a) was compiled from species

descriptions as well as diagnoses in each of

Ferreira's three papers (Table 1).

Information in Table 1 reveals that although

some species of Chaetopleura have features

(e.g., small pustules on head and tail valves and

lateral areas of intermediate valves; girdle

hairs; bicuspid major lateral tooth) not found on

any species of Calloplax, all features except the

radial ribs of some species of Calloplax are fully

contained within the range of characters of

Chaetopleura. In fact, Calloplax hanselmani has

radial rows of unconnected pustules, not ribs, in

areas where ribs customarily occur on species

assigned to Calloplax. and even ribs of C. janei-

TABLE 1. Diagnostic Characters in Recent Reviews1 of Chaetopleura and Callopla

Character

( 'lini-tnpli'iirn

< 'alloplax

Size

Shape

Tegmentum

Insertion piates

Intermediate valves

Eaves

Mucro

(lirdle

( rirdle bridges

Gills

Radula

Small to large (8-60 mm length).

Ovate (length/width ratio 1.4-1.8:1).

Larger pustules in quincunx or radial rows in

end valves and lateral areas of intermediate

valves; smaller pustules in longitudinal

rows or coalesced in riblets in central

areas.

With "rather sharp" teeth.

Uni-slit.

Solid.

Posterior, central or slightly anterior

concave or convex postmucro, with

without additional false mucro.

With minute, simple, oval to spiculoil

interspersed with glassy, hyaline s]

some species with horny hairs.

With or without spicular elements.

Holobranchial, abanal.

Median tooth wide, subquadrangular; major

lateral teeth tricuspid or bicuspid.

with

1 scales,

licules;

Small to medium (13-21 mm length).

Elongate (length/width ratio ca. 2:1).

Strong radial ribs or rows of pustules in end

valves and lateral areas of intermediate

valves; longitudinal, often granulose

riblets in central areas.

With "CallistockitonAike" to "relatively

sharp" teeth.

Uni-slit.

Solid.

Centra] or slightly anterior, with convex

postmucro.

With spicules (not hairs) interspersed amidst

small, ovoid, closely parked, coarsely

striated scales.

With or without spicular elements.

| Not defined].

Median tooth wide, subquadrangular; major

lateral teeth tricuspid.

'From Ferreira (1978, 1982, 1983a)

2Ranges based on largest reported sizes of various species.

42 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

rensis occur as rows of loosely connected pus-

tules in some specimens from Florida (Figs. 22-

24) and Rio de Janeiro (Fig. 17), the type-locality

of the type-species of Calloplax. This seems to

eliminate the value of radial ribs as a generic

character and requires the conclusion that

( 'ullopliu: is a junior synonj m of ( 'haetopleura.

A brief review based upon morphological in-

formation available in published literature

(Pilsbry, 1892; Thiele, 1893; Plate, 1899; Righi,

1967, 1970; Bullock, 1972; Ferreira, 1978, 1982,

1983a) suggests that most of the 22 New World

species of Chaetopleuridae are separable into

two groups as defined by Pilsbry (1892: p. 28):

"(1) typical forms, rather large, and having very

delicate sculpture; and (2) group of C. gemma,

having the lateral areas strongly raised and

coarsely sculptured." These groups approximate

those previously allotted to Chaetopleura and

Calloplax, but some "intermediate" species do

not conform fully to either group (Table 2).

The first group is comprised of species with

bicuspid lateral radular teeth, corneous girdle

hairs in addition to scales and glassy spicules,

and small tegmental pustules widely scattered

or separated in rows. This group includes Chae-

topleura angulata (Spengler, 1797), C. apinilatu

(Say, 1834), C. asperrima (Gould, 1852), C. hen-

nahi (Gray, 1828), C. iquiquensis (Plate, 1899)

and C. peruviana (Lamarck, 1819). Radulae of

C. benaventei Plate, 1899, and C. fernandensis

Plate, 1899, have not been described, but these

species closely resemble C. peruviana and C.

i/ptiiptrttsis, respectively, in other characters

(see Ferreira, 1983a: p. 221), so they also may

belong to this group. Ferreira (1983a) implied

that C. unilineata Leloup, 1954, lacks girdle

hairs, but a photograph (his fig. 28) seems to

show scattered hairs on the girdle of that

species; if present, they would place C. unili-

neata in this group as well. I am unable to ascer-

tain whether C. isabellei (d'Orbigny, 1841) or C.

TABLE 2. Groupings of New World Chaetopleura species, based upon features of the girdle, radula and tegmentum.

Vol. 99(2-3)

April 29, 1985

THE NAUTILI'S 43

spinulosa (Gray, 1828) have girdle hairs; if so,

those species also belong here. The type-speeies

of Chaetopleura is Chiton peruvianus Lamarck

[subsequent designation, Dall (1879)], so species

in this group would best typify Chaetopleura s.s.

Although central areas of its intermediate

valves bear rows of tiny, coalesced pustules,

Chaetopleura cumin Righi, 1970, entirely lacks

tegmental pustules on head and tail valves and

on lateral areas of intermediate valves. In this

regard, C. carrua resembles C. angulata. a

species in which tegmental pustules may be

nearly obsolete. Its bicuspid radula appears to

ally C. carrua with the above group.

Chaetopleura scabricula (Sowerby, 1832) also

resembles species in the above group by having

small tegmental pustules and distinct girdle

hairs but differs by having tricuspid lateral

teeth. Chaetopleura, lanuginosa (Dall, 1879)

likewise resembles species in the first group by

having small, scattered tubercles but lacks

girdle hairs and has tricuspid lateral teeth.

Chaetopleura roddae Ferreira, 1983, and C.

shyana Ferreira, 1983, each lack girdle hairs,

have tricuspid lateral teeth, and have densely

packed unaligned tegmental pustules on head

and tail valves and lateral areas of intermediate

valves. Although relatively smaller than pus-

tules on species in the following group, densities

and arrangements of these pustules are sug-

gestive of some species in that group.

The next group includes C. janeirensis, the

type-species of Calloplax. In addition, Chaeto-

pleura gemma Dall, 1879, C staphylophera, n.

sp., and C. hanselmani (Ferreira, 1982) all lack

girdle hairs, have tricuspid lateral teeth, and

have large tegmental pustules on the head and

tail valves and lateral areas of intermediate

valves. Pustules may be unaligned (C. staphy-

lophera) or arranged in rows (C. gemma, C.

hanselmani, C. janeirensis) which sometimes in

C. janeirensis coalesce into radial ribs; two or

more such ribs may occur on lateral areas of in-

termediate valves. Girdle scales and spicules of

species in this group resemble those of other

species in the group moreso than they resemble

those of any other Chaetopleura species (for ex-

ample, see C. apiculata. Fig. 21).

Chaetopleura duncana (Dall, 1919) and C.

ririparn (Plate, 1899) pose additional problems

in placement. Each lacks girdle hairs, has tricus-

pid lateral teeth, has strong radial ribs on head

and tail valves, and has only two such ribs on

lateral areas of intermediate valves. The low,

conical or dome-like girdle scales of these

species as illustrated by Ferreira (1978) are dis-

similar from any other species of Chaeto-

pleuridae.

Additionally, there are at least three species

of Chaetopleura in South Africa, possibly two in

west Africa, one in east Africa, and one in east

Asia (Ferreira, 1983a, b). Insufficient informa-

tion is available to determine where most of

these fit in the above arrangement.

Acknowledgments

Hugh J. Porter, University of North Carolina

Marine Science Institute, Morehead City, pro-

vided his previously reported specimen for

study. John Reed and Dr. Robert A vent allowed

study of material collected during their study of

the deep-water Oculina reef community, spon-

sored by the Harbor Branch Foundation, off

central eastern Florida. Johnnie Johnson,

Brevard Museum, Inc., provided specimens

from the calico scallop grounds near Cape

Canaveral. Jack N. Worsfold, Freeport, Grand

Bahama, provided the single valves from that

area. Lana Tester, formerly FDNR Bureau of

Marine Research, produced the SEM photo-

micrographs, and Sally D. Kaicher provided

additional darkroom assistance. Dr. James F.

Quinn, Jr., FDNR, provided guidance in Greek

grammar. All are gratefully thanked.

LITERATURE CITED

Avent. R. M., M. E. King and R. H. Gore. 1977. Trophic and

faunal studies of shelf-edge prominences off the central

eastern Florida coast. Int. Revue ges. HydrobioL 62:

18.5-208.

Bullock, R. C. 1972. On the taxonomy of ( 'haetopleurafulva

(Wood, 1815)(Mollusca: Polyplacophora). Occ. Pap. Moll,

Mus. Comp. Zool, Harvard Univ. 3(42):177-191.

Burghardt. G. and L. K. Bunrhardt. Hni9. A collector's

guide to west coast chitons. Spec. Publ. No. 4, San

Francisco Aquarium Soc, Inc. 45 pp., 4 pis.

Clark, R. N. 1982. Chitons of the north-east Pacific. Of Sea

and Shore 12(3): 147-153.

Dall, W. H. 1879. Report on the limpets and chitons of the

Alaskan and Arctic regions, with descriptions of genera

and species believed to lie new. Proc. U.S. Natl Mus.

1:281-344, 5 pis.

1919. Descriptions of new species of chitons

from the Pacific coast of America. Proc. U.S. Natl. Mus.

55(2283):449-516.

44 THE NAUTILI'S

April 29, 1985

Vol. 99(2-3)

Ferreira, A. J. L978. The genus Calloplaj- Thiele, 1909

(Mollusca: Polyplacophora) in the Americas. Bull. So.

Calif. Acad. Sci. 77(2):56-64.

1979. The genus Callistochiton Dall. 1879

(Mollusca: Polyplacophora) in the eastern Pacific, with the

description of a new species. Veliger 21(4):444-466, 3 pis.

1982. A new species of Calloplaj (Mollusca:

Polyplacophora) in the eastern Pacific. Veliger 24(4):

321-324, 1 pi.

1983a. The genus Chaetopleura Shuttleworth,

1853 (Mollusca: Polyplacophora) in the warm-temperate

and tropical eastern Pacific, southern California to Peru,

with the description of two new species. Veliger 25(3):

203-224, 4 pis.

1983b. Researches on the coast of Somalia. The

Chiton fauna (Mollusca Polyplacophora). Hal. J. Zoo/.,

n.s., Suppl. 18, 9:249-297.

Gray, J. E. 1828. Spicilegia Zoological or Original Figures

and Short Systematic Descriptions of New and Unfigured

Animals. Part 1: 8 pp, 6 pis. British Museum.

Joyce, E. A., Jr. and J. Williams. 1969. Rationale and

pertinent data. Mem. Hourglass Cruises 1(1): 1—50.

Kaas, P. 1972. Polyplacophora of the Caribbean region.

Stud. Fauna Curasao and other Caribb. Ids. 41(137):

1-162, pis. 1-9.

Kaas, P. and R. A. Van Belle. 1980. Catalogue of Living

Chitons. W. Backhuys, Rotterdam. 144 pp.

Kennedy, F. S., Jr., J. J. Crane, R. A. Schlieder and D. G.

Barber. 1977. Studies of the rock shrimp, Sicyonia

brevirostris, a new fishery resource on Florida's Atlantic

shelf. Flo. Mar. Res. Publ. No. 27. 69 pp.

Lyons, W. G. 1982. Comments on chitons (Mollusca: Poly-

placophora) of the Bahama Islands. Bull. Am. Malaeol.

Union 1982: 38, 39. Abstract.

Orbigny, A. d'. 1841. Voyage dans VAmerique Meridionale

(1826-1833), 5(3):482-489.

Pilsbry, H. A. 1892. Polyplacophora, (Chitons). Lepido-

pleuridae, Ischnochitonidae, Chitonidae, Mopaliidae.

Manual ofConchology 14:1-350, pis. 1-68.

Plate, L. H. 1899. Die anatomie und phylogenie der

chitonen. Fauna Chilensis. Zool, Jahrb. 5(11):15-216,

pis. 2-11.

Porter, H. C. 1974. The North Carolina marine and

estnarine Mollusca; an atlas of occurrence. Univ. North

Carolina Inst. Mar. Sci., vi + 351 pp.

Putnam, B. F. 1980. Taxonomic identification key to the

described species of polyplacophoran mollusks of the west

coast of North America (north of Mexico). Pacific Gas and

Electric Co., Dept. of Engineering Research, Rpt. 411-

79.342. 164 pp.

Reed, J. K, R. H. Gore, L. E. Scottoand K. A. Wilson. 1982.

Community composition, structure, areal and trophic

relationships of decapods associated with shallow- and

deep-water Oculina varicosa reefs: Studies on Decapod

Crustacea from the Indian River region of Florida, XXIV.

Bull, Mar. Sci. 32(3):761-786.

Reeve, L. A. 1847. Monograph of the genus Chitnn. ' 'onch.

lam. 4, 28 pis.

Righi, G. 1967. Sobre Polyplacophora do litoral Brasileiro.

Pap. Avul. Zool. Sao Paulo, 20(9):85-97.

1970. Mollusques polyplacophores. Resultats

scientifiques des campagnes de la "Calypso" au large des

cotes Atlantiques de VAmerique du Sud (1961-1962)

9(19):107-114.

Say, T. 1834. American rmichology. or descriptions of the

shells of North America. Part 7. Appendix.

Shuttleworth, R. 1853. Uber den Bau der Chitoniden, mit

Aufzahlung der die Antillen und die Canarischen Inseln

bewohnenden Arten. Mitth. Naturf. Ges. Bern (286-291):

169-207.

1856. Description de nouvelles especes. Premiere

decade: especes nouvelles pour la faune des Antilles.

Jour, de Conchyl. 5:168-175.

Smith, A. G. and A. J. Ferreira. 1977. Chiton fauna of the

Galapagos Islands. Veliger 20(2):82-97. 4 pis.

Spengler, L. 1797. Udforlig Beskrivelse ovet det manges-

kallede Konkylie-Slaegt af Linnaeus kaldet Chiton met

endeel nye Arten og Varieter. SkrivL Naturkist. Selsk.

4(0:62-1 03.

Thiele, J. 1893. Polyplacophora, Lepidoglossa, Schuppen-

zilngler. Pp. 353-401, pis. 30-32 in F. H. Troschel. Das

Gebiss der Schnecken zur Begriindung einer naturliehen

Classification, 2.

1909. Revision des Systems der Chitonen. Teil

I. Chun's Zoologiea 22(56):l-70, figs. A-E, pis. 1-6.

1929. Handbuch der systematischen Weichtier-

kunde. Loricata. 1(1): 1-22. Jena.

Conchologists of America

The annual meeting of the Conchologists of

America will be held in Philadelphia June 22-26,

1985, where it will be hosted by the Philadelphia

Shell Club at the Academy of Natural Sciences

of Philadelphia and a nearby hotel. For reserva-

tion forms write: Frank Roach, 1028 Belvoir

Rd., Norristown, PA 19401.

1985 AMU Meeting

The American Malacological Union will hold

its annual meeting on the campus of the Univer-

sity of Rhode Island on July 29-August 3, 1985.

For further information please contact Dr. M.

R. Carriker, College of Marine Studies, Univer-

sity of Delaware, Lewes, DE 19958.

Vol. 99 (2-3)

April 29, 1985

THE NAUTILUS 45

ARENE FLEXISPINA. A NEW SPECIES (GASTROPODA: LIOTIIDAE)

FROM OFF EASTERN BRAZIL

Jose Henrique N. Leal1 and Arnaldo C. dos Santos Coelho

Setor de Malacologia2 - Museu National

20.942 - Rio de Janeiro, RJ - Brasil

Seven species of the genus Arene H. & A.

Adams, 1854 are already known from the Brazil-

ian coast: Arene tricarinata (Stearns, 1872), A.

briareus (Dall, 1881), A. variabilis (Dall, 1889),

A. bairdii (Dall, 1889), A. brasiliana (Dall,

1927), A. riisei Rehder, 1943 (Abbott, 1974;

Rios, 1975) and A. notialis Marini, 1975 (Marini,

1975). The present description is based on speci-

mens obtained through bottom sampling (van

Veen and Petersen grabs) between 54 and 82

meter depth during the GEOMAR X cruise

undertaken by the Brazilian Navy research

vessel "N.Oc. Almirante Camara" along the

eastern coast of Brazil, in the period of 01-11

June 1978. Sampled substrate in the three sta-

tions where the species was found consisted of

fragments of calcareous algae and calcareous

gravel. Although soft parts are not preserved,

thus making difficult a more accurate taxonomic

characterization, shell features are markedly

distinct.

Arene flexispina new species

(Figs. 1-3)

Description: Shell small, solid, trochoid in

shape, reddish brown, with spiral rows and

spines of lighter color. Ratio height/width of the

shell higher in adults than in younger speci-

mens. Whorls 5V2, the first IV2 comprising the

protoconch, white and smooth, lower than the

subsequent whorl. Teleoconch whorls with 2

larger peripheral spiral rows of 10 or 11 large,

fluted spines spirally raised and imbricated.

Narrower row 1-2 subsutural, one intermediate

(between the 2 larger) and one immediately

above the subsequent whorl, with numerous im-

bricated scale-like spines, smaller than those in

the 2 larger rows. Finely incised axial lines on

entire shell microscopic and crowded. Suture

'Present address: B.L.R., Rosenstiel School of Marine and

Atmospheric Science, 4600 Rickenbacker Causeway, Miami,

FL 33149

Contribution no. 46

channeled, clearly defined. Body whorl rounded,

with wider spiral cords; spines in the 2 larger

cords triangular, bent outwards and sharply

pointed in apical view; spines number the same

as in the spire. Base with 4 or 5 well-separated

beaded spiral cords; beads almost imperceptible

in worn specimens. Cord bordering the umbili-

cus the same size or only slightly larger than the

other basal cords (younger specimens). Um-

bilicus wide, deep and twisted, with fine axial

lines internally. One or two cords entering the

umbilicus in younger shells, absent in mature

specimens. Aperture whitish, oblique. Outer lip

thin, with crenulations corresponding to the ex-

ternal spiral ornamentation. Operculum round,

multispiral, with small radial lines giving beaded

aspect to its calcareous external surface.

Attachment side horny and convex.

Material examined: GEOMAR X station 048,

40 km off Ponta de Corumbau, Bahia, Brazil

(16°56'30"S, 38°39'30"W), 80 m depth, "N.Oc.

Almirante Camara" col. 09 June 1978, Holotype,

Museu National, Rio de Janeiro, Brazil (Col.Mol.

MN 5352), height 6.4 mm, width 6.7 mm; Para-

type 1, United States National Museum, Wash-

ington, D.C. (USNM 820786), height 5.4 mm,

width 6.2 mm; Paratype 2 (Col.Mol.MN 5353),

height 4.7 mm, width 5.4 mm; Paratype 3,

Museu Oceanografico, Fundacao Universidade

do Rio Grande, Rio Grande, Brazil (MORG

22807), height 3.5 mm, width 4.5 mm; Paratype

4 (USNM 820786A), height 3.4 mm, width 4.3

mm; Paratype 5 (MORG 22808), height 3.2 mm,

width 4.3 mm; GEOMAR X station 038, 170 km

off Conceicao da Barra, Espirito Santo, Brazil

(18°49'00"S, 37°52'00"W), 54 m depth, "N.Oc.

Almirante Camara" col. 07 June 1978, Paratype

6 (MORG 22619), height 2.0 mm, width 3.0 mm;

GEOMAR X station 047, 120 km off Abrolhos

Reef, Bahia, Brazil (17°44'00"S, 37°21'00"W), 54

m depth, "N.Oc. Almirante Camara" col. 08

June 1978, Paratype 7 (Col.Mol.MN 5354),

height 1.4 mm, width 2.4 mm.

46 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

FIGS. 1-3. Arene flexispina n. sp. 1 and 2, Apertural and

ventral views of the holotype, Col.Mol.MN 5352, 40 km off

de Corumbau, Bahia State, Brazil. Scale bar=2 mm.

.'!. Apertural view with operculum of the paratype >'<. MORG

■ off ( 'onceicao da Barra, Espirito Santo State,

Brazil. Scale bar= 1 mm.

Type locality: Brazil, Bahia State, 40 km off

Ponta do Corumbau, (16°56'30"S, 38°39'30"W),

80 m depth, calcareous algae bottom (Fig. 4).

Etymology: The specific name stands for the

large outwardly bent spines in the spiral cords

of the spire and body whorl.

Remarks: The species seems to belong in the

subgenus Arene s.s. which is, as stated by Keen

(1971:345), characterized by a sculpture of

coarsely beaded spiral cording on the body

whorl and base, the periphery rounded or

stellate. Although A. flexispina n. sp. possesses

some of the characters of the subgenus Mareval-

vata Olsson & Harbison, 1953, such as general

outline, spiral cords in the umbilicus wanting in

mature specimens and outer lip not thickened, it

doesn't exhibit the diagnostic flattened base

with radial lines extended from the umbilicus

and a nacreous inner layer (Olsson & Harbison,

1953:348; Keen, 1971:346). Further investiga-

tions or a revision work on the western Atlantic

species of Arene seems to be necessary to con-

firm the positioning of A. flexispina at

subgeneric level.

