European Journal of Taxonomy 41: 1-110

http://dx.doi.org/10.5852/ejt.2013.41

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2013 • Bjorn Kroger

Monograph

um:lsid:zoobank.org:pub:A2FlB9ED-870A-466E-B35E-BD5DA782476E

The cephalopods of the Boda Limestone, Late Ordovician, of Dalarna,

Sweden

Bjorn KROGER

Museum far Naturkunde, D-10115 Berlin, Invalidenstrasse 43, Germany.

Currently: Museum of Evolution, Uppsala University, Norbyvagen 16, and Department of Earth

Seienees Palaeobiology, Villavagen 16, SE 752 36 Uppsala, Sweden.

E-mail: [email protected]

um:lsid:zoobank.org:author:72F166B6-51DC-4DD8-9DEE-47EDDEE3D2F2

Abstract. The late Katian, Fate Ordovieian Boda Eimestone of Dalama, Sweden eontains a rieh

eephalopod assemblage. The assemblage eonsists of 61 speeies, in 31 genera, eomprising almost all

major Ordovieian eephalopod orders. Most eommon and diverse are the Orthoeerida. The Aseoeerida

are also remarkably eommon and diverse. The new aseoeerid speeies, Redpathoceras bullatum sp. nov.,

R. depressum sp. nov., R. magnum sp. nov., and Probillingsites scandinavicum sp. nov., give reason

to revise eurrent hypotheses on the origin and evolution of this group. An aseoeerid origin from

barrandeoeeratids or aspidoeeratids is hypothesised. The absenee of aetinoeerids in the Boda Eimestone

is notable, and is interpreted as an indieation of relatively eool and/or deep depositional environments.

The dominanee of orthoeerids is provisionally interpreted as evidenee for nutrient-rieh waters during

the time of the deposition of the Boda Eimestone. Additionally, the assemblage eontains the new

barrandeoeerids Schuchertoceras fryi sp. nov., Siljanoceras varians gen. et sp. nov., Warburgoceras

gen. nov. (for Cyrtoceras longitudinale Angelin in Angelin & Eindstrom, 1880), the new endoeerid

Cameroceras turrisoides sp. nov., the new oneoeerid Cyrtorizoceras thorslundi sp. nov., and the new

orthoeerids Dawsonoceras stumburi sp. nov., Isorthoceras angelini sp. nov., /. curvilineatum sp. nov.,

Nathorstoceras adnatum gen. et sp. nov., N. kallholnense gen. et sp. nov., Palaeodawsonocerinal

nicolletoides sp. nov., Pleurorthoceras osmundsbergense sp. nov., md Striatocycloceras isbergi sp. nov.

Key words. Katian, Baltoseandia, Nautiloidea, Aseoeerida.

Kroger B. 2013. The cephalopods of the Boda Limestone, Late Ordovician, of Dalarna, Sweden. European Journal

of Taxonomy A\\ 1-110. http://dx.doi.org/10.5852/eit.2013.41

Introduction

The Boda Eimestone eomprises geographieally limited oeeurrenees of massive earbonate bodies in the

Siljan distriet of Dalama, Sweden that are of late Katian to Himantian (Fate Ordovieian) age. The

limestones represent large, up to 150 m thiek and 1000 m wide isolated fossil reefs. The proeesses

responsible for the formation of the reefs, and the physieo-ehemieal eonditions of their depositional

environment remain poorly known, but a eonsensus exists that assumes that the time at whieh these

European Journal of Taxonomy 41: 1-110 (2013)

structures were formed represents an episode of relatively eool elimate - the so ealled Boda Event

(Chems & Wheeley 2007, 2009; Ainsaar et al. 2010). The general absenee of frame builders, sueh as

stromatoporoids, and the omnipresenee of large stromataetis struetures in the mieritie eore faeies make

the Boda reefs textbook examples of earbonate mud mounds (Jaanusson 1982; Suzuki & Bergstrom

1999; Suzuki 2002; Suzuki et al 2009; see Riding 2002 for a definition of a “earbonate mud mound”

and “reef’). Large horizontal and vertieal ereviees and eaves form so ealled “poekets”, filled with

syndepositional eonglomerates and a rieh fauna of eave dwellers and eoneentrated shells (e.g., Suzuki

2002; Rasmussen et al. 2010).

Generally the fauna of the Boda Limestone is highly endemie and very diverse, with more than 90

speeies of trilobites and more than 100 speeies of braehiopods deseribed (see review in Ebbestad &

Hogstrom 2007). The best known are the trilobites (e.g., Warburg 1925), braehiopods (e.g., Coeks

2005; Rasmussen et al. 2010) and bivalves (Isberg 1934). Other groups from the Boda Limestone are

inadequately known taxonomieally and inelude gastropods, eehinodenns, and bryozoans. All are in need

of revision. Herein, for the first time a eomplete deseription of the eephalopod assemblage is presented.

As eephalopods were the top predators in the Late Ordovieian, their taxonomie eomposition, riehness

and body size distribution will eontribute essential data for understanding the Boda eeosystem and may

help to elueidate the eonditions under whieh the mounds formed.

Legend;

□ ^ ^ . I—I Lower Palaeozoic

_ Precambrian 1_| sediments

Towns I I Lakes

O Locality

Fig. 1. Map of the Siljan ring strueture with Lower Palaeozoie sediments preserved (dark grey), and the

three most important loealities are marked (modified from Ebbestad & Hogstrom 2007). Stratigraphieal

seheme of the Boda Limestone and adjaeent lithostratigraphie units (eompiled from Suzuki et al. 2009;

Rasmussen et al. 2010). Abbreviations: Fm = Formation; Mbr = Member; S.S. = stage sliees (after

Bergstrom et al. 2009).

KROGER B., Cephalopods of the Boda Limestone

Cephalopod fossils have been eolleeted from the Boda Limestone for generations, and the Naturhistorisk

Riksmuseet, Stoekholm, Sweden (NRM) and Evolutionsmuseet of the Uppsala University, Uppsala,

Sweden (PMU) hold hundreds of speeimens from most of the important Boda Limestone sites. Seleeted

eephalopod taxa of the Boda Limestone were reported by Angelin & Lindstrom (1880), who deseribed

five speeies, andLrye (1982,1987), who deseribed a number of aseoeerids, oneoeerids and eoiled forms.

Niko (2008) deseribed a single orthoeonie speeies. A eomplete monographie deseription of the museum

material has never been provided. The work presented herein is the first attempt at a monographie

review of the eephalopod assemblage of the Boda Limestone.

This review of the Boda Limestone eephalopods will provide the basis of a eomprehensive stratigraphieal,

palaeobiogeographieal, and palaeoeeologieal analysis of the assemblages. The primary aim of this paper

is to provide a eomplete list of eephalopod oeeurrenees from the Boda Limestone for the first time.

The Boda eephalopods are partieularly rieh in a speeifie group, the Aseoeerida. New aseoeerid speeies

and their features, deseribed herein, provide a new perspeetive on the origin and evolution of this group.

Geological setting

The Boda Limestone oeeurs in more than 20 more or less isolated geologieal bodies around the Siljan

impaet strueture, Dalama, Sweden (see, e.g., Thorslund 1936; Ebbestad & Hogstrom 2007). The

Siljan impaet strueture is an almost eireular geologieal strueture with a diameter of ea. 75 km (Fig. 1).

The strueture is interpreted as the eonsequenee of a mid Devonian meteorite impaet (Reimold et al.

2005). The resulting prominent ring graben of the impaet prevented Lower Palaeozoie sed im ents from

subsequent erosion. The Palaeozoie roeks in the ring graben are teetonieally disturbed, often dipping

strongly, loeally fraetured, and sometimes folded. Nevertheless, the Ordovieian sueeession is remarkably

eomplete and diagenetieally little altered (see review in Ebbestad & Hogstrom 2007).

The stratigraphie sueeession of the Ordovieian of the Siljan distriet has been studied for more than 150

years. A review of the most important Late Ordovieian units was published by Ebbestad & Hogstrom

(2007). The faunal eontent, faeies arehiteeture and ehemostratigraphieal analyses indieate a late Katian-

Himantian age of the Boda Limestone (review in Ebbestad & Hogstrom 2007; Suzuki et al. 2009;

Rasmussen et al. 2010).

The Boda Limestone is eomposed of a late Katian, Boda Core Member (the mound eore faeies), whieh

is eapped by the Himantian Upper Boda Member that undergoes lateral transition to the Boda Flank

Member (Suzuki a/. 2009; Rasmussen a/. 2010;Fig. 1). The Boda Core Member and the Boda Flank

Member of the Boda Limestone are stratigraphieally equivalent to the Johnstorp Formation (Suzuki et

al. 2009). Loeally, the Boda Core Member is overlain uneonformably by the late Himantian Glisstjam

Formation (Rasmussen et al. 2010; Kroger et al. 2011). Often large and eomplex poekets are preserved

within the Boda Core Member (see, e.g., Suzuki 2002). The exaet stratigraphy of the individual poekets

is often difheult to evaluate, but generally the fillings ean be regarded as syndepositional with the Boda

Core Member or the Upper Boda Member (Suzuki et al. 2009, Rasmussen et al. 2010).

Material and Methods

Fossils have been eolleeted and deseribed from the Boda Limestone for nearly two eenturies (see

Ebbestad & Hogstrom 2007 for a review). Historieally, the reefs of the Kullsberg and the Boda

limestones of Dalama are well exposed on small hills and ridges (Warburg 1910). Intensive quarrying

sinee the beginning of the 20* Century ereated new opportunities for stratigraphieal, geologieal and

European Journal of Taxonomy 41: 1-110 (2013)

paleontological investigations and comprehensive collections have been accumulated since then (see

review in Thorslund 1936). The greatest portion of the collections of the Boda Limestone in the NRM

and PMU are mainly the result of the many field excursions carried out by Elsa Warburg (1886-1953)

during the first two decades of the 20* Century to the limestone quarries of the Siljan district. The

collections amassed a total of more than 500 cephalopod specimens. In almost all cases, the specimens

are labelled with a collection date and a locality such as “Osmundsbergef ’ or “Kallholn”, but with

no detailed stratigraphical or locality information (for a detailed listing of the collection localities see

Table 1). The approximate stratigraphical position can be deduced from the matrix lithologies in most

specimens. Two lithologies can be distinguished: (a) a massive whitish wackestone or wackestone-

conglomerate with brownish to reddish mollusk shells, and (b) a pale grey to brownish wackestone,

which is often heavily fractured. The lithologies are interpreted respectively as representing (a) the

latest Katian Boda Core Member and contemporaneous void fillings and pockets, and (b) the Himantian

Upper Boda Member (see Suzuki et al. 2009).

The preservation of shelly material is exceedingly good, with minute details of ornamentation and

even color marks occasionally preserved. However, all cephalopod shells are recrystallised and shell

structures are generally poorly preserved. Often the chambers of the phragmocones are partially empty

or filled with sparite. In one case the chambers are filled with a sequence of a yellowish layered micritic

limestone with bird’s eye structures covered with an ostracod coquina (Fig. 2). A similar concentration

of tiny smooth ostracods in stromatactis cavities of the Boda core facies is reported by Suzuki &

Fig. 2. Polished median section of a fragment of a phragmocone of Geisonoceras wegelini (Angelin in

Angelin & Lindstrom, 1880) comb, nov., PMU 26747, Unskarsheden. The chamber is filled with epi-

and hypsoseptal deposits (a), a layered wackestone with bird’s eye structures (b), a concentration of

ostracods (c) and a sparitic space (d). Picture on the right is detail of picture on the left. Left scale =10

mm, right scale = 1 mm.

KROGER B., Cephalopods of the Boda Limestone

Table 1. List of loealities of Boda Limestone eephalopods with relevant referenees to detailed loeality

deseriptions.

Locality

Coordinates (°N, °E)

Lithostratigraphy

Important references

Kallholn quarry

61.167071,

14.712925

Boda Limestone

Isberg (1934: fig. 1.1); Thorslund (1936: 51, fig. 14); Suzuki et

al. (2009: fig. 1)

Osmundsberget

quarry

61.049173,

15.200615

Boda Limestone

Isberg (1934: fig. 1.7); Thorslund (1936: 46, figs 21-22);

Jaanusson (1982: 35, fig. 4); Ebbestad & Hogstrom (2007: 52,

fig. 53); Suzuki eta/. (2009: fig. 1)

Unskarsheden

quarry

60.948626,

15.103948

Boda Limestone

Isberg (1934: fig. 1.21), Thorslund (1936: 37)

Rattvik

60.895269,

15.109978

Boda Limestone

Warburg (1910: 433, pi. 14)

Skalberget

60.943183,

15.096588

Boda Limestone

Isberg (1934: fig. 1.21); Thorslund (1936: 37, fig. 14);

Jaanusson (1982: 29, figs 2-3)

Ostbjdrka

60.977951,

15.137615

Boda Limestone

Isberg (1934: fig. 1.22); Thorslund (1936: 38, fig. 16)

Amtjam

60.937079,

15.076225

Johnstorp

Formation

Bergstrom (2007: 37, fig. 9); Ebbestad & Hogstrom (2007: 52,

fig. 53)

Jutjarn

60.983085,

15.249453

Boda Limestone

Thorslund (1936: 41); Suzuki & Bergstrom (1999: fig. 1);

Ebbestad & Hogstrom (2007: 58); Suzuki et al. (2009: fig. 1)

Bergstrom (1999) andEbbestad & Hogstrom (2007). Most of the shells are slightly fragmented, partially

broken or slightly deformed as a result of the mid Devonian bolide impaet, but no evidenee of repeated

syndepositional reworking or prolonged exposure or extensive bioerosion is apparent. Therefore, the

material is interpreted as an autoehthonous assemblage representative of the original habitat.

All measurements were taken using vernier ealipers or a ealibrated gratieule inserted into one eyepieee

of a binoeular mieroseope. Unless otherwise indieated, the speeimens were eoated with ammonium

ehloride and then photographed. Polished median seetions of seleeted speeimens were prepared and

photographed. Photographs were made with a Leiea MZ 9.5 stereo mieroseope and a Nikon DS-Fil

eamera enhaneed by Nikon‘s NiS Elements software.

Three deseriptive indiees are used: The whorl expansion rate (WER) adopted from Kom & Klug (2003)

is used for the deseription of eoiled speeimens. The whorl expansion rate is ealeulated as WER =

(d ,/d y where d , is the diameter of the eoneh and d the diameter 360° preeeeding d The whorl

width index (WWl) is the whorl width divided by the whorl height. The siphuneular position ratio (SPR)

is adopted from Frey (1995) and is ealeulated as the minimum distanee of the eonneeting ring from the

eoneh margin divided by the eorresponding eoneh height.

The deseriptive terms eyrtoehoanitie and suborthoehoanitie are often deliberately used; here

“orthoehoanitie” is used strietly when the angle of the septal neek is nearly 90 degrees; “suborthoehoanitie”

is used when it is 90-180 degrees; and “eyrtoehoanitie” when it is more than 180 degrees. This striet

usage in some eases eauses deviations from original speeies or genus diagnoses, whieh are not evaluated

as diagnosis emendations, beeause they regard the terminology only and not the diagnostie eharaeters

themselves.

European Journal of Taxonomy 41: 1-110 (2013)

Results

Phylum Mollusca Linnaeus, 1758

Class Cephalopoda Cuvier, 1797

Order Endoeerida Hyatt in Zittel, 1900

Family Endoeeratidae Hyatt, 1884

Genus Cameroceras Conrad, 1842

Type species

Cameroceras trentonense Comad, 1842, Middleville, New York, USA, Trenton Eimestone, late Katian;

by original designation.

Diagnosis

Slender, large orthoeones with eireular or somewhat depressed eross seetion; sutures simple and straight,

or with very slight ventral lobe; siphunele up to 0.5 of eorresponding eoneh eross seetion in diameter;

mostly marginally positioned; septal neeks holoehoanitie; endoeones simple; endosiphuneular tube

narrow, situated in half of siphunele that is eloser to eoneh margin. (Adopted from Teiehert, 1964.)

Cameroceras hasta (Eiehwald, 1857)

Fig. 3

Endoceras hastadQhsNdXd, 1857: 194.

Rossicoceraspirguense Balashov, 1968: 113, pi. 15, figs 3, 4.

Endoceras - Eiehwald 1860: 1247, pi. 46, fig. 7a-b.

Endoceras megastoma - Teiehert 1930: 270, 273, pi. 5, fig. 1, text-fig. 2 (with synonymy).

Rossicoceras - Balashov 1962: pi. 4, fig. 4; 1968: 112, pi. 15, figs 1, 2; 1974: 794, pi. 4, fig. 4. —

Saladzius 1966: 36, pi. 6, fig. 2. — Dzik 1984: 35, text-fig. 7.32.

Diagnosis

Smooth orthoeones with a slightly depressed eoneh eross seetion; angle of expansion less than 5°;

sutures direetly transverse, ea. seven ehambers oeeur on a distanee similar to the eoneh eross seetion;

siphuneular diameter ea. 0.5 of eorresponding eoneh eross seetion; siphunele slightly removed from

20 40 60 80 100 120 140

conch diameter in mm

20 40 60 80 100 120 140

conch diameter in mm

0.30 0.35 0.40 0.45 0.50

relative sipho diameter

Fig. 3. Variation in relative siphunele size, position and angle of expansion in Cameroceras hasta

(Eiehwald, 1860) (grey points) and Cameroceras turrisoides sp. nov. SPR = the minimum distanee of

the eonneeting ring from the eoneh margin, divided by the eorresponding eoneh height.

KROGER B., Cephalopods of the Boda Limestone

eoneh wall with SPR of 0.1; siphuneular segments slightly eoneave in longitudinal view; septal neeks

holoehoanitie; endosiphoeones form eentral spieulum (eompiled from Balashov 1968).

Type locality and horizon

Saaremoisa, western Estonia, Vormsi Regional Stage, late Katian Ordovieian.

Material examined

Four speeimens (PMU 26609-26612) from Kallholn, Dalama, Boda Limestone; late Katian, Late

Ordovieian.

Description

This speeies was described in detail by Teiehert (1930) and Balashov (1968). The specimen from the

Boda Limestone adds some detail with regard to the variability of some characters. The chamber height

in the four measured specimens varies from ca. 0.1 to 0.2 of the corresponding conch cross section, the

siphuneular diameter varies from 0.42 to 0.5, and the distance of the siphuncle from the conch margin

is 0.09-0.11 of the corresponding conch cross section (Fig. 3). In specimen PMU 26611, parts of the

external shell are preserved, but the preservation is relatively poor and no ornamentation is visible on

the surface.

Remarks

Balashov (1968) distinguished R. pirguense from R. hasta mainly on the position of the siphuncle,

which should be closer to the conch margin in R. pirguense. However, the information given in the

original species description is ambiguous. The measurements provided in the text (Balashov 1968: 113)

reveal a relative distance which is nearly identical to that of R. hasta. Based on these measurements and

the original figures, R. hasta and R. pirguense are indistinguishable and R. pirguense must be regarded

as a junior synonym of R. hasta.

Comparison

Cameroceras turrisoides sp. nov. differs from this species in having a narrower siphuncle (ca. 0.3-0.4

of the corresponding conch cross section) and a siphuncle which is closer to the conch center (SPR ca.

0.2; Fig. 3).

Cameroceras regulus (Eichwald, 1860) from the Vormsi Regional stage of Estonia differs in having a

slightly larger siphuncle (0.5 of conch cross section) in contact with the conch margin. Endoceras coxi

Foerste & Cox, 1936, from the latest Katian of Akpatok Island of the Canadian Arctic, is similar to

C. hasta with respect to the relative diameter of the siphuncle and the relative distance of the siphuncle

from the conch margin. Consequently, this species must be assigned within Cameroceras. The chamber

spacing of Cameroceras coxi (Foerste & Cox, 1936) comb. nov. (ca. 3.6 chambers in a distance

corresponding to the conch diameter) is not within the range of variance of C. hasta.

Stratigraphic and geographic range

Vormsi and Pirgu Regional Stage, Estonia, Lithuania (Saladzius 1966; Balashov 1968), late Katian,

Taymyr, Russia (Balashov 1968); Boda Limestone, late Katian, Siljan District, Sweden.

Cameroceras regulus (Eichwald, 1860)

Endoceras regulus 1857: 111.

Orthoceras turris Angelin Angelin & Lindstrom, 1880: 6, pi. 6, figs 14, 15.

Endoceras iucundum Stumbur, 1956: 182, pi. 25, text-fig. 3, pi. 1, figs 4, 7, 8, pi. 2, figs 1, 3.

European Journal of Taxonomy 41: 1-110 (2013)

Endoceras regulus - Eichwald 1860:1248, pi. 46, fig. 8.

Cameroceras - Balashov 1968: 70, 101, pi. 5, fig. 3.

Diagnosis

Orthocones with a slightly depressed eoneh eross seetion; angle of expansion less than 5°; ornamented

with fine transverse striae; sutures direetly transverse, ea. seven ehambers oeeur on a distanee similar to

the eoneh eross seetion; siphuneular diameter up to 0.5 of eorresponding eoneh eross seetion; siphunele

marginal, in eontaet with shell wall; siphuneular segments slightly eoneave in longitudinal view; septal

neeks holoehoanitie. (Adopted from Balashov 1968.)

Type locality and horizon

Korgesaare, Hiiumaa Island, Estonia; Vormsi Regional Stage, late Katian, Ordovieian.

Material examined

One speeimen (NRM Mo 152350) from Ostbjorka, Dalama, Boda Eimestone; late Katian, Eate

Ordovieian.

Description

The speeimen is a portion of a phragmoeone with a diameter of 72 mm and marginally positioned

siphunele 31 mm in diameter (ea. 0.43 of the eorresponding eoneh eross seetion). Direetly transverse

septa are 18 mm apart (0.25 of the eoneh eross seetion). The eoneh surfaee is ornamented with irregularly

spaeed, widely rounded striae, and in parts a faint, narrowly spaeed shallow longitudinal striation is also

visible.

Remarks

The speeimen deseribed herein was first deseribed and figured as Orthoceras turris Angelin in Angelin

& Eindstrom, 1880; it is the only known speeimen of this speeies. The speeimen agrees in general eoneh

shape and in ornamentation with C. regulus. The speeies C. regulus is based on a type from the Vormsi

Formation, in whieh the shell preservation is poor eompared with that of the Boda Eimestone and faint

details of the ornamentation are not preserved. Therefore, the faint longitudinal striation found in the

speeimen from the Boda Eimestone is regarded here as a eharaeter that does not justify the distinetion

of two speeies, and O. turris is interpreted as a junior synonym of C. regulus.

Comparison

Endoceras landerense Foerste, 1935 is eomparable to Cameroceras regulus with respeet to the angle

of expansion, ehamber height and position and relative diameter of the siphunele, but the details of the

ornamentation of this speeies are not known.

Stratigraphic and geographic range

Vormsi Regional Stage, Estonia (Balashov 1968), late Katian; Boda Eimestone, late Katian, Siljan

Distriet, Sweden.

Cameroceras turrisoides sp. nov.

um:lsid:zoobank.org:aet:3166A3D0-2EBC-40C4-AEF2-F6DFF3152F3Q

Figs 4A, 5, 6, 7D

Endoceras sp. B. - Strand 1934: 10.

Cameroceras sp. - Evans 1994: 16, fig. 6.1-2 (non fig. 6.3).

KROGER B., Cephalopods of the Boda Limestone

Diagnosis

Slender orthoeones with average angle of expansion of ea. 6°, elliptieal eoneh eross seetion, whieh is

slightly eompressed in earlier growth stages and slightly depressed in late growth stages; ornamented with

irregularly spaeed lirae, whieh are slightly oblique, shifted toward the apex on the prosiphuneular side

and forming very shallow, broad hyponomie sinus; additionally shell is slightly irregularly undulated;

sutures direetly transverse, with distanee (eameral depth) varying from 0.17 to 0.3 of the eorresponding

eoneh eross seetion; siphunele eeeentrie with SPR of ea. 0.2; siphunele diameter relatively small with

0.3-0.4 of the eorresponding eoneh eross seetion; siphuneular segments slightly eoneave in longitudinal

seetion, septal neeks holoehoanitie; apex large with angle of expansion of ea. 25°, a length of ea. 50 mm

and a eoneh height of 24 mm, apieally slightly eurved with siphunele on eoneave side of eoneh eurvature.

Etymology

Refers to the similarity of this speeies to the type of Orthoceras turris Angelin in Angelin & Lindstrom,

1880, whieh differs in having a marginal, slightly wider siphunele.

Type material

Holotype

PMU 26613.

Fig. 4. Orthoeonie eephalopods of the Boda Limestone. A. Cameroceras turrisoides sp. nov.,

PMU 26613, holotype, Unskarsheden, lateral view. B. Isorthoceras dalecarlense Kroger et al, 2011,

PMU 26794, Kallholn. C. Isorthoceras wahlenbergi Niko, 2008, PMU 26893 and 26894, Kallholn.

D. Order, gen. et sp. indet., PMU 26950, Kallholn, lateral view. Seale bar =10 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

Paratypes

Fourteen additional speeimens (paratypes): seven (PMU 26614-26620, NRM Mo 9264) from Kallholn;

three (PMU 26621-26623) from Osmundsberget; and four (PMU 26624-26627) from Unskarsheden,

Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian.