17

18

BAHIA

STATE

BRAZIL

048

ABROLHOS

REEF

COMPLEX

047

038

FIG. 4. Location of the three GE( >MAK X stations in which

Arene flexispina n. sp. was found (solid triangles). The type

lecality is represented by station (MS. Inset shows position of

the area in southern Atlantic Ocean.

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 47

It was observed from the shell measures of the

8 examined specimens of A. Jlexispina that the

ratio height/width increases as the shell grows,

suggesting a pattern of allometrie growth (Fig.

5), probably a consequence of a gradual altera-

tion in the angle of coiling in the species.

A rene Jlexispina appears to be related to A.

briareus from the Caribbean and tropical west-

ern Atlantic, according to the original descrip-

tion (Dall, 1881:52), and later illustration by the

same author (Dall, 1889: pi. 24, figs. 5, 5a), and

by comparison of specimens (Col.Mol.MN 5390;

Morg 14.969), mainly by its elevated spire and

spinose ornamentation. A. jlexispina differs,

however, by its darker color, two obviously

larger cords on body whorl, which are all about

the same size or only a little larger than the re-

maining in briareus; ornamentation of the spiral

cords consisting in about 11 large fluted spines,

instead of about 40 small spines in briareus; a

well differentiated ridge or cord around the um-

bilicus and a nodulose spiral ridge inside it in

briareus, not present in Jlexispina; outer lip

thicker in briareus.

Arene notialis from off southeastern Brazil

differs by its whitish color, lower spire, about 21

width (mm)

FIG. 5. Allometrie shell growth in Arene jlexispina n. sp.;

sketches illustrate the shape of shells at three points on the

curve: a) Paratype 7, Col.Mol.MN 5354, height 1.4 mm,

width 2.4mm; b) Paratype 3. MORG 22807, height 3.5 mm,

width 4.5 mm; c) Holotype. Col.Mol.MN 5352, height 6.4

mm, width 6.7 mm. Scale bars= 1 mm.

nodules (not spines) on spiral cords in the body

whorl, 8 joined strongly beaded basal spiral

cords instead of 5 separated cords in Jlexispina;

umbilicus smaller and straight, bordered by a

larger basal cord and outer lip thicker in

notialis, according to Marini (1975) and material

examined of A. notialis from off Guarapari,

Espirito Santo, Brazil, "N.Oc. Almirante

Saldanha" col. September 1968, 80 m depth,

Col.Mol.MN 4862, two specimens.

Acknowledgments

We are indebted to Dr. Donald R. Moore from

the Rosenstiel School of Marine and Atmos-

pheric Science, Miami, for the critical review of

the manuscript, to the staff at Departamento de

Hidrografia e Navegacao, Ministerio da

Marinha, Brazil, for providing the adequate con-

ditions to the obtention of the material exa-

mined, during the GEOMAR X cruise, to Prof.

Eliezer de C. Rios, Museu Oceanografico, Rio

Grande, Brazil, who made available part of the

studied material and to Mr. Raul Garcia, Rio de

Janeiro, Brazil, for the drawings of Arene Jlex-

ispina.

LITERATURE CITED

Abbott, R. T. 1974. American Seashells (2nd Edition). Van

Nostrand-Reinhold, New York, 663 pp.

Dall, W. H. 1881. Reports on the Results of Dredging, under

the Supervision of Alexander Agassiz, in the Gulf of

Mexico, and in the Caribbean Sea, 1877-79, by the United

States Coast Survey Steamer "Blake", . . . XV. Prelimi-

nary Report on the Mollusca. Bull. Mus. Comp. Zooi.

Harvard Univ., Cambridge 12(6):171-318, pis. 1-9.

1889. Reports on the Results of Dredging, under

the Supervision of Alexander Agassiz, in the Gulf of

Mexico (1877-78) and in the Caribbean Sea (1879-80), by

the U.S. Coast Survey Steamer "Blake", . . . XXIX. -

Report on the Mollusca. Part II. - Gastropoda and Scapho-

poda. Bull. Mus. Comp. Zool. Harvard Univ., Cambridge

18:1-492. 31 pis.

Keen, A. M. 1971. Sea Shells of Tropical West America.

Stanford University Press, Stanford, 1064 pp.

Marini, A. C. 1975. Sobre duas especies novas de micro-

moluscos (Trochacea: Turbinidae; Liotiidae) da costa

brasileira. Pap. Ainil. Zool. St. Paulo 29(5):31-34, 2 pis.

Olsson, A. A. and A. Harbison. 1953. Pliocene Mollusca of

Southern Florida, with special reference to those from

North Saint Petersburg with special chapters on Turridae

by Williams G. Fargo and Vitrinellidae and Fresh-water

Mollusks by Henry A. Pilsbry. Acad. Nat. Sci. Philad..

Monog. 8:1-457, 65 pis.

Rios, E. C. 1975. Brazilian Marine Mollusks Iconography:

Fundacao Universidade do Rio Grande, Rio Grande,

331 pp., 91 pis.

48 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

AN EXCEPTIONAL STREAM POPULATION OF THE BANDED

APPLE SNAIL, VIVIPARUS GEORGIANUS, IN MICHIGAN

Gary L. Pace and Ernest J. Szuch

Department of Biology

University of Michigan-Flint

Flint, MI 48502-2186

ABSTRACT

SCUBA and a Surber sampler were used to study a stream population of

Viviparus georgianus (Lea). This locality, at the mouth ofRunyan Creek where it

flows into Hoisington Lake in Livingston County, Michigan, is only the fourth

known locality for any species of Viviparus in that state. Densities were high (up

to 86^/m2) and varied significantly with gender (female > male), station type

(reach > meander), and station position (upstream > downstream). Mean weight

varied in the same ways with respect to gender and station type, but conversely for

station position (whether downstream or upstream). The only effective interaction

between factors was that between gender and station position: females decreased

in size upstream faster than males. Weight -frequency data combined for all sta-

tions supported the independent measures of sex ratio (females > males) and sex-

ual dimorphism in size.

The main purpose of this paper is to draw at-

tention to the fourth known population of Vivi-

parus georgianus from Michigan. Voucher

specimens have been deposited in the University

of Michigan Museum of Zoology. The population

thrives in Runyan Creek where it flows into

Hoisington Lake in northern Livingston Coun-

ty. Here the stream is narrow (less than 6 m),

steep-sided, and varies in depth from 85 to 156

cm as it meanders through an extensive marsh.

The substrate is largely organic detritus con-

tributed from marsh and stream plants (e.g.,

Spartina pectinata, Scirpus lineatus, Typha

latifolia, Nuphar variegatum, Lythrum deco-

don). Our interest in this population derives

from the rarity of this species in Michigan and

from the very high densities found in a locality

which must be very near this species' northern

limits of distribution.

Since its discovery by two of our students,

Donald House and Philip Davis, several papers

have been published on the physiology of these

snails (Fitch, 1975, 1976; Buckingham & Freed,

1976; Davis & Fenner, 1977; Studier & Pace,

1978). Ecological studies on this and related

species include those of Van Cleave & Lederer

(1932), Stanczykowska, et al. (1971, 1972), Burla

(1972), Samochwalenko & Stanczykowska

(1972), Young (1975), de Bernardi, et al. (1976),

Brown (1978), Plinski, et al. (1978), Vail (1978),

Imlay, et al. (1981), Jokinen (1982) and Thomp-

son (1985). The main studies of the systematics

and distribution of North American viviparids

were those of Clench (1962) and Clench & Fuller

(1965).

Materials and Methods

Many species of temperate, freshwater mol-

lusks including Viviparus, move to deeper

water, burrow into the substrate, and become

less active during the Fall and Winter (Burla,

1972; Young, 1975). Therefore, when dredging

and SCUBA assisted visual search methods

have been used to collect these mollusks, this

Fall migration has resulted in the under-

sampling of the population (Burla, 1972; Young,

1975; de Bernardi, et al. 1976). In narrow, steep-

sided channels, however, this Fall migratory

behavior serves to concentrate the population

into the bottom detritus. Under these circum-

stances, the Fall may very well be the best

single time of the year to study certain popula-

tion characteristics.

During the last week of September, SCUBA,

was used to collect three Surber samples (0.093

m2 x 7.62 cm) at each of 12 stations selected at

the centers of consecutive stream meanders and

reaches. Since samples were collected from

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 49

meanders and reaches whose radii and lengths

varied considerably, stream channel distances

between stations were not equal. The samples

were taken from the deepest part of the stream

cross-section with minor adjustments where

water-lily rhizomes prevented forcing the

sampler fully into the substrate. Everything

within the frame was then scooped into the

Surber net, brought to the surface, and trans-

ferred to labeled plastic containers for transport

to the laboratory. In the lab, snails were sorted

from the detritus, sexed, and then weighed on a

top-loading balance to 0.01 g. Wet (live) body

weight was used since Davis and Fenner (1977)

showed its direct relationship to dry weight for

these snails.

Results'

Total densities ranged from 151/m2 to a max-

imum of 864/m2. The average population den-

sities were significantly higher in the reaches

(608/m2) than in the meanders (534/m2). Closer

examination showed that the average density of

the males was the same in these two types of

habitats (243:228/m2). The difference, therefore,

was in the number of females (365:306/m2).

While females outnumbered males in all stations

combined (female/male = 1.42), the difference

was greater in reaches (female/male = 1.50) than

in meanders (female/male = 1.34). A comparison

was also made between the six most down-

stream stations and the six most upstream sta-

tions. An average density of 462/m2 was found

for the downstream populations, while that of

the upstream group was 680/m2. Thus, the

upstream populations were significantly denser

than the downstream populations.

Live body- weight averages computed for each

station (sexes combined) ranged from 0.75-1.97

g. The average size of the reach snails (1.57 g)

was larger than that of the meander snails (1.35

g). Also, the average size of the females (1.90 g)

was nearly twice that of the males (1.01 g). Fur-

thermore, while the average size of both sexes

decreased upstream, females decreased faster

than males (Fig. 1).

Frequency distributions of weight classes for

each sex were constructed for each station

1.0

'Readers wishing tabular data on density and mean weight

distributions among the stations along with their statistical

analyses may write the authors for copies.

4-5 6-7 8-9 10-11 12-13 14-15

S tation No

(Upstream -*)

FIG. 1. Rates of change in male and female mean weights

with stream position. Each point represents the mean of 20

meander and 20 reach snails selected randomly. The vertical

bars represent +/- 2 Standard Errors. The curves are

regression lines based on the mean weights for males and

females separately. Females: Intercept = 2.378, Slope =

-0.162. Males: Intercept = 1.308, Slope = -0.088.

separately and for all stations combined. All

curves for both sexes showed bimodal distribu-

tions of weight classes. Because the results were

comparable for all stations, curves are provided

only for the combined data (Fig. 2). We assume

that size is at least roughly correlated with age

(de Bernardi, et al., 1976) and we will refer to

the obvious groupings in Fig. 2 as cohorts.

The younger cohort for each sex had a mode at

about 0.5 g, and ranged from 0.2-0.8 g for males

and from 0.2-1.0 g for females. Females were

slightly larger than males in this cohort, and

outnumbered males 616 to 518. In the older

cohort, 358 males weighed from 0.9-3.5 g, while

606 females weighed from 1.1-8.9 g. These

curves, as well as the data already discussed in-

dicate that the average adult female is nearly

twice as large as the average adult male. Note

also that there is no significant difference be-

tween the number of females in the two cohorts

(616 & 606) and that in each, females out-

numbered males (518 & 358). Finally, note that

males were more numerous in the younger

cohort than in the older one.

Discussion

As the papers by Clench (1962) and Clench &

Fuller (1965) have documented, Viviparus

i/mri/nunis (Lea) has apparently only invaded

50 THE NAUTILUS

April 29, 1985

Vol. 99 (2-3)

— Mole

-_ Femole

it ft «

« \ A A

r*V--

10 20 30 40 50 60 70

Wl |gm)

FIG. 2. Weight-frequency curves for all snails, sexes separate.

the northern states during the last century. Fur-

thermore, Clench pointed out that only three

localities are known from Michigan, and that

these have been presented to the University of

Michigan Museum of Zoology since the publica-

tion of Winslow's (1926) checklist of Michigan

mollusks: UMMZ 166266 and 177214: Coguac

Lake, 2 mi S.W. Battle Creek, Calhoun Co.,

Leslie Hubricht. Oct. 6, 1946; UMMZ 167226:

Park N. of Owasso, Shiawassee Co., H. van der

Schalie & Aurele LaRocque. July 10, 1947;

UMMZ 173445: S. side Silver Lake, 15 mi N.E.

Grand Rapids, Kent Co., C. D. Nelson. (No date

recorded).

While it is possible that any specific locality

may have long been populated and yet over-

looked by collectors, it must be admitted that

\'irij„,rus is rare in Michigan. It is well-known

that Michigan's molluscan fauna has long been

among the best known in the world. Neverthe-

less, the above four lots of V. georgianus are in

contrast to hundreds of lots of Michigan

Campeloma integrum and C. decisum which fill 5

and 7 UMMZ cabinet drawers, respectively.

Not only is this one of the few Michigan

localities for Viviparus, but it appears that

among those so far reported, this locality most

closely approaches this species' optimal habitat.

This is supported by the fact that the population

reached a maximum density of 864/mi and a

maximum standing crop biomass (density x

average live weight) of 1163 g/m2. These data

are higher than any yet reported for this species

(Van Cleave & Lederer, 1932; Vail, 1978;

Browne, 1978). Furthermore, these data exceed

those for any freshwater snails (Hyman, 1967)

and may prove to represent one of the largest

standing crop biomass records among fresh-

water gastropods. These results are unexpected

for a locality so near the northern limits of a

species' range. The timing and method of collec-

tion must certainly have contributed to these

high numbers (see Materials and Methods). The

substrate in this habitat is very rich in organic

detritus derived from the breakdown of the

plants of the extensive marsh through which

Runyan Creek slowly meanders. Earlier reports

of a fine detritus habitat preference (Harman,

1972), and of combined detritus (Fretter &

Graham, 1978) and filter (Cook, 1949) feeding

methods by Viviparus species, provide some ex-

planation for the optimal nature of this habitat.

It certainly seems better suited to this species

than its usually reported habitat "on the bottom

Vol. 99 (2-3)

April 29, 1985

THE NAUTILUS 51

of mesotrophic or eutrophic lakes and ponds"

(Browne, 1978). Indeed, at the mouth of Runyan

Creek into Hoisington Lake, the density of these

snails drops to less than one snail per square

meter. The fact that these snails thrive in this

detritus-rich habitat so near to their northern

limits of distribution may indicate that food

availability outweighs temperature or length of

growing season in determining their optimal

habitat.

Both sexual size dimorphism and disparate

sex ratios have previously been recorded for

northern populations of this (Van Cleave &

Lederer, 1932; Browne, 1978) and other species

of viviparids (Annandale & Sewell, 1921; van

der Schalie, 1965; de Bernaardi, et aL, 1976;

Vail, 1978). In Vail's (1978) Florida populations

of Viviparus georgianus, however, sexual size

dimorphism did not occur, and differences in sex

ratios were not noted. Thus there seems to be

both local and geographical variation in these

sexual attributes. In our studies, variation in sex

ratio could not be shown to be dependent on any

of the following variables: station type (meander

vs reach), station position (upstream vs down-

stream), water depth, water temperature, total

density, or total biomass. Our large sample

sizes, however, reduce the possibility that the

variation is the result of sampling error. That

these sexual differences are due to higher

female growth rates and longer female longe-

vity is suggested by our size-frequency data

(Fig. 2) which support the findings of others

(Van Cleave & Lederer, 1932; Browne, 1978).

Because we made our collections in late

September, our cohorts represent snails that

had survived one growing season (about 4

months) and those which had survived at least

two growing seasons and one winter (16-19

months). Some differential mortality (males >

females) and differential growth (females >

males) was evident by the end of the first grow-

ing season and increased substantially by the

end of the second. That these differences are not

due to differential numbers and size at birth is

supported on both factual and theoretical

grounds. Van Cleave and Lederer (1932) found

that the two sexes were present in equal

numbers at birth. Fisher showed long ago that

this is to be expected if there is no sexual dif-

ference in energy costs (i.e., no difference in

size) of the progeny to the parent (Pianka,

1974). Brown (1978), on bioenergetic and

anatomical grounds suggested that "selection

probably drives females toward a larger size

than males as a consequence of the cost of

viviparity." Furthermore, Browne pointed out

that males have two options in dividing their

energy resources. Evidently, some males devote

much of the first year in feeding and survival,

with most reproductive effort delayed until the

second growing season. Other males might

spend most of their time and energy actively

seeking females while spending relatively less

time feeding. While the latter were characteris-

tic of Browne's populations and would generally

be expected to leave more progeny, variation in

such strategies could account for some of the

variation in the distribution of sexual differ-

ences in size and number.

The fact that these snails are larger and more

numerous in reaches than in meanders seems

more easily testable. Higher currents in the

meanders may reasonably be expected to re-

move both young snails and detritus and deposit

them in the reaches. Even if the current rarely

displaces snails, the cumulative effect of erosion

and deposition on habitat enrichment in the

reaches could account for the differences in snail

density and biomass. Analysis of the variation of

the current velocity and sediment load between

habitat types and between seasons would be

very helpful in answering these questions.

It is perplexing that density and biomass in-

crease upstream while mean weights decrease

(see Results). Since biomass increases upstream

we might inquire whether the carrying capacity

{e.g., as determined by food availability) in-

creases upstream, or whether the upstream pop-

ulations are more efficient in filling their niche.

The first seems a more testable question.

Because upstream populations are denser but

individuals are smaller, we may ask whether or

not these snails are stunted as a result of

crowding {i.e., intraspecific competition). Also,

the larger size but lower density of the down-

stream snails may indicate that while some ex-

trinsic factor controls numbers, surviving snails

have ecological room for growth (i.e., crowding

reduced). Higher predation pressure on small

downstream snails could account for such popu-

lation characteristics. The seasonally dense

52 THE NAUTILI'S

April 29, 1985

Vol. 99(2-3)

populations of ducks and geese on Hoisington

Lake and the possibility of lake fish foraging

some distance upstream could provide the gra-

dient in predation pressure. The importance of

ducks as mollusk predators is well known

(Malone, 1965; Thompson, 1973). de Bernardi et

al. (1978) attribute substantial modification of

population structure to predation by ducks, and

Price (1957) has shown the importance of lake

fish predation on viviparids. Small snails with

their weaker shells would be subject to higher

predation rates than large snails. In other

words, snails that survive to a certain size have

escaped a major source of mortality (i.e., preda-

tion). These snails, relatively few in number,

would not be subjected to high intraspecific com-

petition and would grow to a relatively large

size. That stunting is occurring upstream might

also be inferred from the fact that females get

larger faster than males as we sample further

and further downstream. Since females seem to

have higher growth rates and greater reproduc-

tive energy requirements (because of vivipar-

ity), they may be more easily stunted in the

more crowded upstream habitats. Conversely,

under conditions of lower density and presumed

higher detritus deposition downstream, females

may be freer to express their genetically deter-

mined faster growing rates. The above specula-

tion obviously suggests a variety of future

studies. These would include analyses of the

relative organic content and depth of sediments

in the different stream habitats. In addition, it

would be beneficial to observe the feeding

behavior of potential predators, and to actually

examine their stomach contents. Furthermore,

predator and competitor exclusion pens could be

set up in the various habitats to test the actual

effects of these factors. Finally, laboratory and

field growth experiments would be invaluable in

testing our hypotheses.

Acknowledgments

The authors are grateful to Phillip Davis and

Donald House for pointing out the existence of

this population, and Gregory Panos, III, for help

with collecting the snails. Theodore Herzog of

our Computer Center was especially helpful in

processing the data. We are particularly in-

debted to Dr. Richard W. Dapson for his sub-

stantial assistance in the statistical analysis of

these data and to Dr. Eugene Studier for

critically reading the manuscript. The research

for this project was assisted by grants from the

Faculty Development Fund of the University of

Michigan-Flint.

LITERATURE CITED

Annandale, N. and R. B. S. Sewell. 1921. The banded pond

snail of India. Rcc Indian Mus. 22:217-292.

Browne, R. A. 1978. Growth, mortality, fecundity, biomass,

and productivity of four lake populations of the proso-

branch snail, Viviparus georgianus. Ecology 59:742-750.

Buckingham, M. J. and D. E. Freed. 1976. Oxygen consump-

tion in the prosobranch snail Viviparus eontectoides

(Mollusca: Gastropoda) -II. Effects of temperature and

pH. Comp. Biochem, Physiol. 53A:249-252.

Burla, H. 1972. Die Abundanz von Anodonta, Unio pic-

torum, Viviparus a tor. Lymnaea auricularia und Lym-

naea ovata in Zurichsee, in Abhangigkeit von der Wasser-

tiefe und zu verschiedenen Jahreszeiten. Vierteljahrs.

Naturforsch. Ges, Zurich, 117:129-151.

Clench, William J. 1962. a catalogue of the Viviparidae of

North America with notes on the distribution of I 'i vipa rus

georgianus Lea. Occ. Papers Moll. 2:261-287; 385-412.

Davis, P. B. and H. K. Fenner. 1977. A simple technique for

predicting the biomass of a prosobranch snail. Comp.