Type locality and horizon

Unskarsheden, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is a fragment of a phragmoeone with a length of 128 mm, a eoneh height of 63-77 mm,

and a eoneh width of 68-81 mm (width/height ratio ea. 1.05-1.08, and angle of expansion in width of

ea. 2.2°; Fig. 4A). The eross seetion is elliptieal. The surfaee of the eoneh is ornamented with irregularly

spaeed oblique, shallow lirae. Between the lirae are widely rounded, shallow valleys. The ornamentation

is slightly oblique, forming a shallow broad hyponomie sinus on the prosiphuneular side of the eoneh.

The siphunele of the holotype is eireular in eross seetion with a diameter of 26-31 mm (ea. 0.4 of eoneh

eross seetion) and eeeentrieally positioned with a distanee of 10-12 mm from eoneh margin (SPR ea.

0.16).

A total of 12 measurements reveals a varying angle of expansion with a mean of 5.7°, and a maximum

of 8.8°, without any elear ontogenetie trend, but highest angles oeeur in intermediate eoneh sizes

(Fig. 3). The ehamber distanee was measured in five speeimens and varies between 0.13 and 0.33 of

the eorresponding eoneh eross seetion without any signifieant ontogenetie trend. The diameter of the

siphunele varies between ea. 0.3 and 0.4 relative to the eorresponding eoneh eross seetion diameter.

In general, the initial position of the siphunele is nearly marginal, but during ontogeny shifts toward

the eoneh axis so that the SPR lies between ea. 0.15 and 0.18. However, in the largest speeimen in

Fig. 5. Polished median seetion of Cameroceras turrisoides sp. nov., PMU 26624, Unskarsheden, Boda

Limestone. A. Total fragment; note that the light, layered, mieritie filling of the siphunele is not an

endosiphuneular deposit. B. Enlarged detail of the eonneeting ring and the holoehoanitie septal neek.

Seale bars: A = 10 mm; B = 5 mm.

KROGER B., Cephalopods of the Boda Limestone

the eolleetion (PMU 26627), a portion of phragmoeone has a maximum diameter of 165 mm and a

siphunele diameter approximately 0.3 of the eoneh height, and the SPR is only 0.09.

The strueture of the siphunele ean be seen in speeimen PMU 26624, a pieee of phragmoeone with a

diameter of 75-81 mm (Fig. 5). The septal distanee varies between 8 and 14 mm (nine ehambers oeeur

in a distanee of 97 mm). The septal neeks are holoehoanitie with a eoneave to s-shaped profile.

The eolleetion ineludes two speeimens representing apieal portions (PMU 26623, NRM Mo 9264) with

eompletely preserved shells (Figs 6, 7). Both speeimens possess large eonieal apieal parts (maximum

diameters ea. 25 mm) that differ signifieantly from the younger growth stages. This apieal portion of the

Fig. 6. Apex of Cameroceras turrisoides sp. nov., NRM-PZ Mo 9264, Kallholn, Boda Limestone.

A. View from prosiphuneular side. B. Lateral view. C. Complete speeimen, prosiphuneular view; note

shell repair on adoral part. D. Lateral view. Seale bars: A-B = 10 mm; C-D = 10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Fig. 7. Breviconic cephalopods of the Boda Limestone and details of an endoeerid. A. Dalecarlioceras

constrictum Frye, 1987, PMU 24777, holotype, Kallholn. B. Dalecarlioceras dalecarlicum (Frye,

1987) eomb. nov., PMU 24774, holotype, Kallholn. C. Cyrtorizoceras thorslundi sp. nov., PMU 26658,

Kallholn; note the morphologieal transition between D. constrictum and C. thorslundi sp. nov.; the adult

size inereases in Dalecarlioceras and the mature body ehamber is gibbous. D. Cameroceras turrisoides

sp. nov., PMU 26623, Osmundberget, lateral view of apieal fragment with abrupt transition between

embryonie and juvenile eoneh. E. Strandoceras sphinx (Sehmidt, 1858), PMU 26629, Kallholn. Seale

bars: A-C, E = 10 mm ; D = 10 mm.

KROGER B., Cephalopods of the Boda Limestone

shell is markedly eonieal (apieal angle ea. 25°) and has a eompressed eoneh eross seetion (width/height

ratios of ea. 0.88). The shell surfaee is ornamented with irregular longitudinal grooves and appears

thiekened and irregularly wrinkled around the eireumferenee in a longitudinal direetion. At its adoral

end there is a marked ehange in growth, initiated by a eonstrietion and an abrupt ehange in the angle of

expansion. The eoneh portion 30 mm adorally of the termination of the apieal part of the shell is nearly

tubular and ornamented with the eharaeteristie transverse ornamentation of a more mature speeimen.

This eoneh portion is additionally weakly longitudinally ornamented with irregular striae. The ehange

in growth is aeeompanied by a marked inerease in shell thiekness. In speeimen PMU 26623 the shell

adapieally of the growth ehange is less the 0.5 mm thiek, at the position of the eonstrietion it is only

0.4 mm, and rapidly inereases adorally to ea. 1 mm. The diameter of the siphunele at the position of the

eonstrietion is 9 mm. There the siphunele is nearly marginal, only one millimetre distant from the eoneh

margin.

The apex is eeeentrieally positioned marginally on the prosiphuneular side of the eoneh. The extreme

tip is not preserved, but the slight deerease of the apieal angle at the apiealmost preserved part may

represent the fragment of a subspherieal initial shell (Fig. 6B).

Remarks

The apex of C. turrisoides sp. nov. is exeeptional in form and size, but not entirely unknown. A very

similar apex was deseribed as Endoceras akpatoense Foerste & Cox, 1936, from the latest Katian of

the Aretie Canadian Island Akpatok. This speeimen differs in having even larger dimensions and a less

eurved extreme apieal part. Based on the genus diagnosis of Cameroceras of Teiehert (1964, see above)

this speeies must be reeombined as Cameroceras akpatoense (Foerste & Cox, 1936) eomb. nov.

Comparison

This very large speeies of Cameroceras is most similar to Endoceras windriverense Miller, 1932 (based

on the generie diagnosis of Cameroceras, see above, this speeies must be reeombined as Cameroceras

windriverense (Miller, 1932) eomb. nov.) from the latest Katian Lander Formation from Canada, whieh

has a relative siphunele diameter of 0.35 and an SPR of 0.18, but differs in having a lower angle of

expansion and in having a nearly eireular eoneh eross seetion. Additionally, the ornamentation of this

speeies is not known.

Endoceras sp. B. Strand (1934) is interpreted as eonspeeifie with C. turrisoides sp. nov., even though

the eoneh surfaee of this speeimen is not preserved, beeause it is identieal in having a relatively thin

siphunele (0.4 of eoneh eross seetion), whieh is positioned at a distanee from the eoneh margin (SPR

0.18) whieh is well within the range of the Boda speeimen.

Although the eoneh surfaee is not known in the Cameroceras sp. reported by Evans (1994: fig. 6.1-2)

from the Bardahessaigh Formation of Ireland, it is synonymized with C. turrisoides sp. nov. herein.

This is justified by the size of the siphunele (0.35 of eoneh eross seetion) and the relative distanee of the

siphunele (SPR 0.14), whieh are both within the range of variation of the Boda speeimen.

Stratigraphic and geographic range

Bardahessaigh Formation, mid-late Katian, Ireland (Evans 1994); Bonsnes Formation, Ringerike distriet,

Norway (Strand 1934); Boda Limestone, late Katian, Siljan Distriet, Sweden.

European Journal of Taxonomy 41: 1-110 (2013)

Order Discosorida Flower in Flower & Kummel, 1950

Family Cyrtogomphoeeratidae Flower, 1940

GQxms Kiaeroceras Strand, 1934

Type species

Kiaeroceras frognoyense Strand, 1934, Frognoya, Ringerike, Norway, Sorbakken Formation, late

Katian, Late Ordovieian; by original designation.

Diagnosis

Slender brevieones with ovate eompressed eross seetion; a mature body ehamber with pronouneed

eonstrietion somewhat adapieal of the peristome; aperture with deep and broad hyponomie sinus; sutures

with lateral lobes and pronouneed saddle on prosiphuneular side; siphunele elose to eoneh margin, with

broadly expanded siphuneular segments, with prominent bulletes. (Adopted from Strand 1934.)

Kiaeroceras heroyense Strand, 1934

Fig. 8B-C

Kiaeroceras heroyense Strand, 1934: 99, pi. 9, fig. 5.

Kiaeroceras heroyense - TXosnqx in Flower & Teiehert 1957: 60, text-fig. 17e.

Diagnosis

Kiaeroceras with strongly eompressed eoneh eross seetion with width/height ratio of ea. 0.8. (Adopted

from Strand 1934.)

Type locality and horizon

Heroya, near Porsgrunn, Norway; Heroya Formation (“Gastropod Limestone”), late Katian, Late

Ordovieian.

Material examined

PMU 26628 from Kallholn, Dalama, Sweden; Boda Limestone, Upper Boda Member, Himantian, Late

Ordovieian.

Description

The speeimen is a fragment of parts of the phragmoeone and the body ehamber of a mature individual

(Fig. 8B, C). The eoneh is straight with a eompressed eross seetion. At the base of the body ehamber

the maximum diameter is reaehed, with a height of 68 mm and a width of 55 mm (width/height ratio

0.81). At a position ea. 40 mm in apieal direetion, the eoneh height is 55 mm (angle of expansion, 18°).

The preserved part of the body ehamber is ea. 50 mm long. The eoneh surfaee is smooth with faint

growth lines. The outer shell is relatively thiek with ea. 1.5 mm at the base of the body ehamber. The

sutures form shallow lateral lobes, their distanee is ea. 7 mm where the eoneh height is 60 mm (0.12 of

eorresponding eoneh height). The septa are shallowly eonvex with eonvexity of ea. 0.1 of eorresponding

eoneh height. The siphunele is marginal with a diameter of ea. 0.15 of the eorresponding eoneh eross

seetion. The siphuneular segments are strongly expanded within the ehambers.

KROGER B., Cephalopods of the Boda Limestone

Remarks

The speeimen from the Boda Limestone is nearly identieal in dimensions, septal eonvexity and ehamber

spaeing to Kiaeroceras frognoyense Strand, 1934. However, Strand (1934) distinguished the two speeies

of Kiaeroceras based on the shape of the eoneh eross seetion. As the width/height ratio of the eoneh of

speeimen PMU 26628 is 0.81, it is more similar to K. heroyense than to K. frognoyense (with a width/

height ratio of 0.87), with a less eompressed eoneh (Strand 1934: 97).

Kiaeroceras frognoyense and K. heroyense probably represent a eontinuous speetmm of morphologieal

variation or sexual dimorphs. Given the paueity of known material, sueh speeulation eannot be tested

and the original speeies diagnoses of Strand (1934) are aeeepted herein.

The speeimen, deseribed above, is the most eomplete speeimen known from this genus with regard to

the phragmoeone. It displays a eurved lateral outline of both the pro- and antisiphuneular eoneh margin,

an oval eoneh eross seetion and details of the shell surfaee.

Stratigraphic and geographic range

Heroya Formation, Norway (Strand 1934); Boda Limestone, Upper Boda Member, Himantian, Dalama,

Sweden; all late Katian-Himantian.

Fig. 8. Orthoeonie brevieones of the Boda Limestone of Kallholn. A. Tyrioceras ef kjaerulfi Strand,

1934, PMU 26897, view from antisiphuneular side. B-C. Kiaeroceras heroyense Strand, 1934,

PMU 26628. B. Lateral view, with siphunele on left side. C. View from antisiphuneular side. Seale bar

= 10 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

Genus Strandoceras Flower, 1946

Type species

Protophragmoceras tyriense Strand, 1934, Stavnestangen, Ringerike, Norway, Gastropod Limestone,

late Katian, Late Ordovieian; by original designation.

Diagnosis

Strongly eompressed eyrtoeones with narrowly rounded venter; in eoneh eross seetion shallow

longitudinal furrow at left and right flank in direet vieinity of siphunele; siphunele elose to eoneave

margin of eoneh; sutures with shallow lateral lobe and aeute ventral saddle; septal neeks are short

eyrtoehoanitie; eonneeting ring thiek, strongly expanded within ehambers; aperture is open with shallow

peristomal saddle at flank. (Adopted from Kroger 2007.)

Strandoceras sphinx (Sehmidt, 1858)

Fig. 7E

Phragmoceras sphynx Sehmidt, 1858: 200.

Protophragmoceras sphinx - Teiehert 1930: 270, 299-301, pi. 7, flg. 20, pi. 8, flg. 24, text-flgs 3, 4. —

Dzik 1984: 48, 52, 65, text-flg.14.5, pi. 7, flg. 7.

Protophragmoceras sphynx - Strand 1934: 93.

Strandoceras sphynx -TXowqx in Flower & Teiehert 1957: 57, 114, text-flgs 15e, g-h.

Strandoceras sphinx - ^dXdiS\\OY 1975: 69, pi. 2, flg. 1.

Diagnosis

Strandoceras with moderate eurvature, angle of expansion 16-19°; eompressed eoneh eross seetion

with width/height ratio of 0.8-0.9; body ehamber long, reaehing 0.4 of total eoneh length; ornamented

with distinetive transverse rounded striae, whieh form shallow sinuses on the anti- and prosiphuneular

side of the eoneh. (Adopted from Strand 1934 and Dzik 1984.)

Type locality and horizon

“Setlep”, Island Vormsi, Estonia, Vormsi/Pirgu Regional Stage (“Eyekholm stage”, Teiehert 1930), late

Katian, Ordovieian.

Material examined

Three speeimens (PMU 26629-26631) Ifom Kallholn, Dalama, Boda Eimestone; one speeimen (PMU

26632) from Amtjam, Dalama, Johnstorp Formation. All late Katian, Eate Ordovieian.

Description

The largest speeimen, PMU 26629, is a pieee of phragmoeone, measuring 74^8 mm in height, and with

a maximum width of 63 mm (width/height ratio 0.85) and expanding at an angle of 19° (Fig. 7E). The

eoneh eross seetion is broadly rounded on the antisiphuneular side and forms a eharaeteristie narrow

subangular margin on the prosiphuneular side. Adorally the siphunele measures ea. 6 mm in diameter

(0.08 of eoneh height) and is almost marginal in position on the eoneave side of the eoneh. The septa

are narrowly spaeed at a distanee of ea. 8 mm (ea. 0.11 of eorresponding eoneh height) in the adoral

part of the fragment. The sutures are direetly transverse. The eoneh surfaee is ornamented with flne,

relatively widely spaeed rounded transverse striae, distanee between striae is ea. 3 mm at the adoral part

of the fragment. The striae form a broadly eurved lateral salient and shallow sinuses on the pro-, and

antisiphuneular sides.

KROGER B., Cephalopods of the Boda Limestone

A seeond speeimen, PMU 26631, eonsists of a portion of phragmoeone with a eoneh height of 16 mm

apieally. Shallow rounded striae ea. 0.7 mm in width are displayed on the apieal part of the phragmoeone.

These are almost direetly transverse, but form shallow sinuses on the the pro-, and antisiphuneular sides

of the eoneh.

Remarks

The speeimens from the Boda Limestone are very similar to the speeimen deseribed and figured from

the Vormsi/Pirgu Regional Stage of Estonia (“Lyekholm stage” of Teiehert 1930: pi. 8, fig. 24) whieh

has a width/height ratio of the eoneh of 0.76, an apieal angle of ea. 16° and a similar ornamentation and

eurvature.

Comparison

S. strandi Sweet, 1958 differs from S. sphinx in its more eompressed eoneh eross seetion (width/height

= 0.68). S. tyriense differs from S. sphinx in its smaller adult size (ea. 60 mm eoneh height) and stronger

eurvature of the eoneh.

Stratigraphic and geographic range

Upper Heroya Formation (“Gastropod Limestone”), Skien-Langesund distriet, Norway (Strand 1934);

erratie limestone boulders from Vormsi/Pirgu Regional Stage, Zgierz, Poland (Dzik 1984); Vormsi/Pirgu

Regional Stage (“Lyekholm stage”), Estonia (Teiehert 1930); Molodov Horizon, Podolia (Balashov

1975); Johnstorp Formation (“Grey Tretaspis Shale”), Boda Limestone, Dalama, Sweden; all late Katian.

Order Oneoeerida Flower in Flower & Kummel, 1950

Family Oneoeeratidae Flower in Flower & Kummel, 1950

Genus Beloitoceras Foerste, 1924

Type species

Oncoceras pandionHaW, 1861, Blaek River Formation, Beloit, Wiseonsin, USA; by original designation.

Diagnosis

Strongly eurved, relatively slender brevieones with ovate, eompressed eross seetion. Coneh smooth

or with fine transverse ornament. Maximum eoneh diameter situated within adapieal half to third of

body ehamber. Antisiphuneular outline of eoneh eoneave over entire length in longitudinal seetion,

prosiphuneular outline broadly eonvex. Five to eight ehambers per distanee similar to eorresponding

eoneh eross seetion. Body ehamber short with well developed hyponomie sinus at eonvex side. Siphunele

slender, situated elose to eonvex margin of eoneh eurvature, with subtubular segments. Septal neeks

short suborthoehoanitie to eyrtoehoanitie. Conneeting rings thin. (Compiled from Sweet 1964b and Frey

1995.)

Beloitoceras sinuososeptatum (Roemer, 1861)

Figs 9A-B, 11

Orthoceras sinuososeptatum Roemer, 1861: pi. 6, fig. 3a-e.

Beloitoceras heterocurvatum Strand, 1934: 76, pi. 10, figs 8-9.

Richardsonoceras sinuososeptatum-Dzik 1984: 188, text-fig. 16a-b, pi. 8, fig. la-d.

Beloitoceras heterocurvatum -¥rye 1987: 84, figs 3a-d. — Kroger et al. 2011: 38, fig. 5a-b.

European Journal of Taxonomy 41: 1-110 (2013)

Emended diagnosis

Beloitoceras with compressed eross seetion with keeled eoneh margins at eoneave and eonvex side of

eoneh eurvature throughout entire length; in longitudinal seetion antisiphuneular eoneh margin eoneave;

angle of expansion of phragmoeone ea. 16-17°; depth of body ehamber somewhat less than maximum

eoneh height; eoneh surfaee ornamented with irregularly spaeed rounded striae, whieh form a shallow

sinus on prosiphuneular side and deep v-shaped sinus on antisiphuneular side; about six ehambers

Fig. 9. Oneerida of the Boda Limestone. Note the high variability in eoneh eurvature and angle of

expansion in Beloitoceras. A-B. Beloitoceras sinuososeptatum (Roemer, 1861). A. PMU 24769.

B. PMU 26638, Kallholn. C-D. Beloitoceras siljanense Frye, 1987. C. PMU 26644. D. PMU 26645,

Kallholn. E-F. Apex of Beloitoceras sp., PMU 26646, Kallholn. E. Adapieal view. F. Lateral view.

G-H. Cyrtorizoceras thorslundi sp. nov., PMU 26657, Osmundsberget, mature body ehamber. G. Lateral

view. H. Adapieal view. I. Beloitoceras siljanense Frye, 1987, PMU 26643, Kallholn, with major eoneh

repair at adoral part. J. Cyrtorizoceras thorslundi sp. nov., PMU 26647, holotype, Kallholn, eomplete

juvenile speeimen. Seale bars: A-D, G-J =10 mm; E-F = 2 mm.

KROGER B., Cephalopods of the Boda Limestone

similar to the height of the eoneh eross seetion; sutures with deep lateral lobes; siphunele situated near

ventral margin, segments ea. twiee as high as wide, with slightly eonvex vertieal outline.

Type locality and horizon

Zawidowiee near Olesniea, Poland, erratie boulder of probably latest Katian age, Ordovieian.

Material examined

Thirteen speeimens in total: PMU 26633-26642, 24769, 24772, Kallholn, Dalama; one speeimen

(PMU 24770), Skalberget, Dalama, Boda Limestone, late Katian.

Description

The general features of the eoneh, the ornamentation and the details of the siphunele were deseribed

by Strand (1934), Dzik (1984) and Frye (1987). These deseriptions were based on relatively few

speeimens. Here, 15 additional speeimens are available for measurements and direet eomparison. These

speeimens reveal a high variability in eoneh eurvature and angle of expansion. The eoneh eurvature

varies from strongly eurved to relatively widely eurved (Fig. 9A-B). The angle of expansion varies from

15° (L^ quantile) to, 18° (3'^^ quantile) with a mean of 17° (15 measurements) in the speeimens from

the Boda Limestone. The eoneh eross seetion is always eompressed with a typieal keel at the anti-, and

prosiphuneular side, but the rate of eompression varies among the Boda Limestone speeimens from 0.85

(L^ quantile) to 0.92 (3"^^ quantile) with a mean of 0.87 (10 measurements). Within this range of varianee

no distinet groups of speeimens ean be distinguished (Fig. 11).

Remarks

In earlier deseriptions the variability of the eoneh shape of this speeies was not reeognized. Additionally,

the adult size of different speeimen assigned to this speeies varies from 28 to 38 mm maximum body

ehamber height. Beeause only three speeimens from the Boda Limestone possess an adult body ehamber

(speeimen figured in Frye 1987: fig. 3a, b; PMU 24769, 26634), it is impossible to evaluate whether this

differenee refieets interspeeifie variability, sexual dimorphism or the presenee of more than one speeies.

The type speeimen from Vormsi/Pirgu Regional Stage limestones of the erratie boulders of northern

Poland, figured by Dzik (1984, pi. 8, fig. la-d), differs from the Boda Limestone speeimens in its

exeeptionally low angle of expansion of only 10°. Moreover, the paratype figured by Dzik (1984), with a

width/height ratio of 0.72, and the speeimen from the Oslo area figured by Strand (1934: pi. 10, fig. 8) are

eonsiderably more eompressed than the speeimens from the Boda Limestone. Also, these two speeimens

represent the lower range of the angle of expansion for all the speeimens measured (Fig. 11). However,

based on the available information it is impossible to distinguish different speeies of Beloitoceras among

the speeimens figured and deseribed by Dzik (1984: pi. 8, fig. la-d). Strand (1934), Frye (1987: fig. 3a,

b) and the material deseribed herein. Based on the available material, B. sinuososeptatum is eonsidered

a speeies of Beloitoceras with a highly variable eoneh eurvature, high varianee in the angle of expansion

(Fig. 11), and potentially eneompasses maero-, and mieroeoneh varieties.

An apieal fragment, PMU 26646, is interpreted as Beloitoceras sp. (Fig. 9E-F), beeause of its similarity

in general eoneh shape and ornamentation with the larger fragments. The apex is eup-shaped and reaehes

a eoneh height of 4.3 mm and a width of 4 mm at a distanee of 2 mm from the tip. The shell of this

speeimen is ornamented with fine rounded transverse annuli (ea. 8-10 per millimetre), whieh form a

shallow hyponomie sinus on the eoneave side of the eurved eoneh.

European Journal of Taxonomy 41: 1-110 (2013)

Comparison

Two groups of Beloitoceras are distinguishable within the Boda Limestone. Aeeording to Frye (1987),

B. siljanense Frye, 1987 ean be distinguished from B. sinuososeptatum in having an antisiphuneular

eoneh margin that straightens relatively early during growth and remains straight in the mature body

ehamber. By eontrast, in B. sinuososeptatum the antisiphuneular eoneh margin is entirely eurved along

the entire length of the eoneave side of the eoneh. It was emphasized above that the eoneh eurvature and

angle of expansion vary strongly between speeimens of Beloitoceras from the Boda Limestone. Within

this eontinuous speetrum of variation, the types of both speeies represent two extremes with a maximum

eoneh expansion in B. siljanense Frye, 1987 (23°) and a minimum in B. sinuososeptatum (10°). Based

on the angle of expansion alone, it is not possible to distinguish between the two speeies (Fig. 11).

B. siljanense may be distinguished from B. sinuososeptatum in having a finer transverse ornamentation

and a less eurved antisiphuneular eoneh margin (eompare Fig. 9A-B, C-D).

Beloitoceras landerense Foerste, 1935 from the mid Katian Lander Sandstone of Wyoming, USA is

very similar to B. sinuososeptatum in general eoneh shape and dimensions (Fig. 11). As the details

of the ornamentation of this speeies are not known, direet eomparison and synonymisation with B.

sinuososeptatum is not possible at present.

Beloitoceras whitneyi (Hall, 1861) from the Elgin Formation, late Katian, Iowa, USA is similar to

B. sinuososeptatum in general eoneh shape, its transversely ornamented shell, and in possessing a

relatively large adult eoneh height of ea. 35 mm. It may be eonspeeifie with the Boda speeimens, but

with ea. 9-10 ehambers in a length similar to the eorresponding eoneh height, the ehamber distanee

(eameral depth) is signifieantly lower in Beloitoceras whitneyi than that of B. sinuososeptatum (six

ehambers per length similar to eorresponding eoneh height) and nothing is known about the variability

of this eharaeter in either speeies. A synonymisation of this speeies is very likely, but may only be

possible to demonstrate after eomparison of the variability of the ehamber height in both assemblages.