Biochem. Physiol. 56A:127-128.

de Bernardi, R., 0. Ravera. and B. Oregioni. 1976. Demo-

graphic structure and biometrie characteristics of Vivi-

parus ater Cristofori and Jan (Gasteropoda: Proso-

branchia) from Lake Alserio (Northern Italy). Jour. Moll.

Studies 42:310-318.

Fitch, D. D. 1975. Oxygen consumption in the prosobranch

snail Viviparus eontectoides (Mollusca: Gastropoda) -I.

Effects of weight and activity. Comp. Biochem. Physiol

51A:815-820.

1976. Oxygen consumption in the prosobranch

snail Viviparus eontectoides (Mollusca: Gastropoda) -III:

Effects of light. Comp. Biochem. Physiol. 54A:253- 257.

Fretter, V. and A. Graham. 1978. The Prosobranch Molluscs

of Britain and Denmark, Part 3. Jour. Moll. Stiniirs.

Suppl. 5:101-152.

Harman, W. N. 1972. Benthic substrates: Their effect on

fresh-water Mollusca. Ecology 53:271-276.

Hyman, L. H. 1967. The Invertebrates: Vol VI. Mollusca /.

McGraw-Hill Book Co.. N.Y. 1-792 p.

Imlay, M. J., J. W. Arthur, B. J. Hailigan, and J. H. Stein-

metz. 1981. Life cycle of the freshwater snail Campeloma

decisum (Viviparidae) in the laboratory. The Nautilus

95:84-88.

Jokinen, E. H. 19.S2. Cipaugojialudiua chinensis (Gastro-

poda: Viviparidae) in North America, review and update.

The Nautilus 96:89-95.

Malniie. (' I; 1965 [)i persal of aquatic gastropods via the

intestinal tract of water birds. Tk Nautilus 78:135-139.

Pianka, E. R. 1974. Evolutionary Ecology. Harper & Row,

Publishers, N.Y. viii, 1-356 p.

Plinski. M., W. Lawacz, A. Stanczykowska, and E. Magnin.

1978. Etude quantitative et qualitative de la nourriture

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 53

des Viviparus malleolus (Reeve) (Gastropoda, Proso-

branchia) dans deux lacs de la region de Montreal. Can.

Jour. Zool. 56:272-279.

Price, J. H. 1957. A study of the food habits of some Lake

Erie fish. U. S. Fish and Wildlife Service Report No. 837,

1-105 p.

Samochwalenko, T. and A. Stanczykowska. 1972. Fertility

differentiation of two species of Viviparidae (Viviparus

fasciatus Mueller and V. viviparus L.) in some en-

vironments. Ekilogia Polska 20:479-492.

Stanczykowska, A., E. Magnin, and A. Dumouchel. 1971.

Etude de trois populations de Viviparus malleatus (Reeve)

(Gastropoda, Prosobranchia) de la region de Montreal. I.

Croissance, fecondite, biomasse et production annuelle.

Can. Jour. Zool. 49:1431-1441.

Stanczykowska, A., M. Plinski, and E. Magnin. 1972. Etude

de trois populations de Viviparus malleatus (Reeve)

(Gastropoda, Prosobranchia) de la region de Montreal. II.

Etude qualitative et quantitative de la nourriture. Can.

Jour. Zool, 50:1617-1624.

Studier, E. H. and G. L. Pace. 1978. Oxygen consumption in

the prosobranch snail Viviparus contectoides (Mollusca:

Gastropoda) -IV. Effects of dissolved oxygen level, star-

vation, density, symbiotic algae, substrate composition

and osmotic pressure. Comp. Biochem. Physiol. 59A:

199-203.

Thompson, D. 1973. Feeding ecology of diving ducks on

Keokuk Pool, Mississippi River. Jour. Wildlife Manage-

ment 37:367-381.

Thompson, Fred G. 1985. Fresh Water Snails of Florida -A

Manual for Identification. University of Florida Press. 94

pp., 193 figs.

Vail, V. A. 1978. Seasonal reproductive patterns in 3

viviparid gastropods. Malacologia 17:73-97.

Van Cleave, H. J. and L. G. Lederer. 1932. Studies on the

life cycle of the snail Viviparus contectoides. Jour. Morph.

53:499-522.

van der Schalie, H. 1965. Observations on the sex of

t'umpeloma (Gastropoda: Viviparidae). Occ. Paps. Mus.

Zool. Univ. Mich, 641:1-9.

Young, M. R. 1975. The life cycle of six species of freshwater

molluscs in the Worcester-Birmingham Canal. Proc.

Malawi, Soc. Land. 41:533-548.

MODERN METHODS USED TO AGE OCEANIC BIVALVES

John W. Ropes

National Marine Fisheries Service

Northeast Fisheries Center

Woods Hole Laboratory

Woods Hole, MA 02543

ABSTRACT

Modern techniques of thin- sectioning chondrophores and the preparation of

acetate peels of sectioned valves are described that expose internal age/growth

structures of two commercially important U.S. oceanic bivalves, Spisula and

Arctica. The application of the methods in specific studies is reviewed. Verifica-

tion of annual age marks was based on mark-recapture experiments and length

frequency analyses for both species.

New methods have been under investigation

by the Northeast Fisheries Center since the

mid-1970's for determining the age and growth

characteristics of the Atlantic surf clam, Spisula

solidissima (Dillwyn), and ocean quahog,

Arctica islandica (Linne), bivalves that supply

the bulk (79% in 1983) of the meats for clam pro-

duction in the United States. Goals of the inves-

tigation were that the methods produce accu-

rate age determinations and be efficient, since

about 1,500 shell specimens of each species may

be taken during annual surveys. Age determina-

tions on a timely basis are specifically needed

for evaluations of age composition in assess-

ment studies of the populations.

Bands or rings form annually on the external

valve surface of some bivalves, much like rings

found in tree trunks, and have been used to

determine age (Lutz and Rhoads 1980). Similar

bands appear on the valves of young surf clams

and ocean quahogs up to about 15 years of age,

but with increasing age and size the earlier

bands are often obliterated by erosion and later

54 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

bands become too crowded together at the valve

margin for definite separation, even under

microscopic examination. Confusing, unverifi-

able and incomplete records are inevitable when

such poorly defined shell features are used for

age analysis. Thus, the use of such a general

method for critical studies is precluded by the

lack of accuracy in age determinations.

Specific internal shell deposits that form an-

nually have been found in other bivalves (Lutz

and Rhoads 1980). They are considered to be

relatively unaffected by external conditions

causing erosion, but require care in exposing the

deposits and critical microscopic examination.

Therefore, methodologies were developed for

examining such deposits in the shells of surf

clams and ocean quahogs.

Surf Clam Method

Preliminary examinations of internal age/

growth features in the valves of surf clams were

begun in 1975. Such examinations seemed justi-

fied by the presence of thin, dark lines seen

alternating with broader, white growth incre-

ments in fossilized valves. Whole surf clam

valves were cut in about one-half hour from the

beginning (umbo) to the end of a clam's life at

the valve margin using a diamond-impregnated

saw blade (Fig. 1). The cut edges were then

polished to remove saw marks and enhance the

distinctive dark lines that were suspected to be

age annuli. These lines curved down and back

toward the umbo of a valve and became increas-

ingly attenuated at the myostracal layer from a

more prominent beginning beneath external

bands. The myostracal layer separated inner

and outer shell layers in these valves. The lines

were validated as annual age marks by marking

some surf clams for release and recovery at

Chincoteague Inlet, VA (Ropes and Merrill

1970; Jones et al. 1978). Ambrose et al. (1980),

Jones (1980, 1981a and b, 1983), Jones et al.

(1983), and Arthur et al. (1983) report studies

based on the annual periodicity of these lines in

surf clams.

Age determinations of whole valves required

careful microscopic examination of the cut sur-

faces. Holding the valve level and in focus under

the microscope proved difficult and even more

frustrating when trying to make growth meas-

urements. In addition, the cutting, polishing and

cc

3

s

8

VENTRAL

DORSAL D

DIRECTION OF CUT

VENTRAL

FIG. 1. Sketches of internal valve features and direction of

cut (dashed line) (a) to remove part of the chondrophore

(lightly stippled area) from a surf elam, S/iisuln vilitHssimn,

(from Ropes and O'Brien 1979), and (b) to completely section

the left valve of an ocean quahog, Arctica islandica, and a

unique hinge tooth bearing age lines (from Ropes 1982).

examination procedures required about one

hour per specimen and were considered to be ex-

cessively time consuming. Nevertheless, growth

lines in the valves were clearly exposed and this

was a necessary procedure used in establishing

a basis for a more efficient method to follow.

Ropes and O'Brien (1979) developed a new

method of exposing age lines in a part of the

hinge called the chondrophore (Fig. 1). This por-

tion of the shell can be cut in less than a minute

using two diamond-impregnated saw blades

spaced 2 mm apart and is then easily broken

away from the shell by finger pressure. The

piece is glued onto a glass slide for thin-

sectioning, which usually takes less than 15

minutes and results in about a 0.25-mm-thick

slice. Age lines in the thin section are translu-

cent when viewed with transmitted light;

growth increments between the lines are

opaque. In photographic enlargements the

translucent lines appear as dark lines and are

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 55

FIG. 2. Photographic enlargements of thin-sectioned chon-

drophores from surf clams: (a) 8 years old and 139 mm in

shell length; and (b) 13 years old and 137 mm in shell length.

The first annulus formed in the life of a surf clam is some-

times faint (an arrow points to a bold one in the chondro-

phore of clam a). The most recent annulus at the marginal

edge of these chondrophores was not completely formed.

the annuli (Fig. 2). Linear measurements from

the umbo to growth bands in the chondrophore

regressed upon the valve length of correspond-

ing external bands for a sample of surf clams,

using least squares technique, resulted in a

relatively high correlation coefficient (r=0.97).

The regression equation (y = 22.739 + 59. 063x)

accounted for 94% of the variation between the

two measurements. Thus, annuli in the chondro-

phores of surf clams correspond in number and

relative location with those in the valve. This

refinement of the basic method of exposing in-

ternal age lines in surf clams produces consis-

tent age determinations, measurements of

growth throughout the life of a clam, and

records for future reference.

Ocean Quahog Method

Age determinations of ocean quahogs were

significantly advanced by the recommendations

of Thompson et al. (1980a and b) and Jones

(1980) that the acetate peel technique be used.

In the technique developed at the NEFC, Woods

Hole Laboratory, left valves are routinely used

because they have a unique, single tooth con-

taining valuable age information useful in con-

firming counts made from the valve. The steps

in preparing valves include sectioning (Fig. 2),

bleaching to remove the thick periostracum,

embedding in epoxy, polishing, and etching the

cut surface with a 1% HC1 solution (Ropes 1982).

Then sheet acetate is applied with acetone to

melt the acetate and peel off after the acetone

completely evaporates. Except for the one

minute etching period, the sectioning (15-30

min), embedding (overnight hardening), polish-

ing (2-3 hr) and drying (1 hr) periods are time

consuming. The production of a peel is neces-

sary, since the thin age annuli are microscopi-

cally indistinct on the external valve surface or

in the cut surface of an ocean quahog shell.

Although age annuli and growth increments

are reproduced much more clearly in a peel than

in the cut surface of the shell, it must be exa-

mined microscopically and the many crowded

annuli in old quahogs are a challenge to count. It

is not unusual to have quahogs that are about

100 years old.

Various experimental evidence suggests that

annuli are formed in the shells of ocean quahogs

(Thompson et al. 1980a and b, Jones 1980) in-

cluding the use of radiometric techniques

(Turekian et al. 1982, Bennett et al. 1982). A

NMFS marking experiment substantially sup-

ported such a hypothesis. Specimens were

marked for release and recapture at a 53 m deep

site off Shinnecock Inlet, Long Island, NY. The

marks were made by two carborundum discs

spaced 2 mm apart and mounted on an electric

grinder. This produced distinctive parallel

grooves at the ventral edge of about 42,000

clams released in 1978. Marked quahogs have

been recovered annually thereafter.

Murawski et al. (1982) developed a growth

rate relationship for marked ocean quahogs

(59-104 mm in shell length) recaptured one year

after release (SL,+, = 2.081 1 + 0.9802 SL,). Back-

calculated growth measurements at age of un-

marked quahogs (19-60 mm in shell length) cap-

tured in the vicinity of the marking site resulted

in an age/growth relationship for younger,

smaller specimens [SL = 75.68-81.31 (0.9056)'].

Growth in length described by these equations

provided additional evidence for the growth rate

of the species at the Long Island site.

Ropes et al (in press) found definite prismatic

microstructures, considered to be the basis for

the formation of annuli, that separated growth

increments of predominantly homogenous mi-

crostructures. Although the microstructures are

only visible by scanning electron microscopy,

light microscope examinations of acetate peels

56 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

FIG. 3. Photomicrographs of acetate peels showing growth

and annuli at the valve margins of ocean quahogs marked for

release off Long Island, NY, in 1978 and recovered two

years later, (a) a 15-year-old, 60 mm in shell length clam, and

(b) a 95-year-old, 92 mm in shell length clam. An arrow

points to an annulus formed soon after marking. Only one

additional annulus was formed thereafter by both clams, and

it separated two increments of shell growth accreted after

marking. The flattened area in (b) was produced by the

notching operation.

clearly revealed the annual periodicity of annuli

in small and large marked quahogs (Fig. 3).

General Comments

The growth of ocean quahogs is characteris-

tically slow except during the first 20 years of

life (Fig. 4). Quahogs of about 100 mm in shell

length are about 100 years of age and are com-

mon in the population. Maximum shell length

approaches 140 mm, but large size may not in-

dicate very old age (Ropes and Murawski 1983).

A specimen 107 mm long has been found to have

a minimum of 221 growth lines in its valve and it

was alive when caught. A longevity of at least

225 years surpasses known estimates for other

bivalves. Ropes and Pyoas (1982) found evi-

dence for geographic variation in the growth of

ocean quahogs. Quahogs from Georges Bank

were younger than specimens of equal length

from off Long Island, NY, or off Sable Island,

Canada. In a comparison of growth data for

Georges Hank quahogs with marked quahogs

from off Long Island, a much slower rate was

<J3

s

150

100 -

10 20

v

40 50 60 70

AGE (YEARS)

80 90 100

FIG. 4. General age (in years) and growth relationship for

surf clams (Spisula solidissima) (Ropes 1980) and ocean

quahogs (Arrhrn islinnlira) ( Murau ski rt nl. 1982).

obtained for the latter area. Ocean quahogs ap-

pear to be reproductively viable throughout the

long life span (Thompson et al. 1980a). Ocean

quahog growth contrasts sharply with the faster

growing surf clam. It commonly attains a shell

length of about 165 mm in 10 years (Ropes

1980). The maximum recorded shell length of a

surf clam is 226 mm and longevity is estimated

to be about 35 years. Growth lines similar to

those in S. solidissima were found in Stimpson's

surf clam, S. polynyma, another species in the

family Mactridae. This suggests that the method

of preparing surf clams for ageing may have ap-

plication for other species with well developed

chondrophores. Surf clams are probably also

reproductive throughout their life span. Spawn-

ing has been implicated as the possible stimulus

for deposition of growth lines in both species

Vol. 99 (2-3)

April 29, 1985

THE NAUTILUS 57

(Thompson et al. 1980a, Jones et al. 1978).

Population assessment studies integrate age-

ing of large numbers of specimens throughout

the extensive distribution of both species in the

Middle Atlantic Bight and off New England.

Samples of surf clam shells for age analysis are

routinely taken during annual surveys of the

resource in the Middle Atlantic Bight and off

New England. The refined method serves effi-

ciently in processing the samples collected dur-

ing a survey without sacrificing accuracy of age

determinations. The age data provide valuable

information on growth rates and age composi-

tion in assessment studies of this important

commercial bivalve. The collection of similar

data for ocean quahogs is thwarted by the labor

intensive nature of shell preparation and micro-

scopic examination. Nevertheless, ocean quahog

samples from localized areas are under in-

vestigation to gain insight into the age/growth

phenomena. Age data are an integral part of

management plans regulating both resources

that have been developed by the Mid-Atlantic

Fishery Management Council.

LITERATURE CITED

Ambrose, W. G., Jr., D. S. Jones and I. Thompson. 1980.

Distance from shore and growth rate of the suspension

feeding bivalve, Spisula solidissima. Proc. Natl. Shellfish.

Assoc. 70:207-215.

Arthur, M. A., D. F. Williams and D. S. Jones. 1983. Sea-

sonal temperature-salinity changes and thermocline

development in the Mid- Atlantic Bight as recorded by the

isotopic composition of bivalves. Geol. 11:655-659.

Bennett, J. T., K. K. Turekian. W. J. Shaul and J. W. Ropes.

1982. Using natural radionuclides to measure shell growth

rates and ages of the bivalves Arctica islandica (Linne)

and Panope generosa Gould. Abstracts, 1981 An. Meeting,

Natl. Shellfish Assoc, hi: Jour. Shellfish Res. 2:88-89.

Jones, D. S. 1980. Annual cycle of shell growth increment

formation in two continental shelf bivalves and its paleo-

eeologic significance. Paleobiol. 6:331-340.

1981a. Repeating layers in the molluscan shell

are not always periodic. Jour. Pcdeont. 55:1076-1082.

1981b. Annual growth increments in shells of

Spisula solidissima record marine temperature variabil-

ity. Science 211(4478):165-167.

1983. Sclerochronology: Reading the record of

the molluscan shell. Amer. Sci. 71:384-391.

Jones, D. S., I. Thompson and W. Ambrose. 1978. Age and

growth rate determinations for the Atlantic surf clam,

Spisula solidissima (Bivalvia: Mactracea), based on in-

ternal growth lines in shell cross-sections. Mar. Biol.

47:63-70.

Jones, D. S., D. F. Williams and M. A. Arthur. 1983. Growth

history of Spisula solidissima Dillwyn as revealed by

oxygen isotopes and sclerochronology. Abstracts, 1981

An. Meeting, Natl. Shellfish. Assoc. In: Jour. Shellfish

Res. 2:99.

Lutz, R. A. and D. C. Rhoads. 1980. Growth patterns within

the molluscan shell, an overview. In: Rhoads, D. C. and

R. A. Lutz (eds), Skeletal Growth of Aquatic Organisms.

Plenum Press, N.Y. 750 p.

Murawski, S. A., J. W. Ropes and F. M. Serchuk. 1982.

Growth of the ocean quahog, Arctica islandica, in the

Middle Atlantic Bight. Fish. Bull. 80:21-34.

Ropes, J. W. 1980. Biological and fisheries data on the

Atlantic surf clam, Spisula solidissima Dillwyn. U.S.

Dept. Comm... NOAA. NMFS. Tech. Ser. Rep. No. 24. 88 p.

1982. Procedures for preparing acetate peels of

embedded valves of Arctica islandica for ageing. U.S.

Dept. Comm... NOAA. NMFS. NEFC. Woods Hole Labora-

tory Ref Doc. No. 82-18. 8 p.

Ropes, J. W. and A. S. Merrill. 1970. Marking surf clams.

Proc. Natl. Shellfish. Assoc. 60:99-106.

Ropes, J. W. and L. O'Brien. 1979. A unique method of

ageing surf clams. Bull. Amer. Malacological Union. Inc.,

p. 58-61.

Ropes, J. W. and D. Pyoas. Preliminary age and growth

observations of ocean quahogs, Arctica islandica Linne,

from Georges Bank. ICES/C.M. 1982/K:15, Shellfish

Comm., 6 p.

Ropes. J. W. and S. A. Murawski. 1983. Maximum shell

length and longevity in ocean quahogs, Arctica islandica

Linne. ICES/C.M. 1983/K:32, Shellfish Comm., 8 p.

Ropes, J. W., D. S. Jones, S. A. Murawski, F. M. Serchuk

and A. Jearld, Jr. Documentation of annual growth lines

in ocean quahogs, Arctica islandica Linne. Fish. Bull.

(In Press).

Thompson, I., D. S. Jones and D. Deribelbis. 1980a. Annual

internal growth banding and life history of the ocean

quahog Arctica islandica (Mollusca: Bivalvia). Mar. Biol.

57:25-34.

Thompson, I., D. S. Jones and J. W. Ropes. 1980b. Advanced

age for sexual maturity in the ocean quahog Arctica

islandica (Mollusca: Bivalvia). Mar. Biol. 57:35-39.

Turekian, K. K.. J. K. Cochran, Y. Nozaki, I. Thompson

and D. S. Jones. 1982. Determination of shell deposition

rates of Arctica islandica from the New York Bight using

natural —8Ra and 228Th and bomb-produced 14C. Limnnl.

Oceanogr. 27:737-741.

58 THE NAUTILUS

April 29, 1985

Vol. 99 (2-3)

TWO NEW SPECIES OF FAVARTIA FROM THE WEST

PACIFIC OCEAN (GASTROPODA: MURICIDAE)

Anthony D'Attilio and Barbara W. Myers

Department of Marine Invertebrates

San Diego Natural History Museum

San Diego, CA 92101

ABSTRACT

Two new species ofmuricids, Favartia (Murexiella) rosamiae and F. (M.) leonae

are described from the Philippines and Ryukyu Islands, and compared with

related species.