Stratigraphic and geographic range

Bonsnes Formation, Ringerike district, Skogerholm Formation, Oslo-Asker district, Norway (Strand

1934); erratic limestone boulders from Vormsi/Pirgu Regional Stage (“Lyckholm stage”), Zawidowice,

Poland (Dzik 1984); Vormsi/Pirgu Regional Stage (“Lyckholm stage”), Estonia (Teichert 1930); Boda

Eimestone, Dalama, Sweden; all late Katian.

Genus Cyrtorizoceras Hyatt in Zittel, 1900

Type species

Cyrtoceras minneapolis Clarke, 1897, Minneapolis, Minnesota, USA, Platteville Formation, early to

mid Katian, Eate Ordovician; by original designation.

Diagnosis

Compressed cyrtocones with conchs expanding constantly on anti- and prosiphuncular side; body

chamber slightly contracted; aperture with deep hyponomic sinus; surface ornamented with obscure

or prominent transverse costae; siphuncle close to conch margin on convex side of conch curvature,

slender; siphuncular segments slightly expanded, probably empty. (Adopted from Sweet 1964a.)

Comparison

Cyrtorizoceras is similar to Richardsonoceras Foerste, 1932 in having a gradually enlarging cyrtoconic

conch with a curved mature body chamber. Cyrtorizoceras differs from Richardsonoceras in having

KROGER B., Cephalopods of the Boda Limestone

a generally less eurved eoneh, higher angles of expansion and a mature body ehamber with a more

pronouneed, angular sinus on the prosiphuneular side of the mature body ehamber.

Remarks

This is a speeies rieh genus with more than 35 speeies deseribed, mostly known from the Late Ordovieian

of North Ameriea. The genus is in need of revision, as it probably eneompasses several distinet and

perhaps distantly related groups of eyrtoeonie oneoeeratids, all possessing a simple, non gibbous body

ehamber.

Cyrtorizoceras thorslundi sp. nov.

um:lsid:zoobank.org:aet:3B69DD96-EQF9-4516-9383-6DC8FL7D0BFD

Figs 7C, 9G-H, J, lOA

Diagnosis

Cyrtorizoceras with adult body ehamber height of ea. 35 mm and angle of expansion of 12-13°; eoneh

eross seetion eompressed, ovate, with slightly angular anti- and prosiphuneular margins and with width/

Fig. 10. Camera lueida drawings of eross seetions of seleeted Boda Limestone eephalopods.

A. Cyrtorizoceras thorslundi sp. nov., PMU 26657, Osmundsberget, mature body ehamber. B. Tyrioceras

ef kjaerulfi Strand, 1934, PMU 26897, Kallholn. C. Nathorstoceras adnatum sp. nov., PMU 26733,

holotype, Kallholn. D. Nathorstoceras kallholnense sp. nov., PMU 26729, holotype. E. Redpathoceras

depressum sp. nov., PMU 26927, holotype, Kallholn, eross seetion of base of mature truneated eoneh.

F. Schuchertoceras fryi sp. nov., PMU 24744, holotype, Kalllholn, eross seetion of mature aperture (dark

grey) and body ehamber (medium grey). G. Redpathoceras bullatum sp. nov., PMU 26923, holotype,

Kallholn, eross seetion of base of mature truneated eoneh. Prosiphuneular side direeted downward in all

figures. Siphuneles shown as white eireles. Seale bar =10 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

height ratio of ca. 0.8-0.9; ornamented with fine, rounded, direetly transverse striae; adult body ehamber

length 30 mm with angle of expansion similar to premature eoneh, shallow eonstrietion and adoral

widening at adult peristome; shallow angular sinus at prosiphuneular side; mature portions of eoneh

slightly less eoiled than adapieal parts; apex large, eap-shaped.

Etymology

In honour of Per Thorslund (1900-1991), Swedish geologist and paleontologist and professor at

Uppsala University (1950-1966), for his important eontributions on the geology of the Siljian region

(e.g., Thorslund 1935).

Type material

Holotype

PMU 26647.

Paratypes

Twelve additional speeimens (paratypes): PMU 26648-26659 from Kallholn, Dalama, Sweden, Boda

Limestone, Boda Core Member, late Katian.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is a eomplete juvenile speeimen with a eoneh length of ea. 40 mm, maximum eoneh width

at peristome 11 mm, eoneh height 13 mm, a ea. 15 mm long body ehamber and a nearly eomplete apieal

portion (Fig. 9J). Apieally the eoneh grows from the absolute tip toward a eoneh height of 4 mm within

the first 2 mm. The eoneh surfaee of the holotype is ornamented with rounded striae, whieh mn straight

and form a shallow sinus at the prosiphuneular side; ea. five oeeur per one millimeter at the adoral parts

of the eoneh.

In speeimen PMU 26648, whieh is a fragment of the phragmoeone, the septa and the siphunele are

exposed. The septa are simply eurved, and the sutures form shallow lateral lobes 1.9 mm distant where

■(D

-Q —

O LO

O CD

OOU

■“ CM

o ^

C CM

E 00

O O ^ o O

O O #

O O ^

CO ^ ~

X —

^ o *

qO 8 OO O

^ _

O O o o o ^

0) —

^^^ #

ing

_,_,_,__Q_,__

15 20 25 30 35

conch height in mm

15 20 25 30 35

conch height in mm

Fig. \\.Movfho\ogicdi\\diXiditionofBeloitocerassinuososeptatum (KoQmQX, 1861). Circles: specimens of

the Boda Limestone. Black dot: type specimen of Beloitoceras siljanense Frye, 1987. Black diamonds:

types of Beloitoceras heterocurvatum Strand, 1934. Grey dot: type specimen of Beloitoceras landerense

Foerste, 1935. A distinction between B. siljanense and B. sinuososeptatum is impossible based on the

available material.

KROGER B., Cephalopods of the Boda Limestone

the eorresponding eoneh height is 10.5 mm (0.18 of eorresponding eoneh height). The siphunele is nearly,

but not exaetly marginal, its width is 0.6 mm at a eorresponding eoneh height of 6.6 mm (ea. 0.9 of eoneh

height). The siphuneular segments are slightly expanded and the eonneeting ring is eomparatively thin.

The angle of expansion varies only very little among the eight speeimens, with 11.5° (PMU 26649) to

13.3° (holotype).

The adult eoneh height of 34 mm and width 28 mm is indieated by three body ehambers of s im ilar

size with distinet peristomal shell thiekenings (PMU 26656, 26657, 26659; Figs 9G-H, lOA). These

fragments of the body ehambers are ornamented with fine transverse striae that form a distinet shallow

sinus at the prosiphuneular side. The striae are ea. 1 mm wide.

Remarks

The material deseribed above eonsists of eight juvenile speeimens and three adult body ehambers. No

fragments of intermediate growth stages are known. The fragments are assigned to Cyrtorizoceras

thorslundi sp. nov. beeause they have a similar eoneh eurvature and nearly identieal angles of expansion,

eross seetion shapes and ornamentation.

Comparison

This speeies differs from the type of the genus in having a more slender body ehamber, a less pronouneed

ornamentation and a shallower eoneh eurvature. Cyrtorizoceras thorslundi sp. nov. is unique amongst

the other speeies assigned to the genus in its eombination of a fine transverse ornamentation with a

relatively weak eoneh eurvature.

The poorly preserved fragment, deseribed by Teiehert (1930) as Beloitoceras (?) estonicum from the

Pirgu Regional Stage of Hosholm, Estonia, is very similar to C. thorslundi sp. nov. in general eoneh

shape and should very probably be synonymised with the latter. However, better preserved material is

needed for a definitive eomparison.

The small C. tenue Strand, 1934 from the Gastropod Limestone of the Oslo region is very similar to

C. thorslundi sp. nov. with respeet to the general eoneh shape, size and ornamentation. However, in

C. tenue the angle of expansion is eonsiderably higher (ea. 17°), and the eoneh is more strongly eurved.

The juvenile speeimens of C. thorslundi sp. nov. ean be distinguished from speeimens of Beloitoceras

in the Boda limestone by its broader eoneh eurvature and low angle of expansion.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Genus Dalecarlioceras Frye, 1987

Type species

Dalecarlioceras bodense Frye, 1987, Kallholn, Dalama, Sweden, Boda Limestone, late Katian, Late

Ordovieian; by original designation.

Diagnosis

Cyrtoeones with moderate to large angle of expansion, eompressed eoneh eross seetions; eoneh eurved

with siphunele elose to eoneh margin on eonvex side of eoneh eurvature; body ehamber gibbous with

European Journal of Taxonomy 41: 1-110 (2013)

maximum gibbosity at mid-length, becoming compressed orad with profile on antispihuncular side

faintly concave, moderately convex on prosiphuncular side; aperture may be constricted with prominent

hyponomic sinus; siphuncle small in diameter with tubular, somewhat expanded segments that are

empty. (Adopted from Frye 1987.)

Dalecarlioceras dalecarlicum (Frye, 1987) comb. nov.

Fig. 7B

Cyrtorizoceras dalecarlicum Frye, 1987: 88, 89, fig. 6d-f

Emended diagnosis

Dalecarlioceras with slightly curved adult body chamber, with maximum adult height/width of ca.

40/38 mm, and adult peristome height/width 37/33.

Holotype

PMU 24774.

Type locality and horizon

Kallholn, Siljan District, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovician.

Other material examined

One specimen (PMU 24775) from Kallholn, Dalama; one specimen from Rattvik, Dalama, NRM Mo

150043, Boda Limestone, Boda Core Member, late Katian.

Description

See Frye (1987: 88-89) for a detailed description.

Remarks

Dalecarlioceras is endemic to the Boda Limestone. Originally, two species were assigned to this genus:

the large D. bodense, characterized by a high angle of expansion, and the somewhat smaller, more

slender D. constrictum Frye, 1987 (Fig. 7A). Herein, the medium sized Cyrtorizoceras dalecarlicum

Frye, 1987 is considered an additional species of Dalecarlioceras. Dalecarlioceras dalecarlicum (Frye,

1987) comb. nov. has an only slightly curved adult body chamber, combined with a slightly irregularly

spaced ornamentation with transverse growth lines similar to those of D. bodense. The mature body

chamber of D. dalecarlicum comb. nov. differs from that of Cyrtorizoceras in having a nearly straight,

or slightly concave outline in lateral view (Fig. 7B-C); it is clearly compressed at the aperture in frontal

view. Consequently, the body chamber of D. dalecarlicum comb. nov. is widest approximately at

mid-length, like in D. bodense. D. dalecarlicum comb. nov. is considered to represent a transitional

form between D. constrictum and Cyrtorizoceras thorslundi sp. nov. Together these forms represent

a transition from the relatively small and slender C. thorslundi sp. nov., with a weakly gibbous body

chamber, toward the massive, and strongly gibbous D. bodense. This suggests an ancestry or close

relationship of Dalecarlioceras to Cyrtorizoceras.

Stratigraphic and geographic range

Boda Limestone, Dalama, Sweden; late Katian.

KROGER B., Cephalopods of the Boda Limestone

Order Orthoeerida Kuhn, 1940

Suborder Orthoeeratina Kuhn, 1940

Family Orthoeeratidae MeCoy, 1844

Genus Striatocycloceras Kroger & Isakar, 2006

Type species

Orthoceras undulostriatum Hall, 1847 from the Trenton Formation, late Katian of Middleville, New

York, USA.

Diagnosis

Slender, eireular or slightly eompressed orthoeones with asymmetrieally eurved septa and straight

transverse or slightly oblique sutures. Sutures parallel, or nearly so, to the annulations; annulations

slightly irregularly spaeed, with fine transverse ornament; siphunele eeeentrie, narrow, tubular or slightly

expanded within the ehambers; septal neeks orthoehoanitie. Cameral and endosiphuneular deposits not

known.

Remarks

The eaptions of the figures of the speeies of Striatocycloceras in Kroger & Isakar (2006) are erroneous

and misleading. The errors must be eorreeted as follows: Striatocycloceras obliquum (Teiehert, 1930) is

figured in Kroger & Isakar (2006: figs 7k, o, 8d, 11), as eorreetly stated in the text, and Striatocycloceras

undulostriatum (Hall, 1847) is also eorreetly figured (Kroger & Isakar 2006: figs 71 8e, 10a); other

speeies shown are Striatocycloceras romingeri (Foerste, 1932) (Kroger & Isakar 2006: figs 7p, 8r-t) and

Striatocycloceras foerstei (Teiehert, 1930) Kroger & Isakar (2006: figs 7q, lOh).

Comparison

Striatocycloceras is similar in ornamentation and eoneh shape to the dawsonoeeratid Anaspyroceras

Shimizu & Obata, 1935, whieh differs in having short, nearly aehoanitie septal neeks.

Striatocycloceras isbergi sp. nov.

um:lsid:zoobank.org:aet:23541702-00D8-4063-AE65-6799DE63E2AD

Figs 12B-C, 13B-C, 14A

Striatocycloceras foerstei - Kroger & Isakar 2006: 151, figs 7q, lOh.

Diagnosis

Slender orthoeones with apieal angle less than 10° and eoneh eross seetion less than 15 mm at maturity;

ornamented with eight to ten pronouneed, sharply erested annuli at distanee equal to eorresponding

eoneh diameter; annuli laterally oblique ea. 70° to growth axis; ea. three annuli in distanee between

septa; siphunele slightly subeentral; nearly tubular segments; septal neeks orthoehoanitie.

Etymology

In honor of Orvar Isberg (1884-1950), a Swedish paleontologist who published an extensive monograph

on the Boda Limestone bivalves (Isberg 1934).

Type material

Holotype

PMU 26660.

European Journal of Taxonomy 41: 1-110 (2013)

Paratypes

Thirty-seven paratypes: one speeimen (PMU 26661) from Osmundsberget; 36 speeimens (PMU 26662-

26698), Kallholn, Siljan Distriet, Sweden; all Boda Limestone, Boda Core Member, late Katian.

Type locality and horizon

Kallholn, Siljan Distriet, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

Holotype is a 45 mm long, 10-13 mm wide portion of phragmoeone (angle of expansion 4°) with a

eireular eoneh eross seetion (Fig. 12B). The shell surfaee is ornamented with sharply erested annuli, of

whieh ea. eight oeeur at a length equal to the eoneh diameter. The annuli form sharp, angular erests with

Fig. 12. Annelate Orthoeerida of the Boda Limestone. A. Palaeodawsonocerina senckenbergi (Teiehert,

1930), PMU 26718, Kallholn. B-C. Striatocycloceras isbergi sp. nov., Osmundsberget. B. PMU 26660,

holotype, Osmundberget. C. PMU 26664. D-E. Palaeodawsonocerina? nicolletoides sp. nov., PMU

26728, Kallholn. D. Adapieal view. E. Lateral view. Seale A-C =10 mm; D-E = 10 mm.

KROGER B., Cephalopods of the Boda Limestone

Fig. 13. Polished median seetions of Orthoeerida of the Boda Limestone. A. Dawsonoceras fenestratum

(Eiehwald, 1860), PMU 26706, Kallholn. B-C. Striatocycloceras isbergi sp. nov. B. PMU 26681,

Kallholn. C. PMU 26661, Osmundsberget. D. Isorthoceras angelini sp. nov., PMU 26784, Kallholn.

E. Nathorstoceras kallholnense sp. nov., PMU 26729, holotype, Kallholn. F. Nathorstoceras adnatum

sp. nov., PMU 26733, holotype, Kallholn. G. Pleurorthoceras osmundsbergense sp. nov., NRM-PZ Mo,

190102e, Osmundsberget. H. Ordogeisonocerasfoerstei (Strand, 1934) eomb. nov., PMU26763, Kallholn.

I. Geisonoceras wegelini (Angelin />? Angelin & Lindstrom, 1880) eomb. nov., PMU 26740, Kallholn.

Seale bars: A-D, 1=1 mm; E-H = 5 mm.

European Journal of Taxonomy 41: 1-110 (2013)

wide, rounded grooves. The shell surfaee is otherwise nearly smooth, with only very faint transverse

growth lines visible. The annuli are oblique, at ea. 70° to the growth axis. In speeimen PMU 26661 the

sutures are direetly transverse and erossed obliquely by the annulations. The septa are markedly eonvex,

being 3 mm deep at a eoneh diameter of 7 mm (0.43 of eoneh diameter). The siphunele is eentrally

positioned, with a septal perforation of 0.9 mm at a diameter of 7 mm (0.13 of eoneh diameter).

The juvenile speeimen, PMU 26664, has a diameter of 2.2-3 mm and a length of 13 mm (angle of

expansion is slightly eurved and less pronouneedly annulated; Fig. 12C).

The internal eharaeters are well preserved in speeimen PMU 26681 (Figs 13B, 14A), whieh is aportion of

a phragmoeone with a diameter inereasing from 7.5 to 9 mm and a length of 16 mm. The ehamber height

at the adoral end of this fragment is 3 mm (0.3 of eorresponding eoneh diameter), and the distanee of

the siphunele is 3.8 mm (SPR 0.42). In speeimen PMU 26661 the siphunele is relatively well-preserved.

There the siphunele is nearly tubular and the septal neeks are orthoehoanitie (Fig. 13C).

Remarks

The larger number of speeimens at the PMU permit an evaluation of eoneh variability and an estimation

of the adult size of this speeies. Based on these new data, the speeimen figured in Kroger & Isakar

(2006: figs 7q, lOh) from the Vormsi Regional Stage of Hiiumaa Island, Estonia, must be assigned to

Striatocycloceras isbergi sp. nov. It differs from the type speeimen of S.foerstei in its smaller size and

its more numerous, more sharply erested annuli. In this, it lies within within the range of variability of

the speeimens of S. isbergi sp. nov. from the Boda Limestone.

Comparison

This speeies is unique with regard to its narrow annulation. The otherwise similar S. foerstei differs in

having six to seven annulations per distanee equal to eoneh diameter and a signifieantly larger adult size.

Stratigraphic and geographic range

Vormsi Regional Stages, Estonia (Kroger & Isakar 2006); Boda Limestone, Siljan Distriet, Sweden, late

Katian, Ordovieian.

A B CD

Fig. 14. Reeonstruetions of the details of the septal neeks and siphuneular segments of Orthoeerida

of the Boda Limestone. Note the different septal thieknesses. A. Striatocycloceras isbergi sp. nov.,

PMU 26681, Kallholn. B. Dawsonoceras fenestratum (Eiehwald, 1860), PMU 26706, Kallholn.

C. Pleurorthoceras osmundsbergense sp. nov., NRM-PZ Mo 150102e, Osmundsberget. D. Isorthoceras

angelini sp. nov., PMU 26784, Kallholn.

KROGER B., Cephalopods of the Boda Limestone

Striatocycloceras? sp.

Fig. 15

Material

One speeimen: PMU 26699, Kallholn, Siljan Distriet, Sweden; Boda Limestone.

Description

The 90 mm long shell fragment eonsists in part of a body ehamber. The maximum width of the fragment

is 57 mm, from whieh a eoneh of ea. 70 mm in diameter may be reeonstmeted, based on the eross

seetion. The eoneh was slightly eurved and annulated with prominent, direetly transverse annuli. The

distanee between the annuli is 10-15 mm, with a tendeney to deerease toward the aperture (ea. 0.14-0.2

of eoneh eross seetion; seven to five ehambers in a distanee equal to the eorresponding eross seetion).

The shell surfaee is ornamented by narrowly, irregularly spaeed distinetive growth lines (ea. 4 per one

millimeter; Fig. 15). Additionally, on the inner surfaee of the shell, fine ineonspieuous longitudinal lirae

are visible (ea. one per millimeter).

Fig. 15. Fragments of the outer shell and negative shell impression of Striatocyclocerasl sp.,

PMU 26699, Kallholn, Boda Limestone. Seale bar =10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Remarks

This orthoconic shell fragment is only provisionally assigned within Striatocycloceras. Nothing is

known about the internal eharaeters of this speeimen. This generie identifieation is solely based on

the annulated orthoeonie shell, whieh is additionally transversally striated, a feature that is known

exelusively from Striatocycloceras in the Late Ordovieian beds of Baltoseandia.

Family Dawsonoeeratidae Flower, 1962

Genus Dawsonoceras Hyatt, 1884

Type species

Orthoceras annulatum Sowerby, 1816, Wenloek Series, Coalbrookdale, Shropshire, England; by original

designation.

Diagnosis

Slender, eireular or slightly eompressed orthoeones with symmetrieally eurved septa and straight

transverse sutures; sutures parallel to the annulations in eaeh groove of the annulations; annulations

regularly spaeed, with fine transverse ornamentation or growth lines; growth lines in some speeies

festooned. In some speeies with longitudinal ridges that may form nodes at the ridges of the annulations;

siphunele subeentral in early growth stages, eentral in late growth stages, narrow, but expanded within

the ehambers; septal neeks short suborthoehoanitie to aehoanitie. Ineipient annulosiphuneular deposits.

Remarks

The diagnosis is adopted from Kroger & Isakar (2006). There the genus was revised and diseussed in

detail.

Dawsonoceras fenestratum (Eiehwald, 1860)

Figs 13A, 14B, 16A-B

Cycloceras fenestratum Eiehwald, 1860: 1231, 1232, pi. 48: 14a-b.

Dawsonoceras fenestratum - Kroger & Isakar 2006: 156, figs 8b, 10b, 12e, f-g (with synonymy). —

Kroger 2007: 597.

Diagnosis

Dawsonoceras with angle of expansion of less than ten degrees in juvenile stages. Tubular adult body

ehamber has diameter of approximately 25 mm; five to six annulations oeeur at distanee similar to shell

diameter; approximately 20 longitudinal lirae oeeur around shell eireumferenee, approximately fifteen

growth lines or transverse striae oeeur per eyele of annulations; septal neeks aehoanitie; siphunele

subeentral, expanded within ehambers. Mural and hyposeptal eameral deposits are known. (Adopted

from Kroger & Isakar 2006.)

Type locality and horizon

Monuste (Kima), western Estonia, Eate Ordovieian.

Material examined

Two speeimens, PMU 26700 and 26701, Osmundsberget, Siljan Distriet; fifteen speeimens (PMU

26702-26716), Kallholn, Siljan Distriet; all from the Boda Eimestone, Boda Core Member, late Katian.

KROGER B., Cephalopods of the Boda Limestone

Description

The external eharaeters were deseribed in detail by Kroger and Isakar (2006; see also Figs 16A-B).

In speeimen PMU 26706 additional details of the siphunele are preserved. Speeimen PMU 26706 is a

fragment of a phragmoeone with a diameter of 18-21 mm and a length of 28 mm . The ehamber distanee

is relatively eonstant at ea. 4 mm. The siphunele is slightly eeeentrie at the adoral end and ea. 8 mm

distant from the eoneh margin (SPR 0.38). The siphuneular diameter is 1.3 mm at the adapieal end

(0.07 of the eorresponding eoneh eross seetion); there the septal perforation is only 0.8 mm wide. The

siphuneular segments are barrel-shaped; rapidly inereasing in diameter elose to the septal perforation,

the side direeted toward the eoneh eenter bends inward slightly, forming a shallow eoneave eonneeting

ring segment (Figs 13A, 14B). The asymmetrieal shape of the eonneeting ring was noted in material

previously deseribed by Kroger & Isakar (2006). The septal neeks are short and suborthoehoanitie.

Shallow hyposeptal deposits oeeur at the adapieal five ehambers.

Remarks

This speeies was revised by Kroger & Isakar (2006) and its main features were deseribed based on

speeimens from the Porkuni Formation of Estonia. Here, additional data regarding the variation of

the external eharaeters and features of the siphunele are noted. The oeeurrenee of hyposeptal eameral

Fig. 16. Dawsonoeeratidae and Proteoeeratidae of the Boda Limestone. A-B. Dawsonoceras fenestratum

(Eiehwald, 1860), Kallholn. A. PMU 26702, nearly mature speeimen with adorally deereasing angle of

expansion. B. PMU 26712, juvenile speeimen. C. Gorbyoceras sp. A, PMU 26772, Osmundsberget.

D. Gotybocems sp. B, PMU26773, Kallholn. E. Dawsonocerasstumburi sp. nov., PMU26717, holotype,

Kallholn. F. Gorbyoceras alternestriatum (Strand, 1934) eomb. nov., PMU 26771, Unskarsheden. Seale

bars: A-C, E = 10 mm; D = 10 mm; F = 10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

deposits in specimens of Dawsonoceras fenestratum (Eichwald, 1860) from the Boda Limestone (see

below) is included within the diagnosis herein.

The conch measurements reveal a clear tendency of a decrease in angle of expansion with increasing

conch diameter (Kroger & Isakar 2006). The mature body chamber of D. fenestratum is nearly tubular,

whereas in juvenile conchs the maximum expansion reaches 10° (PMU 26708 with cross section

diameters of 9-14 mm; compare Fig. 16A-B). This is in agreement with the measurements listed by

Kroger & Isakar (2006). Additionally, the relative distance of the transverse annuli is highly variable,

but lacks a clear ontogenetic trend and varies between 0.16 and 0.3 of the corresponding conch diameter

(mean 0.25, n=12). The number of longitudinal lirae is fixed in each specimen, but varies among different

specimens from 20 to 31.

These external features are well within the range of variability of the Trenton dawsonoceratid Orthoceras

beauportense Whiteaves, 1898, from which the internal characters are unknown. It is probable that this

species should be synonymized with D. fenestratum. Chen & Zou (1984) reported a similar species from

the late Katian Sheshan Formation of North China, which they assign to Anaspyroceras beauportense

(Whiteaves, 1898) but provided no details regarding internal characters. This specimen probably should

also be assigned to D. fenestratum.