Through the courtesy of several shell collec-

tors, we have recently obtained for the collec-

tion of the San Diego Natural History Museum,

specimens of two undescribed species of muricid

gastropods. One of the new species, Favartia

(Murexiella) rosamiae has been confused with F.

cyclostoma (Sowerby, 1841). The redescription

of F. cyclostoma and selection of a lectotype was

discussed by D'Attilio and Myers (1984).

Institutional abbreviations used in this paper

are: AMNH = American Museum of Natural His-

tory, New York, New York, and SDNHM = San

Diego Natural History Museum, San Diego,

California.

I '.)71

spire

MURICIDAE Rafinesque, 1815

MURICOPSINAE Radwin and D'Attilio,

Genus Favartia Jousseaume, 1880

Subgenus Murexiella

Clench and Perez Farfante, 1945

Favartia (Murexiella) rosamiae

new species

Figs, l to 6

Shell moderately broad, fusiform;

elongate; five to six postnuclear whorls;

shoulder angulate on spire; suture impressed.

Protoconch of holotype eroded; protoconch of

paratype B with three and one-quarter conical

transparent whorls. Aperture subovate; outer

lip crenulate and fluted; inner lip moderately

erect anteriorly. Anal sulcus weakly defined.

Siphonal canal long, narrowly open, broad

above, tapering terminally, recurved and tube-

like. Two to four well-preserved former canal

terminations on the siphonal fasciole. Four

varices on body whorl, five on penultimate

FIGS. 1 and 2. Favartia (Murexiella) rosamiae D'Attilio and

Myers. Dorsal (1) and apertural (2) views of holotype.

Dimensions 17.7 mmxl2.2 mm. SDNHM 80742.

KKIS, :-; and 4. Fnnirtiti (Murrxielln) rusamiae D'Attilio

and Myers. Dorsal (3) and apertural (4) views of paratype A.

Dimensions 15 mmx 10.7 mm. SDNHM 85101.

whorl; body whorl varices thick, beginning at

suture above shoulder and descending anterior-

ly to the canal. Spiral sculpture consisting of six

strong cords terminating in spines; one or two

cords above the shoulder, the strongest cord and

spine at the shoulder and three secondary cords

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 59

FIG. 5. Camera lucida drawing of the protoconch of F. (M.)

rosamiae, paratype B. SDNHM 82288. Greatly enlarged.

FIG. 6. Detail drawing of the radula of

F. (M.) rosamiae. Greatly enlarged.

below. Two additional cords on the canal. Cords

separated on the dorsal side by a strongly

depressed or excavated area. Cords covered by

blunt appressed scales; a portion of each scale

bulges beyond the width of the cord lending the

cord a toothed or serrated appearance on both

anterior and posterior sides. Cords and spines

on the outer lip connected by a flange and the

spiny extension of the spiral cords terminate

well beyond the flange. Intervarical areas on the

body whorl broadest between the final varix and

the preceeding one. The scabrous cords strong

on the varices and obsolete on the final inter-

varical area. Cords and scales microscopically

spirally grooved with the terminal portion of the

scales convexly scalloped. The radula ribbon

long and narrow with about 110 rows of teeth.

The rachidian plate with five strongly project-

ing, stocky short cusps, the central cusp extend-

ing above the rachidian plate.

Color: Holotype-dull white with four narrow

brown bands visible within the aperture;

siphonal canal a pale-orange. Color variability

noted as follows: creamy white to tan occa-

sionally with broad brown or red bands exterior-

ly. The siphonal canal either white or tan, occa-

sionally orange or deep coral-red.

Type Locality: Cebu, Bohol Straits, Philippine

Islands, 75-100 meters depth. Paratypes from

Balut Island, Mindanao, Philippine Islands;

Cebu, Bohol Straits, Philippine Islands;

Okinawa, Ryukyu Islands, Japan. Collected in

1984,.

Dimensions: Holotype 17.7 mm in length,

width 12.2 mm from Cebu, Bohol Straits, Philip-

pine Islands (SDNHM 80742); paratype A, 15

mm x 10.7 mm from Okinawa, Ryukyu Islands,

Japan (SDNHM 85101); paratype B. 8.8 mmx

6.2 mm from Cebu, Bohol Straits, Philippine

Islands (SDNHM 82288). Seven paratypes from

Cebu, Bohol Straits, Philippine Islands

(SDNHM 80742) with the following measure-

ments: 13.5 mmx 10.4 mm; 13.8 mmx9.0 mm;

13.4 mmx 9.7 mm; 12.1 mmx 8.0 mm; 10.5 mm

x7.3 mm; 10.2 mmx 7.3 mm; 9.5 mmx 6.2 mm.

Twelve paratypes from Okinawa, Japan

(SDNHM 81639) with the following measure-

ments: 15.7 mmx 11.3 mm; 13.4 mmx9.8 mm;

12.1 mmx9.0 mm; 12.4 mmx8.5 mm; 11.1 mm

x9.6mm; 12.1 mmx8.6mm; 11.6 mmx7.7 mm;

11.3 mmx8.5 mm; 11.5 mmx7.1 mm; 11.5

mmx7.7 mm; 10.6 mmx8.5 mm; 9.8 mmx7.6

mm. Twelve paratypes from Balut Mindanao

Island, Philippine Islands (SDNHM 84345) with

the following measurements: 12.3 mmx 8.4 mm;

12.7 mmx7.5 mm; 12.5 mmx8.3 mm; 11.8 mm

x 8.2 mm; 12.3 mmx 7.5 mm; 11.5 mmx 8.3 mm;

11.5 mmx8.4 mm; 11.3 mmx8.0 mm; 10.7 mm

x 7.6 mm; 10.8 mmx 7.7 mm; 11.3 mmx 7.5 mm;

11.3 mmx8.5 mm.

Two paratypes from Cebu, Bohol Straits,

Philippine Islands are deposited in the American

Museum of Natural History (AMNH 213556).

We are depositing two paratypes each in the

following institutions: two paratypes in the

60 THE NAUTILUS

April 29, 1985

Vol. 99 (2-3)

Academy of Natural Sciences of Philadelphia,

from Cebu, Bohol Straits, Philippine Islands,

14.3 mm x 9.0 mm; 13.3 mm x 8.6 mm; two para-

types in the U. S. National Museum, from Cebu,

Bohol Straits, Philippine Islands 13.4 mm x 7.4

mm; 10.7 mm x 8.8 mm; two paratypes in the

Los Angeles County Museum from Balut, Min-

danao Island, Philippine Islands 12.7 mm x 9.2

mm; 12.1 mm x 8.1 mm; two paratypes in the

British Museum (Natural History) from Balut,

Mindanao Island, Philippine Islands 14.5 mm

x 11.0 mm; 12.5 mmx9.2 mm.

Etymology: This species is named for Rose

D'Attilio, wife of the senior author, who first in-

troduced him to seashells by sending him a box

of shells from Florida in 1938. The Italian "rosa

mia", which means my Rose, is latinized into the

genitive form ending.

Discussion: Comparison is made with Favar-

tia cirrosa (Hinds, 1844), the shell of which is

broader with a shorter spire and possesses num-

erous strong lirations within the aperture; the

varices are sharply recurved and number six on

the body whorl, eight on the penultimate whorl,

and nine on the whorl preceding the penultimate

whorl. This increase in the number of varices on

the moderately short spire tends to obscure the

suture. The spire is higher and better defined in

F. rosamiae, and the varices on the body whorl

number four or five. The protoconch of F. cir-

rosa consists of two and one-half whorls, both

whorls being the same diameter, while the pro-

toconch of F. rosamiae consists of three and

one-quarter smooth conical transparent whorls.

For further discussion ofF. cirrosa, a rare, long

poorly-known species, see D'Attilio (1981).

This new species has been confused with F.

cyclostoma (Sowerby, 1841). The well-defined

characters of F. cyclostoma have been treated

by D'Attilio and Myers (1984). Based on the

morphology of the syntypic material, F.

cyrloshiniti has a broader, heavier shell, the lee-

i'ii\ |>,> iif w hirh measures 24 mm ■ 1 7 mm.

FIGS. 7 and 8. Favartia (Murexiella) leonae D'Attilio and

Myers. Dorsal (7) and apertural (8) views of holotype.

Dimensions 14.2 mm x 11.5 mm. SDNHM 81638.

FIGS. 9 and 10. Favartia (Murexiella) leonae D'Attilio and

Myers. Dorsal (9) and apertural (10) views of paratype H.

Dimensions 13.1 mmxl0.6 mm. SDNHM 85109.

FIG. 11. Camera lueida drawing of the protoconch oIF. (M.)

leonae paratype D. SDNHM 85105. Greatly enlarged.

Favartia (Murexiella) leonae, new species

Figs. 7 tn 1 1

Shell broadly fusiform, shoulder angulate,

spire moderately high, suture impressed. Proto-

conch of holotype eroded; protoconch of para-

type D with 2V4 dull white blunt, convex whorls;

four to five postnuclear whorls. Aperture white.

ovate; inner lip erect anteriorly. Anal sulcus

directed to the left. Outer lip erect, crenulate,

reflecting the exterior spiral sculpture. Siphonal

canal broad above, narrowing and recurving

distally, and weakly open. Siphonal fasciole with

three scaly tubelike remnants of earlier canal

terminations. Four varices on body whorl with

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 61

the intervarical areas unequal. Five varices on

penultimate whorl. Two weak spiral cords on

spire strongly developed only on the back slope

of the varix. Five to seven spiral cords on body

whorl, weakly defined between varices and

strongly developed on receding portion of the

varices. The first two to three cords developing

into elongate spines on the varices except on the

apertural varix where all cords are of equal size.

On the final varix the moderately projecting

cords connected by a continuous flange which

abuts the penultimate whorl. Growth striae on

the body whorl weakly developed. The leading

side of the apertural flange with about four to

seven well developed lamellae in the interspaces

between the cords.

Color: Pale rose shell with spines a much

lighter hue. Occasionally (holotype) with a broad

band of deep coral red.

Type locality: Bolo Point, Okinawa, Ryukyu

Islands, Japan from 55 meters depth. Paratypes

from Okinawa, Ryukyu Islands, Japan, and

from Bohol Straits, Philippine Islands.

Dimensions: Holotype 14.2 mm in length 11.5

mm in width from Okinawa, Japan, (SDNHM

81638); paratype A, 14.4 mm x 10.2 mm from

Okinawa, Japan (SDNHM 85102); paratype B,

10.7 mm x 8.6 mm from Okinawa, Japan

(AMNH 213555); paratype C, 12.5 mm x 8.7 mm

from Okinawa, Japan (SDNHM 85104); para-

type D, 11.1 mmx7.8 mm from Bohol Straits,

Philippine Islands, (SDNHM 85105); paratype

E, 14.3 mmx 10.7 mm from Okinawa, Japan,

(SDNHM 85106); paratype F, 14.2 mmx 11.0

mm from Okinawa, Japan, (SDNHM 85107);

paratype G, 14.0 mmx 9.8 mm from Okinawa,

Japan, (SDNHM 85108); paratype H, 13.1 mm

xl0.6 mm from Okinawa, Japan, (SDNHM

85109); paratype I, 12.5 mmx 9.2 mm (SDNHM

85110).

Etymology: Named for Leona Bellin, wife of

Phillip Bellin, who first collected specimens of

Favartia (Murexiella) leonae from Okinawa,

Ryukyu Islands, Japan, used in this study.

IHscnssudi: This species bears little <'<>m-

parison with any of its congeners, with the ex-

ception of an unnamed species which is more

widespread and of a larger size, under study at

the present time from the western Pacific. The

lack of shoulder spines on the apertural varix is

a consistent character in the specimens studied.

Acknowledgments

We wish to thank the following friends who

contributed specimens for our study: Phillip

Bellin of Okinawa, Japan; Robert Yin of La

Jolla, California; Donald Pisor of San Diego,

California; Edward Swoboda of Los Angeles,

California; Robert Foster and Charles Glass of

Santa Barbara, California. We are grateful to

David K. Mulliner for the photography used in

this paper and Dr. Hans Bertsch for his

assistance with the Latin orthography. Dr.

William K. Emerson (AMNH) kindly reviewed

the manuscript.

LITERATURE CITED

Clench, W. J. and I. Perez Farfante. 1945. The genus .1/// ru-

in the western Atlantic. Johnsonia l(17):l-56, pis. 1-28.

D'Attilio, A. 1981. The rediscovery of Murex cirrosus Hinds,

1844. TheFestivus 13(4):46-51. figs. 1-8.

DAttilio, A. and B. W. Myers. 1984. Redescription of Favar-

tia cyclostoma (Sowerby, 1841) and selection of a lecto-

type, with illustrations of some related species (Muricidae).

TheFestivus 16 (11):116-122, figs. 1-12.

Hinds, R. B. 1844. The Zoology of the Voyage of HMS

Sulphur . . ., vol. II, 72 pp., 21 pis.

Jousseaume. F. 1880. Division methodique de la famille des

Purpurides. Le Natural iste 42:335-36.

Radwin, G. E. and A. DAttilio. 1971. Muricacean supraspe-

cific taxonomy based on the shell and the radula. The Echo

4:55-67, 23 figs.

Rafinesque, C. S. 1815. Analyse de la nature <m tableau de

univers et des corps organises. Barravecchia, Palermo.

Sowerby, G. B. II. 1841. Description of some new species of

Murex, principally from the collection of H. Cuming Esq.

1'roe. Zool. Sue. London for 184(1: 137-147.

62 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

A RAPID METHOD FOR SLIDE MOUNTING OF MINUTE RADULAE,

WITH

A BIBLIOGRAPHY OF RADULA MOUNTING TECHNIQUES

Paul S. Mikkelsen

Department of Benthic Ecology

Harbor Branch Foundation, Inc.

R.R. 1, Box 196

Ft. Pierce, FL 33450

ABSTRACT

A method for rapidly cleaning, staining and mounting many minute radulae is

detailed through the use of many- chambered, deep-well slides, together with the use

of CMC as a combined stain/mounting medium. A bibliography of literature on

mounting radulae for both light and scanning electron microscopy is provided.

Previous methods for preparing radulae have

generally dealt with fairly large or macroscopic

radulae. Most methods (e.g., Bowell, 1915;

Gascoigne, 1975; Meeuse, 1950; Radwin, 1969)

involve multiple handlings of the radula, i.e.,

cleaning, rinsing, possibly several steps of stain-

ing, and bringing it up through a series of solu-

tions prior to preparation for mounting. How-

ever, these methods are inappropriate and time-

consuming for extremely minute radulae, and

most often result in their loss.

The simplest methods for mounting very small

radulae have been those accomplished on a

single microscope slide. Such methods were sug-

gested by Binney (1885:45), Beecher (1888:11),

Verdcourt (1946), Meeuse (1950a:36), and later

by Turner (1960), and Basch (1961). However,

this procedure requires that each radula be pro-

cessed individually and consecutively, requiring

much time to process several radulae.

The method described herein has two advan-

tages: (1) many radulae can ber processed at

nearly the same time, and (2) loss of extremely

minute radulae is avoided by handling each

radula only once, with the use of "CMC" (un-

abbreviated spelling unknown) as both a stain

and a mounting medium. Although use of CMC

for mounting radulae is not new, it has ap-

parently not been published, and is known pri-

marily to more established malacologists.

Advantages of the medium have been detailed

for use with snail genitalia (Michelson, 1960),

larval trematodes (Davis, 1964), and for larval

chironomids (Beckett and Lewis, 1982).

A bibliography of radula mounting techniques

for both scanning electron and optical

microscopy is provided.

Materials and Methods

CMC is a non-resinous, water-miscible mount-

ing medium available from Masters Chemical

Company, Inc., P.O. Box 2382, Des Plaines, Illi-

nois 60018. Of the two types of mounting media

offered, the faster-drying "CMC" series is highly

preferable over the slower-drying "CMCP"

series, for purposes described herein. The media

may be obtained in a high or low viscosity state,

with refractive indices ranging from 1.38-1.40

(see E.P.A., 1980). The material is available

pretinted with stain (aniline blue or acid fuchsin)

or colorless, to which one can add his own stain

if desired.

To dissolve all soft tissue, the entire animal or

only the odontophore of the animal (depending

on specimen size) is soaked for a day in 5-10%

NaOH placed in one marked well of a multi-well

Boerner slide (available through American

Scientific Products, 1430 Waukegan Rd.,

McGaw Park, Illinois 60085), or similar product.

By utilizing all of the wells of the Boerner slide,

many radulae can be prepared simultaneously.

Heating to accelerate the dissolving process is

disadvantageous because (1) excess heat may

adversely affect the radular structure (see:

Lindberg, 1977) and (2) high heat or boiling

usually causes varying degrees of flocculent

material to form in the NaOH, thus hindering

the relocation of extremely small radulae.

Vol. 99 (2-3)

April 29, 1985

THE NAUTILUS 63

The Boerner slide is then placed in a container

with a tight-fitting lid, into which has been

placed a paper towel moistened with water, thus

creating a humidity chamber which prevents the

fluid in the Boerner slide from evaporating. The

specimens are usually left to soak overnight, but

may be left several days. Slight warming would

accelerate the dissolving process.

At the completion of the dissolving process, a

radula is then located on the Boerner slide,

using a dissecting microscope. A toothpick or

other small probe is dipped into the stained

CMC, removed, and the excess allowed to drip

back into the bottle. The probe is then touched

to a clean microscope slide to apply a very small

portion (much less than a drop) of CMC. With an

extremely fine dissecting needle type of probe in

each hand, the radula is teased off the bottom of

the well and brought to the surface. The radula

is always manipulated by placing the probe(s)

under the radula and lifting; the radula is never

pinched with forceps or other tools. The micro-

scope is pre-focused to the fluid surface, or re-

adjusted if necessary.

The radula is guided onto the upper surface of

a submerged probe tip, using another probe as a

guide. The radula is then lifted out of the NaOH

and held stationary, directly above the well. The

Boerner slide is moved aside, and the micro-

scope slide is positioned such that the CMC on

the slide is directly under the held radula, both

within the field of view of the microscope. The

radula and focus are lowered simultaneously

such that one can see when the probe tip and

radula contact the CMC. When contact is made,

the second probe is used to ease the radula off

the first probe, if necessary, and into the center

of the CMC.

At this point, the procedure varies somewhat

for larger (but still small) radulae, and those

which are extremely small:

(A) With larger material and with the radula

now in a very small amount of CMC, it can be

manipulated, flattened, distorted, or dissected.

As the CMC begins to set, the radula (or por-

tions of it) can be placed in final position and

allowed to dry until quite firm. Should the CMC

begin to set prematurely, one has but to add a

very slight amount of water to the preparation

to gain more time. The CMC may turn slightly

opaque, but should clear fairly rapidly. A full

drop of stained CMC is then placed on the center

of a clean cover slip which is picked up and in-

verted to form a "hanging drop" of CMC on the

underside of the slip. The slip is then very slowly

(to avoid bubble formation) placed onto the slide

and radula. As an alternative, additional CMC

may be applied to the dry or nearly dry mount

(to fill depressions in the set CMC) and the cover

slip applied dry.

(B) Very small radulae cannot be manipulated

at this time, and should be kept wet (see below),

in a somewhat larger drop of CMC. In this case,

the cover slip may be applied dry, or with a

hanging drop of additional CMC. As the CMC

flows into position under the weight of the cover

slip, the smaller radula (if allowed to remain

wet) can be manipulated and kept toward the

center of the cover slip by applying slight

pressure on the edge of the cover slip toward

which the radula is traveling.

The radula is usually examined immediately,

and the number of radular rows are usually

counted at this time. Using low power of a com-

pound microscope, the desired location and

orientation of the still wet, smaller radula can be

attained by slight pressure on the cover slip. Ex-

treme pressure will cause the teeth to separate

from the radular membrane (which is often

desirable). Proper movement of the cover slip,

and/or prior manipulation, can attain a final

mount which has the radula partially folded over

itself and/or twisted, possibly with several teeth

dissociated from the radular membrane. This

reveals many different angles of the teeth, and

gives an observer the maximum information

from a slide mount . . . much more than if the

radula were simply flattened. The above mount-

ing procedure is then repeated for the remain-

ing radulae. Because the CMC does not dry

rapidly, once the cover slip is applied, several

radulae may be mounted on slides prior to ex-

amination of them with a compound microscope;

i.e., they can be processed in small groups to

conserve time.

With the radula in the proper position, and

with all movement of the radula and CMC

ceased, the slide is further examined with higher

magnification and/or allowed to dry for about 24

hours. At that time, the dried, excess CMC is

trimmed away with the aid of a scalpel (a curved

blade is preferable). Final cleaning is ac-

64 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

complished by wiping with a moist, lint-free

tissue. This trimming and cleaning is not only

cosmetic, but also provides clean surfaces to

allow a good "ringing" bond. The edge of the

cover slip is then sealed or "ringed" with clear

nail polish or other sutiable substance, twice, to

insure a good seal such that the mounting

medium will not evaporate.

Stains

Any suitable stain may be added to the color-

less CMC. The more desirable stains used have

been acid stains, Acid Fuchsin and Lignin Pink.