Stratigraphic and geographic range

NabalaWormsi Regional Stages, Estonia (questionable, see Kroger & Isakar 2006); Porkuni Formation,

Estonia; Boda Limestone, Siljan District, Sweden; late Katian-Himantian, Ordovician.

Dawsonoceras stumburi sp. nov.

um:lsid:zoobank.org:act:lClB98BD-F65E-4D72-8A31-203A0730E970

Figs 16E, 17B

Dawsonoceras sp. - Kroger & Isakar 2006: 157, figs lOe, j, 12h.

Diagnosis

Dawsonoceras with angle of expansion of ca. 5° and circular cross section; ca. five relatively shallow

annulations occur at a distance similar to shell diameter; approximately 40 longitudinal lirae occur

around shell circumference, more than 10 pronounced transverse striae occur per cycle of annulations;

septal necks achoanitic; siphuncle subcentral, fusiform, expanded within chambers.

Etymology

In honor of Heino Stumbur (Tallinn), an Estonian geologist and paleontologist who first described this

form in his unpublished diploma thesis (Stumbur 1955) under the nomen nudum of Spyroceraspaulum.

Holotype

PMU 26717.

Type locality and horizon

Kallholn, Siljan District, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovician.

Description

The holotype is a piece of phragmocone with a length of 72 mm and a diameter of 14-20 mm (angle of

expansion 5°), with a circular conch cross section. The sutures are directly transverse, with a distance

of 3 mm at a diameter of 15 mm (0.2 of corresponding conch cross section; Fig. 16E). The conch is

KROGER B., Cephalopods of the Boda Limestone

Fig. 17. Shell ornamentation of seleeted Orthoeerida of the Boda Formation. A. Isorthoceras ef

elongatocinctum (Portloek, 1843), PMU 26825, Kallholn, adoral part of the speeimen. B. Dawsonoceras

stumburi sp. nov., PMU 26717, holotype, Kallholn. C. Gorbyoceras sp. A, PMU 26772, Osmundsberget.

D. Isorthoceras ef elongatocinctum (Portloek, 1843), same speeimen as in A, adapieal part of speeimen.

E. Isorthoceras junceum (Hall, 1847), PMU 26834, Kallholn. F. Gorbyoceras alternestriatum (Strand,

1934) eomb. nov., PMU 26771, Unskarsheden. G. Isorthoceras curvilineatum sp. nov., PMU 261 HI,

holotype, Osmundsberget. H. Isorthoceras angelini sp. nov., PMU 26774, holotype, Kallholn. I.

Isorthoceras suave (Angelin in Angelin & Lindstrom, 1880) eomb. nov., PMU 26835, Kallholn. Seale

bar = 5 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

ornamented with 40 distinetly raised longitudinal lirae around eireumferenee. Additionally, the eoneh

is annulated. The distanee between two sueeessive annulations is 3.5 mm at a eorresponding eoneh

diameter of 16 mm (0.22 of distanee similar to eorresponding eoneh diameter). Approximately 20

distinet and direetly transverse striae oeeur in a single eyele of annulation (Fig. 17B).

Comparison

This speeies differs from D. fenestratum in having a higher number of longitudinal lirae (ea. 20-30 in

D. fenestratum against ea. 40 in D. stumburi sp. nov.). Additionally, the transverse annulation appears

to be less pronouneed and slightly more widely spaeed in D. stumburi sp. nov., but the transverse striae

are narrower than in D. fenestratum.

The external eharaeters off), stumburi sp. nov. are identieal to those of Orthoceras clathratum Hall, 1847

from the Katian Middleville Formation of New York (see, e.g., Foerste 1928). But a synonymization is

at present not possible, as the internal eharaeters of this speeies are not known.

Stratigraphic and geographic range

Vormsi Regional Stages, Estonia (Kroger & Isakar 2006); Boda Limestone, Siljan Distriet, Sweden; late

Katian, Ordovieian.

Genus Palaeodawsonocerina Kroger & Isakar, 2006

Type species

Spyroceras senckenbergi Teiehert, 1930, from Lyekholm, Estonia; “Lyekholm stage” of Teiehert (1930),

Vormsi/Pirgu Regional Stage, late Katian, Late Ordovieian.

Diagnosis

Straight or slightly eyrtoeonie, eireular or subeireular shell, with prominent, narrowly spaeed annulations,

growth lines and numerous subordinate filiform longitudinally raised lines, produeing a finely retieulate

pattern. Siphunele eentral or slightly eeeentrie, slightly expanded, with aehoanitie to very short

orthoehoanitie septal neeks. Apex blunt, slightly eyrtoeonie, annulated. (From Kroger & Isakar 2006.)

Palaeodawsonocerina senckenbergi (Teiehert, 1930)

Figs 12A, 18C

Spyroceras senckenbergi Teiehert, 1930: 280, pi. 5, figs 3, 4.

Palaeodawsonocerina senckenbergi - Kroger & Isakar 2006: 154, figs 8a, lOi, 12d-e, 12h (with

synonymy).

non Spyroceras senckenbergi -T)z\k 1984: 122, 125, pi. 35, fig. 5, text-figs 48a, 49.20.

Diagnosis

Straight, slightly eompressed eoneh with very low apieal angle of approximately l°-2°; adult

dorsoventral diameter approximately 25 mm; with five to six annulations at a distanee that equates to

the eorresponding shell diameter in adult speeimens; annulations straight or very slightly oblique toward

the growth direetion and regularly spaeed; very fine growth lines, about 50 in a eyele of annulation; very

fine longitudinal striae or raised lines, about five to seven per millimetre; suture line follows the ridges

of the annulations; siphunele eentral, slightly expanded within the ehambers; septal perforation about

0.07 of the shell diameter. (From Kroger & Isakar 2006.)

KROGER B., Cephalopods of the Boda Limestone

Fig. 18. Shell ornamentation of seleeted Cephalopoda of the Boda Formation. A. Order, gen. et sp.

indet., PMU 26950, Kallholn, lateral view. B. Palaeodawsonocerinal nicolletoides sp. nov., PMU

26727, holotype, Kallholn. C. Palaeodawsonocerina senckenbergi (Teiehert, 1930), PMU 26718,

Kallholn. D. Geisonoceras wegelini (Angelin in Angelin & Lindstrom, 1880) eomb. nov., PMU

26745, Unskarsheden. E. Pleurorthoceras osmundsbergense sp. nov., NRM-PZ Mo 150126, holotype,

Osmundsberget. F. Warburgoceras longitudinale (Angelin />2 Angelin & Lindstrom, 1880) eomb. nov.,

NRM-PZ Mo 154065, Unskarsheden. G. Redpathoceras depressum sp. nov., PMU 26931, Kallholn.

Seale bar = 5 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

Type locality and horizon

Lyckholm, Estonia, “Lyckholm stage” of Teichert (1930), Vormsi/Pirgu Regional Stage, late Katian,

Late Ordovieian.

Material examined

Seven speeimens (PMU 26718-26724), Kallholn; two speeimens (PMU 26725-26726), Osmundsberget,

Siljan Distriet, Sweden; all Boda Limestone, Boda Core Member, late Katian, Late Ordovieian.

Remarks

This speeies was deseribed in detail by Kroger & Isakar (2006). The material from the Boda Limestone

reveals information regarding the ornamentation. PMU 26718 reveals that the annuli are sharply erested

and symmetrieal in longitudinal eross seetion (Figs 12A, 18C). The longitudinal ornamentation eonsists

of fine raised lirae, ea. 0.5 mm apart where the eoneh diameter is 16 mm. Additional, faint, direetly

transverse growth lines oeeur that are more pronouneed in mature growth stages. The largest speeimen

from the Boda Limestone is 25 mm in diameter (PMU 26724) and supports an earlier assessment (Kroger

& Isakar 2006) that the diameter at maturity of individuals of this speeies is ea. 25 mm.

Stratigraphic and geographic range

KeilaAT)rmsi Regional Stages, Estonia (Kroger & Isakar 2006); Boda Limestone, Siljan Distriet,

Sweden; Katian, Ordovieian.

Palaeodawsonocerina? nicolletoides sp. nov.

um:lsid:zoobank.org:aet:4ElD7CA7-028A-4174-94DF-D86B525B5F94

Figs 12D-E, 18B

Diagnosis

Slender, large eyrtoeones with a slightly eompressed eoneh eross seetion and a pronouneed annulation;

prosiphuneular eoneh margin wider and more Fattened than antisiphuneular margin in eross seetion;

adult eoneh diameter ea. 30 mm; annuli relatively wide, ea. 4 per distanee equal to eoneh diameter,

ridges of annuli sharp and narrow, grooves wider and more rounded; eoneh surfaee ornamented with

fine longitudinal striae and faint, very shallow, rounded longitudinal ridges; siphunele eeeentrie, lying

on eoneave side of eoneh eurvature, septal perforation ea. 0.14 of eoneh eross seetion.

Etymology

The name refers to Orthoceras nicolleti Clarke, 1897, whieh is very similar to Palaeodawsonocerinal

nicolletoides sp. nov. However, this speeies differs from O. nicoletti in having a less eentrally positioned

siphunele and a more eireular eoneh eross seetion.

Type material

Holotype

PMU 26727.

Paratype

One paratype: PMU 26728 from Kallholn, Siljan Distriet, Sweden; Boda Limestone, Boda Core Member,

late Katian, Late Ordovieian.

Type locality and horizon

Kallholn, Siljan Distriet, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

KROGER B., Cephalopods of the Boda Limestone

Description

Speeimen PMU 26728 is a 105 mm long fragment of a nearly eomplete eurved body ehamber, with

a diameter that inereases from 28 to 32 mm (angle of expansion 2°; Fig. 12D-E). The eoneh eross

seetion is nearly eireular at the base of the body ehamber and slightly eompressed at the aperture. The

shell is strongly annulate, with a distanee between annuli that inereases adorally from 7 mm (0.24 of

eorresponding eoneh diameter) to 10 mm (0.31 of eorresponding eoneh eross seetion). The seeond most

adoral of the ridges is signifieantly lower in amplitude. Generally the ridges of the annuli are sharper

than the valleys, whieh are broadly rounded. The annuli are slightly oblique, inelined adorally on the

eoneave side of the eoneh eurvature.

The holotype (PMU 26727), is a small pieee of phragmoeone 28 mm in diameter. The only preserved

septum of this speeimen is shallow eonvex (height of eurvature 6 mm, 0.21 of eoneh diameter). The

eoneh eross seetion is not perfeetly eireular, but rounded triangular with a pointed antisiphuneular and

a broad prosiphuneular side. The septal perforation is 4 mm wide and eeeentrieally positioned, with a

distanee of 10 mm from the eoneh margin (SPR 0.36) on the eoneave side of the eoneh eurvature. The

shell is thin, 0.5 mm in the grooves of the annulation and thiekens toward the ridges. The shell surfaee

is ornamented with very fine longitudinal striae (ea. 10 per one millimeter), and very shallow, rounded,

ineonspieuous longitudinal ridges (Fig. 18B).

Remarks

The generie assignment of this speeies is uneertain beeause only fragments of the mature body

ehamber are known and internal details are a matter of speeulation. However, beeause the eonspieuous

ornamentation is eharaeteristie of other speeies of Palaeodawsonocerina, the speeies is provisionally

assigned to that genus.

Comparison

The speeimens deseribed above are nearly identieal to Orthoceras nicolleti from the Platteville

Formation, Sandbian-early Katian of Wiseonsin (Foerste 1932) with respeet to the wide, pronouneed

annulation and the eurvature of the eoneh. The Platteville speeimen is poorly known, as no details of the

eoneh surfaee are preserved and this is the only known speeimen. It differs from Palaeodawsonocerina?

nicolletoides sp. nov. in its larger size, eentral siphunele and nearly eireular eoneh eross seetion.

Teiehert (1930) assigned a speeimen from the Pirgu Regional Stage of Estonia to Syproceras textu-

maraneum (Roemer, 1861) whieh eanbe eompared with Orthoceras nicolleti Palaeodawsonocerina?

nicolletoides sp. nov. with regard to its relatively large adult size, eurved body ehamber and distant

annulations. The ornamentation of this speeimen is not preserved, easting a degree of uneertainty on

Teiehert’s (1930) assignment to Spyroceras textumaraneum. The speeimen of Teiehert (1930) differs

from Palaeodawsonocerina? nicolletoides sp. nov. in having a narrower and shallower annulation and

a larger adult size.