Pronticil dye works well (pers. comm. Joseph

Rosewater, 1984) and was used by Morrison

(1951). These particular stains have stained the

majority of the radula (many stains do not . . .

and sometimes these do not), leaving unstained

the tips of denticles of the older, enamelized

teeth or the entire older tooth. The bases of the

older teeth are often stained when the entire

tooth will not pick up the stain. The desired

stain may be added, in very small quantities,

directly to the clear CMC. CMC may be pur-

chased pretinted with acid fuchsin, but one may

wish to alter (probably increase) the concentra-

tion. Addition of enough acid fuchsin to attain a

translucent, cherry color in the mounting

medium is desirable. These acid stains, together

with an extremely slight addition of a basic stain

(especially methylene blue) to the CMC will

usually stain the entire radula quite well, in-

cluding older teeth and denticle tips. This com-

bination of stains (fairly heavy on the acid stain

and very light on the basic stain) maintains the

one-step stain/mounting technique, as well as

producing an entirely stained radula.

The combination of stains mentioned above

produces a radula of generally one color. For

cases in which the radula is large enough to be

handled with confidence, a dip in an appropriate

acid stain dissolved in water, a water rinse,

followed by a dip in an appropriate basic stain

dissolved in water can produce a radula with the

younger, chitinous teeth (and possibly older

teeth and/or the bases of them) stained one

color, while the older enamelized teeth are

stained a second color (see Meeuse, 1950:29).

From this point, the radula is given a final rinse

in water and can immediately be mounted using

the clear CMC. The effect of concentration and

type of stain varies with the type of radula, and

requires some experimentation to achieve the

desired effect.

Advantages

Becuase a small radula can be placed directly

from NaOH to the CMC stain/mounting medi-

um, the method has the advantage of a single

handling of minute radulae. This feature is

essential with extremely minute radulae which

are easily lost due to excessive handling. With

acid fuchsin stain in the mounting medium, the

radula is simultaneously stained and mounted;

therefore, use of water soluble CMC eliminates

rinsing the radula and carrying it through

several solutions of an alcohol or alcohol/xylene

series.

Since some clearing action is provided by the

CMC, the radula need not be completely clean of

tissue in routine preparations.

Disadvantages

Due to the simple, quick-staining technique,

the radula cannot be stained and destained to

obtain the perfect density of staining. It also

cannot undergo multiple stainings. However,

this type of treatment is usually given to large

radulae and generally cannot be accomplished

with minute ones.

The use of CMC for large radulae has been

found to be undesirable because of the large

distance required between the cover slip and the

slide. Initially, such a mount seems normal, but

with time large bubbles form under the cover

slip. The ring of sealant around the cover slip

usually separates, allowing moisture from the

CMC to evaporate, which in turn allows the

CMC to contract, pulling air bubbles in from the

margins of the mount. Medium-sized, easily

handled radulae may be mounted with CMC, but

because of their size they may retain too much

fluid to be placed directly into the mountant

following removal from NaOH; a water wash

may be required between these two steps.

Acknowledgments

The manuscript was reviewed by Drs. Joseph

Rosewater, Richard S. Houbrick and Robert W.

Virnstein. Their criticism is very much ap-

preciated.

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 65

BIBLIOGRAPHY

Aboulafin, A. 1970. [preparation of radulae for microscopic

observation and permanent mounting.] (in Yiddish)

Argamon: Jour. Israel Malacolog. Soc. l(2):62-68.

Baas Becking, L. G. M. and J. C. Chamberlain. 1925. A note

on the refractive index of chitin. Proc. Soc. Exp. Biol. &

Med. 22:256.

Basch. P. F. 1961. A simple method for preparing radulae.

Turtox news 39(1):46.

Beckett. D. C. and P. A. Lewis. 1982. An efficient procedure

for slide mounting of larval chironomids. Trans. Am.

Micros. Soc. 101(l):96-99.

Beecher, C. E. 1888. A method of preparing, for microscopi-

cal study, the radulae of small species of Gasteropoda.

Jour. N Y. Microscop. Soc. 3:7-11.

Binney, W. G. 1885. A manual of American Land Shells.

Washington; Government Printing Office; 528 pp.

Bowell, E. W. 1915. On the mounting of radulae for micro-

scopic examination. Proc. Malac. Soc. London 11(5):

272-274; pi. 7.

1924a. Radulae of Mollusca. J. Quekett Micro-

scop. Club Series 2, 15, 57-64.

. 1924b. The mounting of radulae for photomiero-

mounts of radulae. Basteria 14(l-2):28-32; 14(3-4):33-43.

1950b. Verborgen schoonheid. De Levende

graphy. J. Roy. Microscop. Soc. 44:292-294.

1928. A Review, The microscopy of radulae. J.

Roy. Microscop. Soc. series 48 (part 2):161-177; pis. 1-4.

Davis, G. M. 1964. A rapid method for mounting larval tre-

matodes. Turtox News 42(1):40-41.

Environmental Protection Agency. 1980. Macroinverte-

brate mounting media. E. P. A. Newsletter, Quality

Assurance 3(3): 1 pg.

Fritchman, H. K., II. 1960. Preparation of radulae. Veliger

3(2):52-53.

Gascoigne, T. 1975. Methods of mounting Sacoglossan radu-

lae. Microscopy 32:512-516.

Glaugher, D. 1965. Preparation of the radula. Conch. Soc.

Gr. Brit. & Ireland; Papers for students No. 5.

Hickman, C. S. 1977. Integration of Electron scan and light

imagery in study of molluscan radulae. Veliger 20(l):l-8.

Knudsen, J. W. 1966. Biological techniques. Harper & Row,

New York: xi + 525 pp; illust.

Lindberg, D. R. 1977. Artifacts incurred by the treatment of

acmaeid radulae with alkalies. Veliger 19(4):453-454.

Marson, J. E. 1971. Making mounts in glycerine jelly. N.B.S.

Booklet No. 2, Northern Biological Supplies, Ipswich.

Meeuse, A. D. J. 1949a. De radula van slakken als micro-

scopish object. Microwereld 4:677-684.

1949b. Over de radula's van Mollusca. Corr.bl.

Ned. Malac. Ver.. No. 34:274-277.

1950. Rapid methods for obtaining permanent

Natuur 53:9-15.

Michelson, E. H. 1960. A rapid method for preparing mounts

of snail genitalia. The Nautilus 74(l):32-33.

Morris. T. E. and C. S. Hickman. 1981. A method for artifi-

cially protracting gastropod radulae and a new model of

radula function. Veliger 24(2):85-90.

Morrison, J. P. E. 1951. How I prepare radulae. News

Bulletin and Annual Report. American Malacological

Union for 1950: 16-17. [Title inside front cover.]

Pantin, C. F. A. and T. Rogers. 1925. An amphoteric sub-

stance in the radula of the whelk (Buccinum undatum).

Nature 115:639-640.

Ploeger, S. and A. S. H. Breure. 1977. A rapid procedure for

preparation of radulae for routine research with the scan-

ning electron microscope. Basteria 41:47-52.

Radwin, G. E. 1969. Technique for extraction and mounting

of gastropod radulae. Veliger 12(1):143-144.

Risso-Dominguez, C. J. 1961. The use of alkylene polyamines

to isolate radulae. I. Reactions between effectiveness and

chemical structure. Stain Technology 36(3):151-157.

1964. The use of alkylene polyamines to isolate

radulae. II. Practice and technique. Stain Technology

39:195-204.

Rogers, T. H. 1924. Electrical methods of staining the

radulae of Mollusca. J. Roy. Microscop. Soc. 44:295-298.

Runham, N. W. and P. R. Thornton. 1967. Mechanical wear

of the gastropod radula: a scanning electron microscope

study. J. Zooi. London 153:445-452.

Schooley. C, C. S. Hickman and W. C. Lane. 1982. Com-

puter graphic analysis of stereo micrographs as a tax-

onomic tool. Veliger 24(3):205-207, 1 pi.

Solem, A. 1972. Malacological applications of scanning elec-

tron microscopy. II. Radular structure and functioning.

Veliger 14:327-336.

Solem, A. and J. L. van Goethem. 1974. Scanning electron

microscope and optical microscope observations on

urocyclid land snail radulae (Mollusca, Pulmonata,

Urocyclidae). Bull. Inst. roy. Sci. nat. Belg.. Biologic

50(70): 1-9.

Thompson, T. E. and H. E. Hinton. 1968. Stereoscan micro-

scope observations on opisthobranch radulae and shell

sculpture. Bijdr. Dierk. 38:91-92.

Turner, R. D. 1960. Mounting minute radulae. The Nautilus

73(4):135-137.

Verdcourt, B. 1946. An introduction to the study of radulae.

The Microscope (London) 6:35-39.

1948. The staining of radulae. Stain Technology

23(3):145-149.

66 THE NAUTILUS

April 29, 1985

Vol. 99 (2-3)

SEDIMENT PREFERENCE OF THE FRESHWATER

ASIATIC CLAM, CORBICULA FLUMINEA

Scott E. Belanger, Jerry L. Farris, Donald S. Cherry, and John Cairns, Jr.

Department of Biology and

University Center for Environmental Studies

Virginia Polytechnic Institute and State University

Blacksburg, VA 24061

ABSTRACT

Corbicula fluminea, the Asiatic clam, occurs in well-oxygenated lotic systems in

sediments of various compositions. This study reports on rigorously controlled

studies o/Corbicula preferences of fine sand (predominantly between 0.25-0. 7 mm

particle size), organically enriched fine sand (predominantly between 0.25-0.7

mm particle size), coarse sand (predominantly 2.5-4.5 mm particle size), and no

substrate in artificial streams in laboratory and field-laboratory settings using a

paired choice design. In both the laboratory and field- laboratory, Corbicula

preferred the sediments in the decreasing order of fine sand - organically enriched

fine sand - coarse sand - no substrate. The density o/Corbicula at an industrially

uninfluenced site in the New River was significantly greater in fine sand (452

clams/m2 with 70% of the sediment in the 0.35-0.60 mm particle size range) than

coarse sand/gravel (177 clams/m2 with 90% of the sediment in the 4.5-38.0 mm

particle size range). The invasion of Corbicula into new habitats has been

facilitated by the ability of the clam to utilize a wide variety of substrates, from

fine sand to gravel. This study suggests that rivers with fine, well-oxygenated sand

substrates would be optimal for establishment of Corbicula populations in newly

colonized sites.

Corbicula fluminea, the introduced Asiatic

clam, is a species that flourishes in well-oxygen-

ated lotic systems. In these habitats, C. flu-

minea inhabits nearly all sediment types to

varying degrees (Home and Mcintosh, 1979;

Rodgers et al., 1979). Elimination or reduction

of Corbicula. populations has been recorded in

association with sediments of high organic and

low oxygen content (Aldridge and McMahon,

1978; McMahon, 1979; Eng, 1979). Respiration

was shown by Dudgeon (1980) to be correlated

inversely with mean particle size and perhaps

related to increased metabolic demands of clams

in fine substrates.

Densities of Corbicula in North America are

greatest in well-aerated sand or sand-gravel

mixtures (McMahon, 1983). Corbicula became

established in the New River in southwestern

Virginia around 1977 (Rodgers et al, 1977).

Graney et al. (1980) determined that Corbicula

showed little discernible substrate preference

within and outside a thermal discharge at the

Glen Lyn Power Plant, Virginia, achieving max-

imal densities of 11,522 clams/m2 in the dis-

charge (sand to sand-gravel) and 2,286/m2 in

uninfluenced regions of the river at the plant in

fine sand to sand sediments. Upstream of the

Glen Lyn Plant, establishment of Corbicula has

required more time (e.g., ~3 years). Cherry et

al. (in press) have documented clam densities of

3, 397-23, 689/m2 at an industrial pumphouse

station (Celanese Fibers Corporation, Narrows,

Virginia) 9.9 km upstream of the Glen Lyn

Plant. This site is thermally uninfluenced and is

characterized by well-oxygenated sediment with

68% of the particles in the size range of 0.25-

0.7 mm.

Thus far, conventional wisdom of Corbicula

distributional ecology has been that clams pre-

fer coarse sand (1.5-2.5 mm) or mixed sand/

gravel (2.5-60 mm) based upon field sampling

results. A combination of rigorously controlled

preference studies in the laboratory, field-

laboratory, or in field validation experiments

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 67

has not been attempted. Objectives of the

research herein were to determine the prefer-

ence of adult Corbicula for distinct sediment

size classes (0.2-40 mm) using a paired choice

experimental design. Preference trials were

performed in a formal laboratory artificial

stream and field-laboratory setting and subse-

quently validated by field sampling in the New

River.

Materials and Methods

Laboratory Preference Study

Preference trials were conducted in February,

March, and April 1984 at the University Center

for Environmental Studies Ecosystem Simula-

tion Laboratory (ESL) at Virginia Polytechnic

Institute and State University (Va Tech). Sedi-

ment preference chambers were constructed

using plexiglass (17.5x17.5x1.5 cm). Three

chambers were placed in each of six artificial

streams (Fig. 1; Farris et al., in review). The cir-

cular artificial streams have a 20-1 capacity and

are circulated by a gear-driven paddle wheel

system to provide a uniform current flow similar

to the river environment. Each stream received

dechlorinated Blacksburg town tap water

(water quality summarized in Table 1) at a flow

rate of 300-400 ml/min which resulted in 21.6-

27.0 turnovers per day. Water temperatures

ranged from 10 to 17°C. Adult Asiatic clams

(12-17 mm shell length) were obtained from the

New River and acclimated to laboratory condi-

tions for 5-7 days. Fine sand (72% between

0.25-0.7 mm), organically enriched fine sand

(72% between 0.25-0.7 mm), and coarse sand

(83% between 2.5-9.0 mm) sediment types were

chosen for testing in these experiments based

on their suspected relevance to Corbicula in the

New River (Graney et al, 1980). Fine sand was

obtained in the New River near the Celanese

Fibers Corporation and was sterilized prior to

use by drying at 90°C for 24 hr and 500°C for 24

hr. Organically enriched fine sand was prepared

by freeze drying Elodea sp. and Nasturtium sp.

(water cress) in liquid nitrogen, crushing the

frozen material, and mixing the organic matter

50:50 by volume (15:85 by weight) with sterilized

fine sand. Coarse sand was obtained from a

small fast flowing stream (Sinking Creek) near

the Va Tech campus. Gravel was obtained from

an aquarium supplier in Blacksburg. No

substrate consisted of stacked 0.635 cm plexi-

glass plates.

For each preference trial, two substrates were

placed side-by- side with a sharp, linear demarca-

tion between them in each preference chamber

(Fig. 1). Five adult clams were placed umbo

down along the line of demarcation. Three repli-

cates were used for each pair of sediments com-

pared during the experiment: no substrate vs

fine sand, no substrate vs organically enriched

fine sand (hereafter referred to as "organic" in

tables), no substrate vs coarse sand, fine sand vs

organically enriched fine sand, fine sand vs

coarse sand, and organically enriched fine sand

vs coarse sand. Positions of the five Corbicula

were traced for 7 days after preliminary prefer-

ence trials of 3 weeks suggested this interval

TABLE 1. Water quality parameters for the laboratory experiments (ESL), field-

laboratory experiments (Glen Lyn), and field survey. The range is below the mean for each

parameter in parentheses. Sample sizes are n = 2 for the ESL streams, river- fed streams at

Glen Lyn, and for the field survey.

68 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

FIG. 1. Artificial stream system and plexiglass sediment

preference chambers (P) used in laboratory substrate

preference experiments at the Ecosystem Simulation

Laboratory. Inflow water (arrow) is circulated bj a paddle

wheel (W) attached to a single speed gear motor.

was more than sufficient for clams to attain a

final, permanent position in the preference

chamber.

Field-Laboratory Preference Study

Sediment preference experiments were con-

ducted in June, August, and October 1984 at a

field-laboratory located at the Glen Lyn Power

Plant adjacent to the New River. New River

water was delivered from submerged pumps to

4.6-m fish hatchery troughs at the rate of 4 1/min

(see Clark et al, 1980). The depth of the water

was maintained at 12-14 cm, resulting in 19.8-

23.0 turnovers per day. Water temperatures

ranged from 11 to 20° C. Plexiglass sediment

preference chambers described earlier were

placed on top of 8-cm platforms to minimize the

potential of river silt settling onto the chambers.

The experimental protocol used in the field-

laboratory study was identical to the formal

ESL study except all chambers and sediment

preference trials were placed in one stream. The

clams used for these studies were collected from

the Celanese Fibers Corporation pumphouse in

April and May 1984 and maintained in a hatch-

ery trough at the Glen Lyn Plant. New River

water quality for these experiments is sum-

marized in Table 1.

Field Sampling

Estimates of the density of Corbicula were

made on September 9 and December 18, 1984,

in the New River at McCoy, Virginia. This site

was chosen because: (1) it receives no industrial

influence and, therefore, represents a natural

Corbicula population in the New River, (2) the

sampling region has several distinct substrate

types relative to particle size in close proximity

under nearly equal current regimes, and (3) ac-

cessibility for sampling a 0.3-m water depth was

advantageous for sampling gear. Density esti-

mates were derived for two substrate types, fine

sand and sand/gravel, by removing triplicate

samples from each area with a Surber sampler

(0.1 m2 sampling area). Each sediment-clam

sample was placed individually in buckets and

returned to the laboratory for analysis. Clams

were handpicked from each sample. Sediment

was dried and sieved to determine sediment

composition by weight using a Metier PC-440

electronic balance (accuracy, ±0.0005 g). Adult

(>8.0 mm shell length) and juvenile (~2. 5-8.0

mm shell length) clams were measured for shell

length by vernier calipers (accuracy, ±0.05 mm).

Estimates of "larval" (veliger) density in each

sample were made by analyzing the sediment

fractions that were <2.5 mm from each

replicate.

Statistical Treatment of Data

Preference experiments were analyzed by

one-way analysis of variance (ANOVA) (Steel

and Torrie, 1960) at each observation period and

for each sediment pairing. For each pair of

sediments, three possible outcomes were com-

pared: (1) clams would reside in sediment A, (2)

clams would reside in sediment B, or (3) clams

would remain in the region of the demarcation

between sediment A and sediment B. If a

significant difference existed by the ANOVA

F-test (a = 0.05), Duncan's Multiple Range Test

was performed to determine which group(s)

were significantly different (Steel and Torrie,

1960). Results of Corbicula densities observed in

the field in coarse and fine sediments were

analyzed by the student's t-test.

Results

Laboratory Preference Study

Corbicula were found to prefer any substrate

(fine sand, organically enriched fine sand, or

coarse sand) over no substrate at all (Table 2).

Clams were observed to move rapidly into sedi-

ments. After 1 hr, 70-80% of the clams were

buried in the sediments offered. By the third

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 69

TABLE 2. Analyses of variance for Corbicula sediment preference of fine sand versus no substrate,

organically enriched fine sand versus no substrate, and coarse sand versus no substrate conducted at

the Ecosystem Simulation Laboratory and Glen Lyn field laboratory. Means with the same letter are

not significantly different (o = 0.05) using Duncan's Multiple Range Test.

'All clams resided in the substrate from Day 3 to Day 7. Analyses of variance are not quoted since the

data are unsuitable for this statistical method.

2Uncommitted clams were designated as those that did not move from the line of demarcation be-

tween sediments.

day, 100% of the clams were buried in all sedi-

ments, and none remained exposed (Table 2).

Clams consistently preferred fine sand or or-

ganically enriched fine sand when coarse sand

was the alternative choice (Table 3). The choice

of fine sands was significant by Day 3 (Table 3),

although, for fine sand alone, the choice was

made sooner (on Day 1; Table 3).

When clams were offered the choice of organi-

cally enriched fine sand vs fine sand, the prefer-

ence pattern was less distinct than for either of

these sediments vs no substrate or coarse sand

(Table 3). Ultimately, fine sand was significantly

preferred over organically enriched fine sand

(Days 6 and 7; Table 3).

Field-Laboratory Preference Study

Results of these preference trials were similar

to experiments conducted at the ESL. Any

substrate (e.g., fine sand, organically enriched

fine sand, and coarse sand) was significantly

preferred over no substrate at all (Table 4). By

Day 3, all clams were buried in fine sand, organi-

cally enriched fine sand, and coarse sand when

no substrate was the alternative (Table 4).

Clams did not prefer coarse sand when offered

fine or organically enriched fine sand; however,

fine sand was significantly preferred sooner

(Day 1; Table 4) than organically enriched fine

sand (Day 3; Table 4). By Day 7, 78% of the

clams resided in fine sand when coarse sand was

the alternative, and 71% resided in organically

enriched fine sand when coarse sand was the

alternative (Table 4). Preference trials of fine vs

organically enriched fine sand showed clams

preferred fine sand. By Day 5, 60% of the clams

resided in fine sand substrate (Table 4).

Field Sampling

The density of Corbicula was two to three

times greater in fine sand (75% of the sediment

was in the 0.35-0.60 mm size range) than coarse

70 THE NAUTILUS April 29, 1985 Vol. 99(2-3)

TABLE 3. Analyses of variance and percent residence for Corbicula sediment preference experiments at the Ecosystem

Simulation Laboratory. Means with the same letter are not significantly different (a = 0.05) using Duncan's Multiple Range

Test.

F (and in parentheses, p-values) were 0.44 (0.6464); 2.71 (0.0866); 11.71 (0.0009); 19.50 (0.001);

43.37 (0.0001) for time 1 hr through Day 7.

F (and in parentheses, p-values) were 1.67 (0.2085); 28.50 (0.0001); 6.15 (0.0112); 29.67 (0.0001);

10.25 (0.0016) for time 1 hr through Day 7.

F (and in parentheses, p-values) were 1.98 (0.1605); 11.90 (0.0030); 0.48 (0.6245); 9.61 (0.0021);

13.93 (0.0004) for time 1 hr through Day 7.

TABLE 4. Analyses of variance and percent residence for Corbicula sediment preference experiments at Glen Lyn. Means

with the same letter are not' significantly different (a = 0.05) using Duncan's Multiple Range Test.

F (and in parentheses, p-values) were 3.24 (0.050); 2.78 (0.0825); 6.68 (0.0049); 25.20 (0.0001);

60.78 (0.0001) for time 1 hr through Day 7.

2F (and in parentheses, p-values) were 36.91 (0.0001); 24.4 (0.0001); 32.69 (0.0001); 19.45 (0.0001);

29.10 (0.0001) for time 1 hr through Day 7.

F (and in parentheses, p-values) were 5.15 (0.0138); 2.57 (0.0973); 5.59 (0.0102); 46.91 (0.0001);

18.44 (0.0001) for time 1 hr through Day 7.

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 71

sand/gravel substrate (90% of the sediment was

in the 4.50-36.00 mm size range) in the New

River. Sediment composition of the December

18 samples is summarized in Figure 2. The den-

sities of adult and juvenile Corbicula were ap-

proximately the same for both samples in the

respective sediments (Table 5). After combining

the results of both September 9 and December

18 samples, a t-test indicated that the densities

of the clams were significantly greater in the

finer sand substrate than in coarse sand/gravel.

These results are consistent and supportive of

the laboratory and field-laboratory preference

experiments.

Discussion

Sediment preferences of Corbicula were con-

sistent in both laboratory and field-laboratory

experiments. Although some temporal differ-

ences existed for some comparisons, relative to

where the experiment was performed (e.g., fine

sand vs coarse sand, and fine sand vs organi-

cally enriched sand), the preferences were ulti-

mately identical (i.e., fine sand was preferred

i

o

>-

CO

o

5

o

o

z

LU

O

DC

LU

a.

z

<

30

20

ja

.H

-S

JS

am

Coarse Sand /Gravel

Fine

JOi

L

<0.10 0.11 0.26-

0.25 0.35

0 36

0.50

0.51

0.60

0 61

0.70

071-

1.50

151-

2.50

2.51

4 50

4.51- 9 51 18 01

9.50 18.00 3600

PARTICLE SIZE |mm|

FIG. 2. Mean percent composition by weight of coarse sand/gravel samples and fine sand samples

from the New River taken by Surber sampling for Corbicula densities.

TABLE 5. Densities of larval (^1 mm), juvenile (1.0 to 8.0 mm) and adult Corbicula (>8.0 mm) within the New River at

McCoy, Virginia.

Collection

Date

Sediment

Type

Larval

Density t-test

( individuals/m2 ) {p-value)

Juvenile/Adult

Density

(individuals/m2

t-test Shell length

(p-value) (Means±SD)

t-test

(p-value)

72 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

for the aforementioned comparisons). Thus, it

was possible to rank the observed experimental-

ly identified preferences to predict the sites/

substrates of varying densities of clams located

in the field. The preferences observed in these

studies were in the following descending order:

fine sand - organically enriched fine sand -

coarse sand - no substrate. The field sampling,

which found clams to be significantly denser in

the fine sand than coarse sand/gravel under

similar environmental conditions of current,

temperature, light, and season, corroborated

our predictions in this study.

The importance of sediment to population

dynamics and success of Corbicula invasion has

been previously emphasized by several investi-

gators. Eng(1979) discussed the use of incrusta-

ceans along the Delta- Mendota concrete canal

by Corbicula as a nursery zone and refuge for

larvae and small juveniles. Sickel and Burbank

(1974) investigated preferences of newly re-

leased juveniles for substrates and found coarse

sand was preferred over mud (potentially

oxygen-limiting) or bare concrete (ecologically

barren surface). McMahon (1983) suggested that

flourishing Corbicula populations in streams

that are canalized may optimize the environ-

ment for this species by eliminating the reduc-

ing environments of mud and silt under fast

flowing conditions. The importance of thermal

inputs from power plants and other industrial

installations has been documented previously by

several investigators (Rodgers et al., 1977;

McMahon, 1977; Scott- Wasilk et al, 1983).

Graney et al. (1980) surveyed Corbicula popula-

tions at the Glen Lyn Power Plant in thermally

influenced and uninfluenced stations with vari-

ous substrate compositions and concluded that

thermal discharges had a greater influence upon

clam survivorship and density than substrate

composition. It is important to note that ther-

mal effluents allow clams to sustain reproducing

populations over the winter where they would

otherwise not occur (Graney et al., 1980; Scott-

Wasilk et al., 1983; McMahon, 1982).

Corbicula has continued to invade new habi-

tats in North America and is now found in near-

ly every state in the continental United States

(McMahon, 1982). The ability of Corbicula to

utilize a wide variety of substrates, from fine

sand to gravel (which Corbicula finds inhabit-

able), has enhanced its success. However, this

study suggests that rivers with fine, well oxy-

genated sand substrates would be optimal for

establishment of Corbicula populations in newly

colonized sites.

LITERATURE CITED

Aldridge, D. W. and R. F. McMahon. 1978. Growth, fecund-

ity, and bioenergetics in a natural population of the fresh-

water clam, Corbicula manileyisis Phillippi, from North

Central Texas. Jour. Mollusc. Studies 44:49-70.

Cherry, D. S., R. L. Roy, R. A. Lechleitner, P. A. Dunhardt,

G. T. Peters and J. Cairns, Jr. In Press. Corbicula invasion

in the New River: fouling and control measures at the

Celco Plant, Virginia. In Proceedings of the 1983 Second

International Corbicula Symposium. Little Rock,

Arkansas.

Clark, J. R., J. H. Rodgers, Jr., K. L. Dickson and J. Cairns,

Jr. 1980. Using artificial streams to evaluate perturbation

effects on aufwuchs structure and function. Water

Resourc. Bull 16:100-104.

Dudgeon, D. 1980. A comparative study of the Corbiculidae

of Southern China. In B. Morton (editor) The Malaco-

fauna of Hong Kong and Southern China. Hong Kong

University Press, Hong Kong. p. 37-60.

Eng, L. L. 1979. Population dynamics of the Asiatic clam,

Corbicula fluminea (Miiller), in the concrete-lined Delta-

Mendota canal of central California. In J. C. Britton

(editor) Proceedings of the First International Corbicula

Symposium. Texas Christian University, Fort Worth.

Texas, p. 39-68.

Graney, R. L., D. S. Cherry, J. H. Rodgers, Jr. and J. Cairns,

Jr. 1980. The influence of thermal discharges and sub-

strate composition on the population structure and distri-

bution of the Asiatic clam, Corbicula fluminea, in the New

River, Virginia. The Nautilus 94:130-135.

Home, F. R. and S. Mcintosh. 1979. Factors influencing

distribution of mussels in the Blanco River of Central

Texas. The Nautilus 93:119-133.

McMahon, R. F. 1977. Shell size-frequency distribution of

Corbicula manilensis Philippi from a clam-foaled steam

condenser. The Nautilus 91:54-59.

1979. Response to temperature and hypoxia in

the oxygen consumption of the introduced Asiatic fresh-

water clam Corbicula fluminea (Muller). Camp. Biochem.

Physiol. 63A:383-388.

1982. The occurrence and spread of the intro-

duced Asiatic freshwater clam, Corbicula fluminea

(Muller), in North America: 1924-1982. The Nautilus

96:134-141.

1983. Ecology of the invasive pest bivalve

Corbicula. In W. D. Russel-Hunter (editor) Tin Mollusca:

Ecology. Vol. 6. Academic Press, Inc., New York.

p. 505-562.

Rodgers. J. H.. Jr.. D. S. Cherry, J. R. Clark. K. L. Dickson

and J. Cairns, Jr. 1977. The invasion of Asiatic clam,

Corbicula manilensis. in the New River. Virginia Tin

Nautilus 91:43-46.

Rodgers, J. H.. Jr., D. S. Cherry, K. L. Dickson and J.

Cairns, Jr. 1979. Invasion, population dynamics and ele-

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 73

mental accumulation of Corbicula fluminea in the New

River at Glen Lyn, Virginia. In J. C. Britton (editor)

Proceedings of the First International Corbicula Sympo-

sium. Texas Christian University, Fort Worth, Texas,

pp. 99-110.

Scott-Wasilk, J., G. G. Downing and J. S. Leitzow. 1983.

Occurrence of the Asiatic clam Corbicula fluminea in the

Maumee River and Western Lake Erie. Journ. Great

Lakes Res. 9:9-13.

Sickel, J. B. and W. D. Burbank. 1974. Bottom substratum

preference of Corbicula manilensis (Pelecypoda) in the

Altamoha River, Georgia. Assoc. Southeastern Biol. Bull.

21:84.

Steel, R. G. D. and J. H. Torrie. 1960. Principles and Pro-

cedures of Statistics with Special References to the

Biological Sciences. McGraw-Hill, New York. 481 p.

A WEST INDIAN COLUMBELLID NEW TO THE

GENUS STEIRONEPION

C. John Finlay

1024 Daytona Dr. NE

Palm Bay, FL 32905

ABSTRACT

In 1850 C. B. Adams described Pleurotoma maculata from Jamaica. Subse-

quent beach specimens from Varadero Beach, Cuba, and the Bahamas, as well as

examples from dredged sand at Marianao, Havana, Cuba (described as Turri-

jaumelia jaumei Sarasila, 1975), further extend, the known range. A morphological

assessment would suggest that the species be placed in the columbellid genus

Steironepion, thus adding a third species to that genus from the Caribbean

marine basin, and making Turrijaumelia a subjective synonym of Steironepion.

In "Poeyana", published under the auspices of

the Institute of Zoology, Cuban Academy of

Sciences, Havana, Cuba, Dr. Hortensia Sarasiia

described a new turrid gastropod, erecting the

new genus and species Turrijaumelia jaumei.

Although the type specimen of Pleurotoma

maculata Adams, 1850, figured by Clench and

Turner, is a worn specimen, there seems little

doubt that T. jaumei should be synonomized

with that taxon. None of the Cuban or Baha-

maian specimens were live-taken.

Perusal of George Radwin's comprehensive

treatment of the family Columbellidae in the

western Atlantic, would suggest adding this

species to the genus Steironepion which now

contains the Caribbean species S. minor (C. B.

Adams, 1845) and S. moniliferum Sowerby,

1844). Placement of this columbellid in the Tur-

ridae by Adams and Sarasiia may have resulted

in their considering the rather swollen anal

sinus as a turrid notch.

Since C. B. Adams' description of this species

is very brief, it is deemed desirable to translate

and reproduce below Dr. Sarasiia's detailed

description of this very attractive little shell.

Turrijaumelia, new genus

Description: Shells small, slender, not fragile

but delicate. Large nuclear whorls, smooth and

bulbous, the post nuclear whorls are character-

ized by angular perimeters and well defined

sutures. Sculpture reticulated, formed by thin

axial ribs, crossed by smooth spiral cords, form-

ing sharp rib projections on the lower half of the

whorls. The spaces between the reticulated

sculpture reveal numerous microscopic axial

threads. Aperture narrow, sigmoidal, with the

anal channel somewhat enlarged. Outer lip with

slight stromboid notch, showing interior liration

and the anterior canal recurved backwards and

to the right.

Genotype - Turrijaumelia jaumei, new species

Discussion: Among the many genera of the

Turridae, we have not been able to find one fit-

ting our lot; the bulbous and smooth nuclear

whorls, the angular periphery of the post

nuclear whorls, the smooth spiral cords, the rib

projections and the peculiar microscopic axial

threads in the reticulated spaces, give us what

74 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

we believe to be sufficient characteristics to

establish the new genus Turrijaumelia.

Turrijaumelia jaumei, new species

Description: Shell small, elongated and

graceful, of delicate and vitrious appearance;

nuclear whorls two, large bulbous and smooth,

followed by 4-4.25 post-nuclear whorls, well

defined suture and angular periphery. The last

whorl narrows and forms the siphon canal com-

pleting the graceful appearance of the species.

Sculpture consisting of marked narrow ribs,

more or less 12 on the last whorl, higher on the

lower half of the whorls and more slender at the

base of the shell, crossed by smooth spiral cords,

well separated. At the top half of the whorls,

which are strongly sloped, there are 3 or 4 spiral

cords of the same width, separated by a space

more or less the same width as the width of

these cords. The spiral cords on the lower half of

the whorls are wider and more separated from

one another, the first extends from the middle

line of each whorl, and these in turn form the

sharp rib projections which point upwards;

three of these spiral cords are observed on the

last whorl. At the base of the last whorl are two

spiral cords, the first of which may have slender

projections, on the second these may appear in-

stead as small nodules. On the siphon canal are

two spiral cords of small nodules, followed by

three narrow cordlets.

In the translucent spaces of the reticulated

area, which on the lower half of the whorls, are

large and rectangular, are microscopic axial

threads, straight and parallel, separated from

one another by spaces more or less the same as

their width; these axial threads reach the sides

and surface of the ribs, and at the point appear

slightly curved. On the siphon canal the spiral

sculpture is crossed by microscopic axial lines.

The outer lip of the aperture reveals four den-

ticulations on the inside border formed by the

termination of the lirations, the two upper ones

being clearly visible. The general color of the

shell is white, a few brown spots are observed on

the upper part of the spiral cords where the

whorls slope downward; the base of the last

whorl may be yellowish, and a touch of brown

may appear on the last rib. On the nuclear

whorls, at the beginning of the suture, there is

generally a brownish spot.

The measurements given for the width of the

shells, are without consideration to the

sculptural projections.

Width Width

Length (greatest) (narrowest)

Holotype 4 mm 1.75 mm 1.70 mm Marianao, Habana

Paratype 4 mm 1.60 mm 1.50 mm Marianao, Habana

Paratype 4.1 mm 1.50 mm 1.40 mm Marianao, Habana

The type shells form part of a lot of 19

specimens, dredged from sand at a depth of ap-

proximately 20 metres, were taken offshore at

Marianao, Habana, and collected by Sr. Primi-

tivo Borro. Another three specimens were found

by the author in sand from the same location.

Type catalog No. 36 (holotype) and 37 and 38

(paratypes.)

Steironepion maculatum (C. B. Adams, 1850)

(Figs. 1. 2)

Synonomy -

1850 Pleurotoma macuiata C. B. Adams. 1850, Contribu-

tions to Conchology, No. 4, p. 62 (Jamaica); 1950 Clench

and Turner, Occasional Papers on Mollusks, vol. 1, No.

15, p. 305, pi. 29, fig. 3 (holotype)

1887 Pleurotoma (DriUia) maculata Verkruzen. Paetel,

Catalog der Conchylien-Sammlung von Fr Paetel. vol. 1.

p. 56 (Jamaica), [listing only].

1975 Turrijaumelia jaumei Sarasua, Poeyana (Havana), No.

140, pp. 12-15, (20 metres, off Marianao, Habana, Cuba).

Records -BAHAMAS: West Beach, Staniel

Cay, Exhumas, Dieter Cosman collector, 1966.

CUBA: Varadero Beach, North coast of Cuba

(drift), C. John Finlay collector, 1952; Marianao,

Habana, Primitivo Borro and Hortensia

Sarasua, from sand dredged in 20 metres.

JAMAICA: C. B. Adams, 1850; Paetel, 1887.

Genus Steironepion Pilsbry and Lowe, 1932

Synonomy -

1932 Steironepion Pilsbry and Lowe, Proc. Acad. Sat. See

Philadelphia, vol. 84, p. 57 (type by original designation:

Mangelia melanosticta Pilsbry and Lowe, 1932).

1943 Psarostola Render, Proc U. S. Nat. Mus., vol. 93, No.

3161, p. 198 (type by original designation: Columbella

monilifera Sowerby, 1844).

1975 Turrijaumelia Sarasua, Poeyana (Havana), No. 140,

pp. 12-15, (type by monotypy: T. jaume) Sarasua. 1975)

This interesting group of small columbellids

with a reticulated or beaded sculpture and a

strong anal notch has been placed in the turrids

by many authors until Rehder (1943), Keen

(1971) and Radwin (1977) showed its columbellid

affinities both in shell and radular characters.

Curiously, Sowerby (1844), Duclos (1848 and

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 75

FIGS. 1, 2. Steironepion maeulatum (C. B. Adams, 1850).

Beach drift, Varadero Beach, north coast of Cuba, 1952, 4.5

mm, C. J. Finlay collector.

Try on (1883) also placed Steironepion rnonili-

ferum (Sowerby, 1844) in the Columbellidae.

Radwin (1977) removed Steironepion from the

genus Nassarina and considered it a full genus,

a view in which I concur.

Acknowledgments

Thanks go to Dr. R. Tucker Abbott for his en-

couragement in writing this paper and for his

critical reading of the manuscript. I am also in-

debted to Mrs. Virginia 0. Maes for reviewing a

preliminary outline of the paper. To Mr. Paul

Mikkelsen many thanks are due for the fine

photographs of the Varadero Beach specimens.

LITERATURE CITED

Clench, W. J. and Turner. R. D., 1950. The Western Atlantic

Marine Mollusks described by C. B. Adams. Occasional

Papers on Mollusks, Vol. 1, June 26, 1950.

Sarasua, H., 1975. New Genera, Subgenera and Species of

Neogastropod Marine Mollusks, Poeyana. Academy of

Sciences, Habana, Cuba. No. 140, pp. 12-15, January 17.

1975.

Radwin, G. E., 1977. The Family Columbellidae in the West-

ern Atlantic, Part Ha. The Veliger, Vol. 20, No. 2,

pp. 119-133.

ACTIVITY PATTERNS AND HOMING IN TWO INTERTIDAL

LIMPETS, JORDAN GULF OF AQABA

Neil C. Hulings

Marine Science Station

P.O. Box 570

Aqaba, Jordan

ABSTRACT

The foraging and homing behavior of Cellana radiata (Born) and Siphonaria

laciniosa (Linne) occurring in the rocky intertidal zone has been determined. C.

radiata, a prosobranch, forages when submerged during day and night, is a tem-

porary homer and migrates up and down with changes in sea level. S. laciniosa, a

pulmonale, forages when submerged but only after sunset and is a rigid homer.

Homing behavior in relation to desiccation and density dispersion are discussed.

Migration, intra- and interspecific competition are also discussed.

Activity patterns, including foraging and

homing of many prosobranch and pulmonale

limpets, have been investigated for many years.

The patterns, especially foraging or feeding ex-

cursions, have been found to be quite variable as

to when and under what conditions they occur.

Homing has also been found to be variable and

various reasons have been proposed for such

76 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

behavior including reduction of desiccation, bet-

ter utilization of resources, especially food and

protection from predators (Underwood, 1979;

Branch, 1981; Garrity and Levings, 1983 and in-

cluded references).

There are only two limpets found in the rocky

intertidal zone along the coast of Jordan, the

patellid Cellana radiata (Born, 1778) (alias C.

rota (Gmelin, 1791)) and the pulmonate Sipho-

naria laciniosa Linne, 1758 (alias S. kurra-

cheensis Reeve, 1856). C. radiata is the larger of

the two species, reaching lengths of up to 48

mm, whereas S. laciniosa rarely exceeds 20

mm. Both species occur in the midlittoral zone

of Stephenson and Stephenson (1949) within

which Safriel and Lipkin (1964) designated a

higher chthamalid zone and a lower Tetraclita

zone. C. radiata has a wide vertical distribution,

ranging from above the chthamalid zone to

below the Tetraclita zone and occurs on vertical

to horizontal surfaces of boulders, pebbles and

various types of slab substrata. S. laciniosa, in

contrast, is mostly restricted to near the chtha-

malid zone (within the range of C radiata) and

occurs more commonly on horizontal, soft, cal-

careous substrata rather than on hard sub-

strata. Both limpets are grazers, feeding on

microalgae.

Prior to the present report, nothing was

known of the foraging and homing behavior of

Cellana radiata and Siphonaria laciniosa in the

Red Sea. Voucher specimens of both species are

on deposit in the U.S. National Museum of

Natural History and in the reference collection

of the Marine Science Station in Aqaba, Jordan.

The Rocky Intertidal

The rocky intertidal zone along the coast of

Jordan is quite variable, ranging from granitic

boulders to multicolored pebble beaches to low

profile slab or platform beaches. The latter may

be sandstone, gravel-pebble conglomerate,

beach rock or fossil coral reef consisting of

eroded coral heads in a cemented calcareous

matrix. Wave action on slab beaches is usually

minimal as they are protected by outer reef

crests or occur on the leeward side of land pro-

jections.

The mixed tides have a spring range of about 1

m and a neap range of around 50 cm (Fishelson,

1973; Hulings, unpublished data). The diurnal

inequality averages 4.2 cm for the high tides,

and 4.7 cm for the lows (Hulings, unpublished

data). Fluctuations in sea level of up to 1 m

occur. From December through May, the sea

level is the highest; from July through

September-October it is the lowest (Fishelson,

1973; Hulings, unpublished data). From late

September through November there is a

gradual rise in sea level, and from late May

through June there is a gradual lowering.

There is no river discharge into the Gulf of

Aqaba and this in combination with low rainfall

(23 mm/yr, Morcos, 1970), high evaporation (up

to 4 m/yr, Anati, 1976), prevailing N-NNE, hot

and dry winds (Hulings, 1979) results in a con-

stant salinity of 40.5 to 41.5 ppt (Paldor and

Anati, 1979). The mean air temperature has a

wide range, from about 16°C in January to 32°C

in August (Jordan Meterological Department),

while water temperature has a much narrower

range, from 20°C in February to 27°C, in

August- September (Morcos, 1970).

Methods and Materials

Most of the data on the activity and homing of

Cellana radiata were obtained from specimens

living on a low profile calcareous fossil reef plat-

form in the midlittoral zone above the Tetraclita

zone; additional data on C. radiata were ob-

tained on specimens occurring on large and rela-

tively smooth granitic pebbles. The shells and

the home area were color-coded, using either

enamel paint or fingernail polish. Three color-

coded groups of 15 specimens, each occurring

on the calcareous substratum and averaging

30.1 mm in length, were observed continuously

from 6 October through 7 November 1983 and

periodically through 15 February 1984. The 19

color-coded C. radiata occurring on the granitic

pebbles averaged 24.0 mm in length and were

observed from 6 October through 7 November

1983.

I ii order to obtain informal ion on I lie overall

movement of Cellana radiata, 55 individuals

(average length of 25.4 mm) within a 1 m2 area

were painted and then observed from 11

September through 7 November 1983 on a daily

basis and periodically through mid-June 1984. A

1 m2 metal frame divided into 10 x 10 cm quad-

rates was put in the same place during low tide,

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 77

the time of observation, and removed after each

observation.

For Siphonaria laciniosa, a total of 90 indi-

viduals, averaging 15.2 mm in length, were

color-coded and observed from 10 September

through 9 November 1983 and periodically

through mid-July 1984. The 90 individuals con-

sisted of four separate populations, two of which

consisted of 12 and 34 individuals occurring on

eroded coral reef heads having a very irregular

surface; 25 specimens occurred on a relatively

smooth, cemented, calcareous matrix, and a

fourth population of 16 individuals occurred on

beachrock of cemented granule-sized grains.

Concurrent observations were conducted on six

specimens averaging 13.2 mm in length kept

submerged in an aquarium with running sea

water.

Observations on Cellana radiata and Sipho-

naria laciniosa were made during day and

night, spring and neap tides, flooding and ebb-

ing tides and during complete submergence and

emergence as well as combinations of the above.

Results

Cellana radiata became active soon after sub-

mergence and returned from foraging during

the period from maximum flood tide to just

before or after emergence. Movement during

foraging was not continuous and the distance of

the excursions varied from 3 to 35 cm. The

direction of movement varied from predomi-

nately unidirectional to up to 45° from the main

direction. Limited data indicates that the return

is along the outgoing path. There were individ-

uals that did not forage during consecutive

cycles of submergence. During emergence, C.

radiata remained inactive. The periods of forag-

ing activity and inactivity occurred equally

during day and night.

The homing behavior of Cellana radiata was

extremely variable. Among three groups each of

15 color-coded specimens living on relatively flat

calcareous substrata 38% were initially non-

homers. For the homers, the percent of the in-

dividuals returning to the original home

decreased to 4% over a period of 33 days. Simi-

lar decreases in homing were noted among

other marked specimens on the large and

smooth granitic pebbles. The decrease in the

percent of homers was not, however, constant.

Fluctuations in the percent occurred because of

the return of some individuals to the original

home after one or more days of absence. Many

of those that left the original home subsequently

established one or more new homes. In cases

where the home was occupied by another in-

dividual, the homer returned to as close as possi-

ble to the home but did not dislodge the new

occupant.

The average number of days that Cellana

radiata occupied the original home was 11 and

ranged from 1 to 22. Those specimens occupying

a new home did so for an average of 3 days

(range, 2 to 7).

The homing scar of Cellana radiata on a cal-

careous substratum was either entirely greenish

in color or greenish with the periphery tan to

white. The latter color pattern appeared to be

characteristic of those individuals homing for

extended periods. The color patterns disap-

peared, however, a few days after the home was

vacated. No depressions, excavations or other

physical markings in the scars were seen. Scars

were absent on the hard granitic pebbles. On the

soft calcareous substratum scars from C.

radiata were as small as 11.0 mm in length.

The observations of the 55 marked Cellana

radiata within the 1 m2 area revealed that over

a period of 55 days the number decreased from

55 to 6. The number leaving the area was offset,

however, by immigrants entering the same

area. The exodus was gradual as was the im-

migration into the area. The result was that the

density in the m2 area remained relatively con-

stant, averaging 58 individuals/m2 over a period

of 55 days.

The direction of movement of 55% of the

marked Cellana radiata from the area was

toward the high water mark or vertical while

36% were to either side of the area and approx-

imately parallel to the shoreline. The remaining

8% moved seaward or vertically downward. A

similar pattern of upward and/or lateral move-

ment was noted among non-homing individuals

marked for homing observations. Homing con-

tinued among some individuals while migration

occurred in others. There was no obvious direc-

tional movement of the immigrants into the m2

area although there appeared to be net move-

ment toward the high water mark. During May

and June 1984, a general pattern of seaward

78 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

migration was noted among remnants of the

originally marked populations.

The foraging activity of Siphonaria laciniosa

was restricted when they were submerged and

was begun only after sunset. Activity occurred

either during flooding or ebbing tides but only as

long as the individuals were submerged and

usually within a minimum of 30 minutes after

sunset, but more commonly 45 to 60 minutes

after sunset. Excursions of up to 20 cm and

averaging 54 minutes in length (range, 25 to 100

minutes) occurred. Movement was not con-

tinuous during the foraging excursions. The

return to the home locality was usually along the

outgoing path.

The number of Siphonaria laciniosa within a

particular population foraging at a particular

time was extremely variable. Rarely did all the

individuals of a given population forage during

one period of suitable conditions. In some cases,

there was no foraging among any of the indi-

viduals of a given population on a particular oc-

casion. There appeared, however, to be almost

total foraging activity among all individuals

within a population on successive periods of

suitable conditions.

Without exception, all Siphonaria laciniosa

homed following the foraging excursions, in-

cluding specimens continually submerged in an

aquarium. Furthermore, the homing was found

to be rigid in that it was continuous over the

period from 10 September through 9 November

1983. An exception was in three specimens

which moved to a new home but subsequently

remained at the new home. Observations

through mid- July 1984 revealed all of the

originally observed S. laciniosa occupying the

same homes.

The scar of Siphonaria laciniosa occurring on

calcareous substrata was white in the center and

green on the periphery. The coloration disap-

peared, however, within a few days after the

home was no longer occupied. The scar was

usually a depression, part of which was com-

monly surrounded by a ridge. The surface of the

depression tended to be smoother than the sur-

rounding substratum. The depressions were

generally more common among large than small

specimens. Among both large and small individ-

uals, the edge of the shell conformed to the con-

figuration of the substratum.

Scars with the coloration pattern and depres-

sion were absent among Siphonaria laciniosa

occurring on hard, non-calcareous substrata

such as granular beach-rock and pebbles.

Among these homing individuals, the edge of

the shell conformed to the surface configuration

of the substratum regardless of the irregularity.

Discussion

The patterns of foraging activity and homing

in the two rocky intertidal limpets along the

coast of Jordan are very different. The patellid,

Cellana radiata, is a temporary or non-rigid

homer, as well as being migratory. In addition,

it is active both day and night but forages only

when submerged. In contrast, the pulmonate,

Siphonaria laciniosa, is a rigid homer and does

not migrate; foraging occurs only after sunset

and when it is submerged. The patterns of activ-

ity in both species occurred irrespective of tidal

or lunar cycles.

Rao and Ganapati (1971) reported that Cel-

lana radiata from the tropical west coast of

India exhibited homing behavior but with no in-

dication of whether homing was temporary or

permanent. They further reported that homing

occurred only on rough substrata and not on

smooth surfaces and that movement occurred

only during submergence. Cellana radiata from

the Jordan Gulf of Aqaba has been found to

home temporarily on smooth, as well as rough

surfaces.

Cellana radiata from the Jordan Gulf of

Aqaba exhibits the same temporary homing be-

havior as reported by Branch (1975) for Patella

(jranularis Limit' and by Macka\ and Under-

wood (1977) for C. tramoserica (Sowerby). In

addition, C. radiata generally fits the category

of migratory species established by Branch

(1981) for Patella spp. The homing behavior

found in Siphonaria laciniosa is consistent with

that of other siphonariids (Branch, 1981 and in-

cluded references). The conditions and timing of

foraging excursions in S. laciniosa are,

however, different from that of other species

summarized by Branch (1981) in occurring only

when submerged and after sunset.

Homing behavior among intertidal limpets is

often considered as a response to minimizing

desiccation. In the case of the homing behavior

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 79

of Cellana radiata reported here, homing is

considered insignificant in relation to desicca-

tion. C. radiata is a temporary homer with a

temporary scar and the edge of the shell usually

does not fit closely to the substratum. In addi-

tion, during emersion the shell is raised from the

substratum rather than being clamped down,

the mantle cavity contains copius fluid and there

is no formation of a mucus sheet reported by

Wolcott (1973).

In the case of Siphonaria laciniosa, however,

homing is considered significant in reducing

desiccation. S. laciniosa, a rigid homer, returns

to a permanent scar following foraging and

there is a good fit of the edge of the shell to the

substratum on soft (calcareous) and hard bot-

toms. And during emersion, the shell is clamped

to the substratum.

The significance of homing in Cellana radiata

may be related to what Mackay and Underwood

(1977, p. 215) proposed for Cellana tramoserica

which, as noted above, are similar in homing

behavior. They hypothesized "homing behavior

as an adaptation which regulates local density

and dispersion to maximize utilization of food

resources and, thus, to reduce intraspecific com-

petition for food at high densities of limpets".

Support for this hypothesis in C. radiata may be

found in the results of the movement through a

1 m2 area over a period of 58 days. During that

period there was gradual emigration of marked

individuals from the area and gradual immigra-

tion of new individuals into the area. The result

of the emigration and immigration was that the

density of individuals within the unit area re-

mained relatively constant.

The pattern of shoreward or upward migra-

tion in Cellana radiata during late September

through November is considered as a response

to the increase in sea level, increased food sup-

ply and reduced physical extremes. As noted

above, late September through November is the

period of transition from lowest sea level (July

through mid-September) to highest sea level

(December through May). With an increase in

sea level, more area is submerged for a longer

period of time thus favoring increased food sup-

ply in the form of microalgae and a reduction in

physical extremes. Thus, C. radiata, microalgal

grazer and feeding only when submerged, takes

advantage of the increased area of suitable con-

ditions. The observed seaward or downward

movement of C. radiata that occurred begin-

ning in late May more or less coincided with a

gradual lowering of the sea level. It is con-

sidered as an attempt to avoid the greater ex-

tremes in the physical environment and reduced

food supply. A similar pattern of migration

described above with, however, varying

degrees, has been found among some proso-

branch gastropods occurring in the rocky inter-

tidal on the Jordanian coast (Hulings, unpub-

lished data).

Siphonaria laciniosa responds in different

ways to the change in sea level. As a non-

migrant, it remains in the same position regard-

less of the change in sea level. During the period

of high sea level, it is submerged more often and

for a longer period of time. It is during this

period that S. laciniosa deposits egg ribbons

during the night on exposed surfaces and that

the hatching of veligers occurs (Hulings, in

preparation). During the period of lowered sea

level, air temperatures are higher and periods of

emergence are longer. Thus, homing behavior

as a response to lowered sea level minimizes

desiccation.

Although an investigation of predation was

not conducted, observations indicate a high mor-

tality rate in Cellana radiata compared to

Siphonaria laciniosa based on the finding of

empty shells on the beach. A mortality rate of

22% was found among marked S. laciniosa over

a 10-month period (no comparable data for C.

radiata). What portion of the mortality is attri-

butable to predation is not known. Most of the

empty shells of both limpets did not exhibit

physical damage.

The spatial distribution of Siphonaria

laciniosa tends to be more clumped than widely

dispersed. Pairs and groups of individuals occur-

ring in close proximity to each other are fairly

common. Recruitment into areas of established

populations was noted, and in some cases, the

recruits were close to older individuals. Thus,

there appears to be no aggressive behavior nor

territorial defense by S. laciniosa. A similar

situation probably prevails in Cellana. radiata

based on homers not dislodging new occupants.

Limited data and observations show that

where Cellana radiata is abundant, Siphonaria

laciniosa is very low in abundance or absent and

80 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

vice versa. This pattern of density distribution

often exists at the same vertical level within the

midlittoral zone. Whether this indicates inter-

specific competition between the two limpets re-

mains to be elucidated. In addition, the area

occupied by Cellana radiata is usually devoid of

microalgal grazers other than Siphonaria

laciniosa and vice versa. It would appear, there-

fore, that competition for food is minimal.

Acknowledgments

The author wishes to thank Dr. Joseph Rose-

water, U.S. National Museum of Natural

History, for verification of the identification of

the species. Thanks are also expressed to Dr.

Jean de Vaugelas, University of Nice, for

critical reading of the manuscript. Financial

support by the Office of the Dean Resource,

Yarmouk University is greatly acknowledged.

LITERATURE CITED

Anati, D. A. 1976. Balances and transports in the Red Sea

and the Gulf of Elat (Aqaba). Israel J. Earth Sci. 25:

104-110.

Branch, G. M. 1975. Mechanisms reducing intraspecific com-

petition in Patella spp.: migration, differentiation and

territorial behavior. J. Anim. Ecol. 44:575-600.

1981. The biology of limpets: physical factors.

energy flow, and ecological interactions. Oceanogr. Mar.

Biol. Ann. Rev. 19:235-380.

Fishelson, L. 1973. Ecological and biological phenomena

influencing coral-species composition on the reef tables at

Eilat (Gulf of Aqaba, Red Sea). Mar. Biol. 19:183-196.

Garrity, S. D. and S. C. Leving. 1983. Homing to scars as a

defense against predators in the pulmonate limpet Sipho-

naria gigas (Gastropoda). Mar. Biol. 72:319-324.

Hulings, N. C. 1979. Currents in the Jordan Gulf of Aqaba.

Dirasat 6:21-33.

Mackay, D. A. and A. J. Underwood. 1977. Experimental

studies on homing in the intertidal patellid limpet

Cellana tramoserica (Sowerby). Oecologia 30:215-237.

Morcos, S. A. 1970. Physical and chemical oceanography of

the Red Sea. Oceanogr. Mar. Biol. Ann. Rev. 8:73-202.

Paldor, N. and D. A. Anati. 1979. Seasonal variations of

temperature and salinity in the Gulf of Elat (Aqaba).

Deep-Sea Res. 26:661-672.

Rao, M. B. and P. N. Ganapati. 1971. Ecological studies on a

tropical limpet, Cellana radiata. Mar. Biol. 9:109-114.

Safriel, U. and Y. Lipkin. 1964. On the intertidal zonation

of the rocky shores at Eilat (Red Sea, Israel). Israel J.

Zool. 13:187-190.

Stephenson, T. A. and A. Stephenson. 1949. The universal

features of zonation between tidemarks on rocky coasts.

J. Eeol. 37:289-305.

Underwood, A. J. 1979. The ecology of intertidal gastro-

pods. A dv. Mar. Biol. 16:111-210.

Wolcott, T. G. 1973. Physiological ecology and intertidal

zonation in limpets (Acmaea): a critical look at "limiting

factors". Biol. Bull. 145:389-422.

MEETINGS

Western Society of Malacologists

August 18-21, 1985

The annual meeting of the Western Society of

Malacologists will be held on the campus of the

University of California, Santa Barbara. The

main emphasis will be on the molluscan fauna of

the Eastern Pacific with sessions including land

snails, paleontology, etc. There will also be a

symposium on Hawaiian mollusks chaired by

Mrs. Beatrice Burch.

Anyone interested in pre-registration or call

for papers please contact William D. Pitt, presi-

dent, WSM, 2444 38th Ave., Sacramento, CA

95822. Telephone (916) 428-3899, home even-

ings.

DEATHS

Joseph Rosewater, 1928 - 1985

Joseph Rosewater, Curator of Mollusks at the

U.S. National Museum since 1960, a past-Presi-

dent of the American Malacological Union, and

a long-time contributor to The Nautilus, died

after a relatively short illness on March 22,

1985, in Washington, DC, at the age of 56. He is

survived by a son, two daughters and his widow,

Mary Carlson Rosewater, 818 Woodley Drive,

Rockville, MD 20850. An obituary and list of his

publications will appear in the joint Clench-

Rosewater memorial issues of the 100th Anni-

versary volume of The Nautilus in 1986. We are

informed that a fellowship fund for visiting

mollusk students will be set up at the Smith-

sonian Institution in memory of Dr. Rosewater.

Vol. 99 (2-3)

April 29, 1985

THE NAUTILUS 81

THE LAND SNAIL FAMILY HYDROCENIDAE IN VANUATU

(NEW HEBRIDES ISLANDS), AND COMMENTS ON

OTHER PACIFIC ISLAND SPECIES

Fred G. Thompson

Florida State Museum

University of Florida

Gainesville, FL 32611

and

Emilye L. Huck

P.O. Box 4413

Winter Park, FL 32793

ABSTRACT

Georissa obsoleta new species (Gastropoda, Prosobranchia, Archeogastropoda,

Hydrocenidae) is described from- Efate Island, Republic of Vanuatu. It is charac-

terized by its minute size, obsolete sculpture, channelled suture, and conical form.

It is the first record of Hydrocenidae from Vanuatu. Relationships with other

Pacific species are not clear. The Hawaiian Georissa neili Pilsbry, 1928 is

synonymizedwithG. cookei Pilsbry, 1928. G. kauaiensis Pilsbry, 1928 (Hawaiian

Islands). Chondrella striata Pease, 1871 (Cook Islands), and Cyclostoma

minutissima Sowerby, 1832 (Pitcaim Island) are based on juvenile specimens but

appear to be Georissa.

Key words: land snails, Hydrocenidae, Georissa obsoleta, Pacific Islands,

Vanuatu, New Hebrides Islands, Efate Island.

During June- August, 1984 the junior author

had the opportunity to visit the Republic of

Vanuatu, formerly called the New Hebrides

Islands. Significant collections of land snails

were made on Efate, Erromango, and Tanna.

The collections are particularly interesting

because of the large number of minute species

that were recovered from leaf-litter samples

gathered at many stations. A species of par-

ticular interest to us is described below. It is the

first record of the family Hydrocenidae from

Vanuatu.

Hydrocenid land snails are widely deployed on

Pacific islands, Japan, New Zealand, Australia,

the Indo-Australian archipellago, Southeast

Asia, Madagascar, Africa, and Mediterranean

Europe. They are poorly known because of their

minute size and cryptic behavior, although they

may be locally abundant (Thompson and Dance,

1983). Most species are confined to limestone

substrates and encrust their shells with lime or

mud. Live specimens appear more like minute

blobs of dirt than like coiled shells. Thus, it is not

surprising that this family was not reported in

the two principal papers on the New Hebrides

fauna (Solem, 1959, 1962). Because the new

species has very poorly developed shell

sculpture we name it:

Georissa obsoleta

Thompson and Huck, new species

Shell (Figs. 1-7): Minute, adults about 1.7-1.9

mm long, about 0.72-0.78 times as wide as high.

Color varying from yellow-gray to fulvous in

fresh shells. Conical with a wide rounded apex;

consisting of 3.3-3.7 whorls. Apex rounded, with

a large cap-shaped protoconch consisting of 1.3

whorls (Fig. 6). Protoconch sculptured with a

dense mesh of minute pits. Suture between

whorls of teleoconch very deeply impressed,

forming a channel around middle of shell (Fig.

5). Sculpture of teleoconch consisting of very

weakly developed spiral threads that form an

obsolete cancellate pattern where they cross

growth striations and threads (Fig. 2). Growth

threads tend to be enlarged above shoulder of

whorl and usually form weak denticles along

second and third whorls (Fig. 5). Aperture ovate

in shape, about as wide as or slightly wider than

high; about 0.39-0.48 times length of shell.

Parietal wall nearly straight, lying at an angle

of 30-32° to axis of shell (30° in holotype); plane

of aperture at 20-25° to shell axis (Fig. 3). Um-

bilical area with a wide shield that is indented

along outer edge (Fig. 7). Parietal septum ex-

tending into shell for % whorl, where upon the

earlier septum has been readsorbed (Fig. 4).

82 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

'

©

L-9 Georissa obsoleta Thompson and Huck, new species. 1. UF 50628a (x31). 2, UF 50629a(x31). 3. UF 50629a

i F 50627 (x31). 5, UF 50628b (xl64). 6, UF 50628b ( x 205). 7, UF 50628a(x62). 8. inner surface of operculum

i 9, oblique view of operculum at 70° from base (x82).

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 83

Measurements for the holotype and five para-

types (UF 50633) selected to show variation

follow:

length width apert. h apert.

whorls

1.64

1.89

1.80

1.71

1.61

1.24

1.40

1.40

1.27

1.24

0.74

0.76

0.84

0.74

0.74

0.74

0.87

0.84

0.74

0.74

3.6

3.7

3.6

3.5

3.1

holotype

paratype

paratype

paratype

paratype

Operculum (Figs. 8, 9): Calcareous, concentric

with a large subcentral nucleus. Inner surface

with a long slender peg along columellar

margin. Peg lying at a relatively low angle to

plane of operculum; dorso-ventrally flattened;

base of peg extending out to columellar edge of

operculum. Innter surface of operculum flat,

with a narrow raised callus around edge (Fig. 8),

but not to the extent that occurs in Chondrella

parva (Pease, 1864).

Type locality: Vanuatu, Efate Island, above

Mele village along trail to the cascades, 75 m

altitude. Holotype: UF 50631; collected 23 June

1984 by Emilye L. Huck. Paratypes: UF 50632

(57), UF 50633 (13 measured specimens), UF

50634 (11), UF 50627 (1 gold plated), UF 50628

(2 gold plated), UF 20629 (2 gold plated),

Bernice P. Bishop Museum 207565 (6), Austra-

lian Museum C144145 (5), Rijksmuseum van

Natuurlijke Historie 55724 (5); same locality as

holotype.

The type series was collected from leaf-litter

samples gathered at the base of a limestone

knoll at the edge of a banana grove in a dense

rain forest, along the cascades of a small river

near Mele village. Most of the specimens are

slightly weathered. A few specimens are in

fresh condition and retain the natural color. The

holotype is a slightly immature specimen

selected because it is the freshest specimen in

the lot, it shows details of sculpture and color

and the operculum is retained within the aper-

ture. The paratypes illustrated in Figs. 1, 2 (UF

50628a) are nearly identical to the holotype but

are very slightly larger. The figured operculum

was recovered from a paratype (UF 50632).

features distinguish the species from all other

known Pacific Georissa. Five other species are

described as being smaller, but their original

descriptions appear to be based on juveniles and

better material has not been reported.

It is difficult to determine specific relation-

ships because very little is known about the

Pacific Hydrocenidae. Six species have been

described from the northern and eastern

Pacific. Three are recorded from Kauai,

Hawaiian Islands, Georissa cookei Pilsbry, 1928,

G. neili Pilsbry, 1928, and G. kauaiensis Pilsbry,

1928. The three were recovered from moss

samples collected from fallen logs on a ridge be-

tween Hanalei and Wailua. The type specimens

of all three are juveniles, and each is known

from only one or two specimens. On the basis of

variation that we have seen in other species (see

Thompson and Dance, 1983) we suspect that G.

cookei and G. neili are the same species, and we

have little faith in the distinction of G. kauaien-

sis. Regardless of their specific status, their

juvenile shells do not permit comparisons with

other species because definitive characteristics

of size, shape, sculpture and whorl development

cannot be determined.

One species is known from the Cook Islands,

Chondrella striata Pease, 1871, and one is

described from Pitcairn Island, Cyclostoma

minutissima Sowerby, 1832. Both appear to be

typical Georissa and both are based on juvenile

shells. Thus it is not possible to discuss their

characteristics for the purpose of specific com-

parisons, other than to say that they are sculp-

tured more heavily than is G. obsoleta.

Another species is recorded from the Society

Islands, Cyclostoma parva Pease, 1864. It is

much larger and smoother than G. obsoleta, and

is placed in a separate genus, Chondrella,

because of a heavy callused ridge around the in-

side margin of the operculum.

Other species are known from New Zealand,

Australia, and islands to the north, but close

relationships between G. obsoleta and these are

not apparent.

Discussion

Georissa obsoleta is characterized by its

minute size, its moderately wide, conical form,

its channelled suture, and its sculpture. These

Acknowledgments

The junior author traveled to the Republic of

Vanuatu (New Hebrides Islands) assisted by a

grant provided by The Explorers Club Educa-

84 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

tion and Youth Activities Fund and the Haver-

lee Exploration Fund of the Central Florida

Chapter of The Explorers Club. We wish to ex-

press our gratitude to the society for this aid,

and to Dr. R. Tucker Abbott for his encourage-

ment. She was accompanied in the field by her

mother, Robin B. Huck. Harvey A. Miller

(University of Central Florida) led the expedi-

tion while pursuing studies on Pacific bryo-

phytes under the sponsorship of the National

Science Foundation (Grant BSR-8215056). The

SEM micrographs comprising the illustrations

in this paper were prepared by Kurt Auffenberg

(Florida State Museum) from the HITACHI

S415A Scanning Electron Microscope in the

Department of Zoology, University of Florida.

George M. Davis (Academy of Natural Sciences,

Philadelphia) loaned us specimens of Cyclostoma

parva Pease for comparison. A discussion of its

specific and generic status will be presented

elsewhere by the senior author. We wish to ex-

press our gratitude to all people who have

assisted us in this study.

LITERATURE CITED

Pease, W. H. 1864. Descriptions of new species of land

shells from the islands of the Central Pacific. Proe. Zool.

Soc. Lond. for 1864: 668-678.

1871. Catalogue of the land shells inhabiting

Polynesia, with remarks on their synonymy, distribution

and variation, and descriptions of new genera and species.

Proc. Zool. Soc. Lond, for 1871: 449-477.

Pilsbry, H. A. 1928. Georissa, a land snail genus new to the

Hawaiian Islands. Bull. Bernice P. Bishop Mus. 47:3-4.

Solem, A. 1959. Systematica of the land and freshwater

Mollusca of the New Hebrides. Fieldiana (Zool.) 43:

1-238; pis. 1-34.

1959. Notes on. and descriptions of New

Hebridean land snails. Bull. British Mus. (Nut Hist.)

9:213-247; pis. 1-2.

Thompson, F. G. and S. P. Dance. 1983. Non-marine mol-

lusks of Borneo. II Pulmonata: Pupilliade, Clausiliidae.

Ill Prosobranchia: Hydrocenidae, Helicinidae. Bull. Fla.

Stat. Mus. (Biol. Sci.) 29(3): 101-130; Figs. 1-75.

COMMENTS ON THE DISTRIBUTION OF FRESHWATER MUSSELS

(UNIONACEA) OF THE POTOMAC RIVER HEADWATERS

IN WEST VIRGINIA

Ralph W. Taylor

Department of Biological Sciences

Marshall University

Huntington, WV 25701

ABSTRACT

This report presents data collected in 1981 and 1984 on the mussels of the upper

Potomac River located within the eastern panhandle of West Virginia. My data

indicate that North Branch is devoid of mussels apparently as a result of extensive

strip mining; South Branch has a small but healthy mussel population. The

Cacapon River and Patterson Creek, tributaries to the Potomac, also have viable

populations. Eight species of mussels were found in the Potomac headwaters.

Elliptio complanata, E. fisheriana and Lampsilis ventricosa were fairly common

and Alasmidonta varicosa, A. undulata, Anodonta cataracta, Strophitus undu-

latus, and Lasmigona subviridis were uncommon throughout the system. Cor-

bicula fluminea was found throughout the drainage with the exception of North

r.nnich.

The freshwater mussel fauna of the Potomac

River headwaters is virtually unknown. Ort-

mann (1919) has done the only previous exten-

sive collecting in the region, and that was com-

pleted around the turn of the twentieth century.

He probably took a train to Romney, West

Virginia, and then to Harpers Ferry to collect in

the Potomac River over a distance that could be

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 85

covered in a day's ride by buggy. All of his

records are in the immediate area of these two

towns. Johnson (1970) reported that Carol Stein

did limited collecting at Harpers Ferry in the

early sixties. I can find no evidence of other

work having been done in the upper Potomac

River.

The reasons for the paucity of work there in-

clude: very poor roads (until recently) into the

area; a very difficult terrain to maneuver; and

limited access to the river at any point.

Clarke (1981), Johnson (1970), and Ortmann

(1919) all indicated a depauperate assemblage of

mussels in this stream. My report does not

dispel those findings. There are small popula-

tions present but they are widely spread and oc-

cur more often in the smaller tributaries than in

the main trunk of the river. The only population

of considerable size that I found was located at

an area locally known as Pack Horse Ford, just

downstream of Sheperdstown, West Virginia.

All other areas reported herein represent small

populations of no more than a couple of dozen

specimens from any one site.

The Potomac River originates in the Potomac

highlands in the eastern panhandle of West

Virginia. The mainstem Potomac River then

continues along the Maryland/West Virginia

border for Ca. 160 km to Harpers Ferry where it

receives the Shenandoah River which has its

headwaters in Virginia. I have not collected

below Harpers Ferry. Two other major tribu-

taries in West Virginia are the Cacapon River

and Patterson Creek (Fig. 1).

Ortmann (1919) collected in the South Branch

Potomac River at Romney and Southbranch and

reported the following species: Elliptio com-

planata (Lightfoot, 1786), Lasmigona subviridis

(Conrad, 1835), Anodonta cataracta Say, 1817,

Strophitus undulatus (Say, 1817) and Alasmi-

donta varicosa (Lamarck, 1819). He also

reported E. complanata and A. varicosa from

the Shenandoah River at Harpers Ferry. Clarke

(1981) reported Alasmidonta undulata (Say,

1817) from the South Branch and Shenandoah

rivers and A. varicosa from Cherry Run and

Lost River, a small tributary of the Cacapon

River. Johnson (1970) reported two additional:

Lampsilis ventricosa (Barnes, 1823) and Ellip-

tio fisheriana (Lea, 1838) [ = lanceolata (Lea,

1820)]. The Cacapon River and Back Creek are

FIG. 1. Headwaters of the upper Potomac River.

listed as the localities where these two mussels

were collected.

My collecting was done during the summers of

1981 and 1984. Collecting involved wading the

streams and collecting specimens that had been

observed through the use of a glass-bottomed

viewbox (waterscope). The entire drainage was

covered to the extent that it was practical. Many

areas are virtually inaccessible and could be

reached only by raft or canoe. The sites reported

herein are the only ones where mussels were

found in any appreciable numbers. At all other

localities visited only an occasional isolated in-

dividual was seen and seemed not to represent a

viable population. Voucher specimens have been

placed with the Ohio State University Museum

and the Marshall University Malacological Col-

lections.

Collecting Sites

1. Potomac River at Pack Horse Ford, approx-

imately 1 km E of Sheperdstown, Jefferson Co.,

WV, off County Road (CR) 17/1.

2. South Branch at U. S. Route (US) 50

Bridge, 1 km W of Romney, Hampshire Co.,

WV.

3. South Branch at Arnold Farm, S of Romney

on CR 8/2, 9 km N of Hardy Co. line Hampshire

Co., WV.

86 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

4. South Branch, off CR 6, N of Village of

Cunningham, Hardy Co., WV.

5. South Branch, bridge on US 220 at Peters-

burg, Grant Co., WV.

6. Cacapon River, off SR 9, 5 km N of Village

of Largent, Morgan Co., WV.

7. Cacapon River, along CR 15 at public fish-

ing area, Hampshire Co., WV.

8. Cacapon River, 1.5 km S of Village of

Capon Bridge on CR 14, Hampshire Co., WV.

9. Cacapon River at bridge on CR 9/12,

Morgan Co., WV.

10. North River of Cacapon River, along

Delray Road ( = CR 11), Hampshire Co., WV.

11. Patterson Creek, along CR 46 near Fort

Ashby, Mineral Co., WV.

12. Patterson Creek, at intersection of CR

28/3 and CR 28/10, Mineral Co., WV.

13. Shenandoah River, at Harpers Ferry,

Jefferson Co., WV.

Discussion

There are areas in the headwaters of the

Potomac River drainage where small popula-

tions of naiads still persist. The North Branch of

the Potomac River, however, has no detectable

mussel population. All the collecting sites

showed signs of mining damage. The substra-

tum was covered with heavy deposits of ochre

indicating the presence of mining effluent. Cor-

bicula Jluminea (Miiller, 1774) which was found

everywhere else in the drainage, was not found

in this major tributary of the Potomac. The rest

of the headwaters showed little evidence of

disturbance by man. Presently, most of the area

is fairly pristine with no industry or logging ac-

tivities. Farming centers around the production

of apples so there is little stream siltation.

Species Accounts

Elliptio complanata: This species was the

most commonly found species in the study area

and was found at nearly every collection site.

Elliptio fisheriana: Johnson (1970) stated that

this may simply represent a northern form of

Elliptio lanceolata. E. fisheriana is, however,

being recognized by the committee of the

American Malacological Union which is current-

ly preparing a list of generally accepted names

for the naiads. While never found in abundance,

it is widespread throughout the headwaters.

Lampsilis ventricosa: This species is normally

an interior basin species. It was inadvertently

introduced into the Atlantic drainage about the

turn of the century. It has become well estab-

lished and is quite common throughout much of

the drainage. It has apparently replaced the

resident species Lampsilis cariosa (Say, 1817)

in the upper Potomac River. The Ohio State

University Museum of Zoology has several

specimens of L. cariosa from the lower Potomac

TABLE 1. Distribution of naiad mussels in the headwaters of the Potomac River system

by species.

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 87

but none from this reach (Stansbery, 1984, pers.

comm.).

Ahisiiiiilniiii! varicosa: Apparently fairly com-

mon throughout the headwaters. Widespread

throughout the Atlantic coastal drainages.

Alasmidonta undulata: This species is ap-

parently quite rare here as only five specimens

were found. Widespread throughout the Atlan-

tic coastal drainages.

Anodonta cataracta: This species does not ex-

hibit a widespread distribution in the head-

waters. It is typically found in larger, slower-

flowing bodies of water. Only four specimens

were found during this study.

Lasmigona subviridis: This small species may

be more abundant than my collections indicate.

It is a typical Atlantic coastal species and enjoys

a widespread distribution in most of eastern

North America. It has crossed the mountain

barrier on at least one occasion and can be found

in the New River system (a tributary of the Ohio

River) of southern West Virginia. One specimen

was found at each of three different collecting

stations during this study.

Strophitus undulatus: This species is not com-

mon. Ortmann (1919) reported it only from

South Branch at Romney. I found a single live

specimen in Patterson Creek and a badly-

weathered half shell in the Shenandoah River.

LITERATURE CITED

Clarke, A. H. 1981. The Tribe Alasmidontini (Unionidae:

Anodontinae), Part I: Pegias, Alasmidonta, and Arcidens.

Smithsonian Contributions to Zoology. No. 326, 101 p.

Johnson, R. I. 1970. The Systematies and Zoogeography of

the Unionidae (Mollusca: Bivalvia) of the Southern Atlan-

tic slope Region. Bulletin of the Museum of Comparative

Zoology. No. 140(6):263-449.

Ortmann. A. E. 1919. A monograph of the Naiads of Penn-

sylvania. Part 3. Systematic account of the genera and

species. Memoirs of the Carnegie Museum 8:1-384.

A SECOND MELAMPID (PULMONATA: BASOMMATOPHORA)

FROM THE EARLY MIOCENE OF VENEZUELA

J. Gibson-Smith and W. Gibson-Smith

Quinta Puerta del Sol, Calle Tucupido, San Roman, Las Mercedes,

Caracas 1060, Venezuela

ABSTRACT

Pedipes cf. P. mirabilis (Muhlfeld, 1816) was reported by the present authors

(1979, p. 22) from the early Miocene (Burdigalian) Cantaure Formation,

Paraguand Peninsula, Venezuela, being the first reported fossil occurrence of the

genus. It is described now as the new species Pedipes mirandus and is considered

to be the ancestor of the Recent cognate species P. angulatus C. B. Adams, 1852,

from the Eastern Pacific and P. mirabilis from the Western Atlantic.

The presence in the early Miocene (Burdi-

galian) Cantaure Formation, Paraguana Penin-

sula, Venezuela, of two members of the family

Melampidae was reported by Gibson-Smith &

Gibson-Smith (1979, p. 22). One of these, Tralia

cf. T. ovula (Bruguiere, 1789), was later de-

scribed by these authors (1982, p. 119) as the

new species T. venezuelana, which lives along

the north coast of Venezuela, occurring also in

the late Pliocene Mare Formation, Cabo Blanco,

Venezuela. This was only the second fossil

record of the genus Tralia the other being T.

vetula Woodring, 1928, from the Pliocene

Bowden Formation, Jamaica. The second Can-

taure form, Pedipes cf. P. mirabilis (Muhlfeld,

1816), the first fossil record of the genus, is

likewise now recognized as a new species,

Pedipes mirayidus. It is considered to be the

ancestor of the Recent cognate species P.

angulatus C. B. Adams, 1852, from the Eastern

Pacific and P. mirabilis from the Western

Atlantic. The genus was reviewed by Clench

88 THE NAUTILUS

April 29, 1985

Vol. 99(2-3)

(1964, p. 119) and the only other Recent taxa of

the region are P. liratus Binney, 1860, and P.

unisulcatus Carpenter, 1866, both from the

Eastern Pacific.

The author of Pedipes was said by both Clench

(loc. cit.) and Keen (1971, p. 848) to be Ferussac,

1821, the former giving the type species as,

"Pedipes afra Gmelin ( = P. pedipes Bruguiere),

subsequent designation, Gray 1847." Abbott

(1974, p. 333), on the other hand, gave the

author as Bruguiere, 1792, with type species

[Helix] afer Gmelin. According to Clench (loc.

cit.) afer is a Pfeiffer, 1856, misspelling of afra.

Zilch (1959, p. 68) was the first to name

Bruguiere, 1792, as the author, the type species

being Bulimus pedipes Bruguiere, 1789, by

tautonymy.

Subfamily Pedipedinae Crosse & Fischer, 1880

Genus Pedipes Bruguiere, 1792

Type species, by tautonymy, Bulimus pedipes

Bruguiere, 1789.

Pedipes mirandus

Gibson-Smith & Gibson-Smith, n. sp.

Figure 1

Description: Shell minute. Protoconch hetero-

strophic, submerged, last V2-whorl inclined,

smooth. Teleoconch of 3Vi shouldered whorls,

body whorl globose. Sculpture of flat, subequal

spiral cords with narrower interspaces, sub-

sutural cord prominent; 4 cords between it and

the shoulder and about 23 below. Surface rough-

ened by crowded, prosocline growth incremen-

tals. Columella broad, inclined, with two in-

clined folds, the lower the weaker. Parietal

callus narrow, carrying a large fold lying closer

to the anal notch than to the upper columellar

fold. Outer lip thin, smooth within.

Holotype: Natural History Museum Basel, No.

H 17113. Height 2.25 mm, diameter 1.75 mm.

Type locality: Known only from the lower shell-

bed of the early Miocene Cantaure Formation,

Paraguana Peninsula, Venezuela (GS-1-PGNA).

Paratype: Paleontological Research Institution,

PRI 30049.

Remarks: The type material consists of 5

small, complete specimens and, in the absence

of even fragments of larger shells, are believed

to be mature. While the absence of a labral den-

ticle might suggest immaturity it is not a

FIG. 1. Pedipes mirandus n. sp. Holotype, ventral view.

Height 2.25 mm, diameter 1.75 mm. Early Miocene Can-

taure Formation. Paraguana Peninsula, Venezuela. NHMB

H 17113. SEM micrograph, x25.

characteristic of all mature Pedipes, the equally

small P. liratus also lacking a denticle (Keen,

1971, fig. 2411). Comparison has been made

with juvenile P. mirabilis of a similar size. The

trivial name is from the same Latin root as

mirabilis meaning "wonderful" or "singular".

Comparisons: P. mirandus n. sp. is most

closely related to P. angulatus and P. mirabilis,

the sculpture and outline being similar. In its

broad columella it more resembles P. angulatus

and in the reduced extent of the parietal callus it

more resembles P. mirabilis. It differs from

both in being smaller with 1 or 2 fewer whorls,

in having an inclined columella and inclined col-

umellar folds, the lower smaller than the upper;

in P. angulatus and P. mirabilis the columella is

vertical, the folds are about equal in size and are

horizontal. In both of these, moreover, the

parietal folds lies midway between the upper

columellar fold and the anal notch, whereas in P.

mirandus the fold lies closer to the anal notch,

dividing the gap into one-third and two-thirds,

and it is more horizontally directed.

LITERATURE CITED

Abbott, R. T. 1974. American Seashells, 2nd edit., 663 pp.,

24 col. pis., text figs. Van Nostrand Reinhold Co., New

York.

Clench, W. .1. 1964. The genera Pedipex and Lacntadontti

Vol. 99(2-3)

April 29, 1985

THE NAUTILUS 89

in the Western Atlantic. Johnsonia 4(42):117-127,

pis. 76-79.

Gibson-Smith, J. and W. Gibson-Smith. 1979. The genus

Arcinella (Mollusca: Bivalvia) in Venezuela and some

associated faunas. Geos No. 24, pp. 11-32, 3 pis.

1982. The subfamily Melampinae (Pulmonata:

Basommatophora) in Venezuela, with descriptions of two

new species. TheNautilus 96(3):1 16-120, 9 figs.

Keen, A. M. 1971. Sea shells of tropical West America;

marine mollusks from Baja California to Peru. 2nd. edit.,

Stanford Univ. Press, Calif., i-xiv + 1064 pp., ca. 4000

text figs., 22 col. pis.

Zilch, A. 1959. Gastropoda: Euthyneura. In Wenz's Hand-

buch der Palaozoologie. Lief. 1, pp. 1-200.

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OCTOBER 31, 1985

THE

NAUTILUS

ISSN 0028-1344

Vol. 99

No. 4

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