Balashov (1975: pi. 1, figs 3-6) figured several annulated and longitudinally striated orthoeerids under

the name Gorbyoceras duncanae Flower, 1946. However, eoneh shape, ornamentation and internal

eharaeters indieate that these speeimens are better assigned to Palaeodawsonocerina. The ornamentation,

annulation and general shell shape of the speeimen figured in Balashov (1975: pi. 1, figs 7) is similar to

Palaeodawsonocerina? nicolletoides sp. nov., but a direet eomparison based on the ineomplete material

is not possible.

Stratigraphic and geographic range

Boda Limestone, Siljan Distriet, Sweden; late Katian, Ordovieian.

European Journal of Taxonomy 41: 1-110 (2013)

Family Eriditidae Chen in Chen et al., 1981

Genus Nathorstoceras gen. nov.

um:lsid:zoobank.org:aet:3415D639-EFD4-404C-90EA-DA8AAAA930E5

Type species

Nathorstoceras kallholnense gen. et sp. nov., Kallholn, Dalama, Sweden, Boda Eimestone, Boda Core

Member, late Katian, Ordovieian by montotypy.

Diagnosis

Straight or slightly eurved longieones with annulated or smooth shell, ornamented with transverse lirae

or eonspieuous growth lines, whieh form shallow sinus on prosiphuneular side; septal spaeing relatively

narrow with ea. five ehambers per distanee equal to eorresponding eoneh diameter; siphunele subeentral

or slightly eeeentrie on eonvex side of eoneh eurvature; septal foramen narrow; siphuneular segments

abruptly expanded at septal foramen, septal neeks aehoanitie; epi- and hyposeptal deposits present;

endosiphuneular deposits not known at present.

Etymology

In honour of Alfred Gabriel Nathorst (1850-1921), Swedish palaeobotanist, geologist, and polar

researeher, for his pioneering work on the Palaezoie of the Siljan strueture (Nathorst 1885).

Comparison

This genus is unique among Ordovieian orthoeerids. The rapidly expanding siphuneular segments

are similar as eompared with late Palaeozoie pseudorthoeerids, sueh as Adnatoceras Flower, 1939.

However, eharaeteristie pseudorthoeerid endosiphuneular deposits are not known from speeimens

of Nathorstoceras gen. nov. With its annulate eoneh N. kallholnense sp. nov. resembles Mid Silurian

paraphragmitids, whieh differ in having less expanded siphuneles and suborthoehoanitie septal neeks.

In the Estonian Porkuni Formation smooth orthoeones oeeur, with aehoanitie septal neeks and broadly

expanded siphuneular segments (Eriditidae gen. et. sp. indet. in Kroger 2007). These speeimens are

poorly preserved or very fragmentary, and it is diffieult to eompare them with the relatively large

fragments of the speeimens from the Boda Eimestone, but their similarity in the septal neek/siphuneular

segment shape suggest that they may represent speeies of Nathorstoceras gen. nov.

Monomuchites bacotensQ Balashov, 1975 from the Molodov Horizon of Podolia is known from a single

fragmentary speeimen only. However, the polished eross seetion figured in Balashov (1975: pi. 1, fig. 7)

shows a marked similarity with the Boda speeimens of Nathorstoceras gen. nov. M. bacotense, differs

from the Boda speeimen mainly in having a eireular eoneh eross seetion. Herein, it is interpreted as

another speeies of Nathorstoceras gen. nov.

Species included

Nathorstoceras kallholnense sp. nov., Nathorstoceras adnatum sp. nov., Nathorstoceras bacotense

(Balashov, 1975) eomb. nov.

Stratigraphic and geographic range

Boda Eimestone, Dalama, Sweden, late Katian, Eate Ordovieian.

KROGER B., Cephalopods of the Boda Limestone

Fig. 19. Orthoeerida of the Boda Limestone. A. Nathorstoceras adnatum sp. nov., PMU dl440, holotype,

Kallholn, lateral view. B-C. Nathorstoceras kallholnense sp. nov., PMU 26730, Kallholn, eomplete

body ehamber. B. Lateral view. C. view from prosiphuneular side. D. Geisonoceras wegelini (Angelin in

Angelin & Lindstrom, 1880) eomb. nov., PMU 261 Al, Unskarsheden, lateral view. E. Ordogeisonoceras

foerstei (Strand, 1934) eomb. nov., PMU 26762, Kallholn, lateral view. F. Nathorstoceras kallholnense

sp. nov., PMU 26729, holotype, lateral view, note siphunele on left side. Seale bar = 10 mm for all

figures.

European Journal of Taxonomy 41: 1-110 (2013)

Nathorstoceras kallholnense sp. nov.

um:lsid:zoobank.org:act:5393FB9D-6642-4D8D-9F4B-C2C741B7CC57

Figs lOD, 13E, 19B-C, F, 20B, 21A

Diagnosis

Nathorstoceras gen. nov. with slightly curved annulated conch; angle of expansion of 10-13 °; annulations

more pronounced in late growth stages; shell sculpture of irregularly spaced, pronounced transverse

growth lines, less than one millimeter apart; distance between annulations ca. 0.3 of corresponding

conch height; annuli and growth lines with shallow sinus on prosiphuncular side; conch cross section

compressed; width/height ratio ca. 0.87; septal distance ca. 0.3 of corresponding conch height; siphuncle

eccentric (SPR ca. 0.3); septal perforation ca. 0.07 of corresponding conch height; siphuncular segments

abruptly expanded at septal foramen with maximum diameter ca. 0.14 of conch diameter; epi- and

hyposeptal deposits present; endosiphuncular deposits not known.

Etymology

Refers to the type locality.

Type material

Holotype

PMU 26729.

Paratypes

Fourparatypes: PMU dl376,26730-26732, Ifom Kallholn, Siljan District, Sweden; all Boda Limestone,

Boda Core Member, late Katian.

Type locality and horizon

Kallholn, Silj an District, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovician.

Description

The holotype is a piece of phragmocone ca. 60 mm long, a height of27-33 mm and a width at the adoral

end of 33 mm (width/height ratio 0.87, angle of expansion 10.4°) (Figs 10 D, 19F). The conch is weakly

annulated with a distance between two successive annuli ca. 0.3 that of the corresponding conch cross

section, and ornamented with pronounced, irregularly spaced growth lines or raised bands, each with a

width of less than a millimeter. The conch is slightly crushed, and nearly straight, with an eccentrically

positioned siphuncle. Because of the fragmented shell the siphuncle appears to be positioned on the

convex side of the shell curvature. A reconstruction of the shell indicates that the siphuncle is on the

convex side of a very slightly curved phragmocone. At the apical end of the specimen the distance

of the siphuncle from the conch margin is 9 mm (SPR 0.33). The siphuncle is much wider than the

septal perforation, and at the adapical end of the specimen the septal perforation is ca. 1.8 mm, and the

maximum diameter of the siphuncle is 3.5 mm (0.07 and 0.13 of the corresponding conch cross section,

respectively) (Figs 20B, 21 A). The septa are 9 mm apart where the corresponding conch height is 30

mm. The septal necks are achoanitic and siphuncular segments (connecting rings) are abruptly expanded

at the septal foramen. At the adapical end of the specimen epi- and hyposeptal deposits occur.

Specimen PMU 26730 is a fragment of a body chamber with a length of 72 mm, a height of 29^4

mm, and a width of 26-38 mm (width/height ratio 0.86-0.89, angle of expansion 11.8°) (Fig. 19B-C).

The conch cross section is elliptical, with the antisiphuncular side slightly more sharply rounded. The

conch is annulated with rounded, shallow annuli 12 mm apart at a corresponding conch height of 40

mm. In addition, pronounced, irregularly spaced growth lines run parallel to the annuli, both of which

are slightly oblique and form a shallow sinus on the prosiphuncular side of the conch. The siphuncle is

KROGER B., Cephalopods of the Boda Limestone

Fig. 20. Polished median seetions of Nathorstoceras sp. nov., Kallholn, Boda Limestone.

A. Nathorstoceras adnatum sp. nov., PMU 26733, holotype, Kallholn. B. Nathorstoceras kallholnense

sp. nov., PMU 26729, holotype, Kallholn. Seale bar = 10 mm for both figures.

European Journal of Taxonomy 41: 1-110 (2013)

eccentric (SPR 0.28), lying on the convex side of the conch curvature. Specimen PMU 26731, which

is a part of a phragmocone and body chamber, is the largest specimen of this species with a maximum

conch height of ca. 60 mm.

Comparison

Nathorstoceras kallholnense sp. nov. differs from N. adnatum sp. nov. in having a more pronounced

annulated conch and a less compressed conch cross section.

Stratigraphic and geographic range

Boda Limestone, Dalama, Sweden, late Katian, Late Ordovician.

Nathorstoceras adnatum sp. nov.

um:lsid:zoobank.org:act:58064C88-D4A3-4CA4-B6EA-DE719EE0F724

Figs IOC, 13F, 19A, 20A,21B

Diagnosis

Nathorstoceras with nearly straight and very weakly annulated conch with angle of expansion of 8°;

annulations more pronounced in late growth stages; shell ornamented with regularly spaced transverse

lirae and distance between annulations ca. 0.2 of corresponding conch height; annuli and lirae form

shallow sinus on prosiphuncular side; conch cross section compressed with width/height ratio of ca.

0.8; septal distance ca. 0.24 of corresponding conch height; siphuncle subcentral with SPR 0.41; septal

perforation with diameter of ca. 0.05 of corresponding conch height; siphuncular segments abruptly

expanded at septal foramen with maximum diameter of ca. 0.14 of corresponding conch cross section;

endosiphuncular deposits unknown.

Etymology

Refers to the strongly expanded, adnate siphuncular segments of this species.

Holotype

PMU 26733.

Type locality and horizon

Kallholn, Siljan District, Sweden, Boda Eimestone, Boda Core Member, late Katian, Ordovician.

Description

The specimen is a portion of phragmocone ca. 50 mm long, with a height of 37^4 mm and a width at

the adoral end of 30 mm (width/height ratio 0.81, angle of expansion 8°) (Fig. IOC, 19A). The conch is

faintly annulated with a distance between two successive annuli of ca. 0.2 of the corresponding conch

cross section, and ornamented with pronounced, regularly spaced lirae, with a distance between two

subsequent lirae of ca. 1.5 mm. The conch is is nearly straight, with a subcentrally positioned siphuncle;

at the apical end of the specimen its distance from the conch margin is 15 mm (SPR 0.41). The connecting

ring is much wider than the septal perforation (Figs 20A, 2 IB). At the adapical end of the specimen the

septal perforation is ca. 2 mm and the maximum diameter of the siphuncle is 5 mm (0.05 and 0.14 of the

corresponding conch cross section, respectively). The sutures are directly transverse and form shallow

lateral lobes. At the adapical end of the specimen the distance between two septa is 9 mm (0.24 of

corresponding conch cross section). The septal necks are achoanitic and the siphuncular segments are

adnate, abruptly expanded at septal foramen. No cameral and endosiphuncular deposits occur.

KROGER B., Cephalopods of the Boda Limestone

Comparison

See eomparison with Nathorstoceras kallholnense sp. nov. (above).

Family Geisonoeeratidae Zhuravleva, 1959

Genus Geisonoceras 1884

Type species

Orthoceras rivale Barrande, 1866, Prague Basin, Czeeh Republie, Ludlovian, Silurian; by original

designation.

Diagnosis

Slender longieonie orthoeones or slightly eyrtoeonie longieones with eireular to subeireular eross

seetion; ornamented with broad transverse bands between whieh are fine growth lines; transverse

bands are slightly oblique forming shallow hyponomie sinus; sutures direetly transverse or slightly

Fig. 21. Reeonstruetion of the details of the septal neeks and eonneeting ring of Nathorstoceras sp.

nov., Kallholn, Boda Limestone. A. Nathorstoceras kallholnense sp. nov., PMU 26729, holotype.

B. Nathorstoceras adnatum sp. nov., PMU 26733, holotype.

European Journal of Taxonomy 41: 1-110 (2013)

oblique; siphuncle subcentral; septal necks short orthochoanitic; connecting rings slightly expanding

within chambers; weak annulosiphonate deposits concentrated at septal foramen in adapical siphuncular

segments; camerae with episeptal and hyposeptal deposits. (Adopted from Sweet 1964c).

Geisonoceras wegelini (Angelin /^Angelin & Lindstrom, 1880) comb. nov.

Figs 2, 131, 18D, 19D, 22

Orthoceras wegelini Angelin />? Angelin & Lindstrom, 1880: 5, pi. 6, fig. 6.

Orthoceras saksbyense Teichert, 1930: 277, pi. 5, fig. 2.

Diagnosis

Slender orthocones with angle of expansion of ca. 5° or less, circular or slightly compressed conch

cross section; chamber height of ca. 0.3-0.5 of distance similar to corresponding cross section diameter;

ornamented with obliquely transverse, irregularly spaced growth bands; distance between growth

bands 0.3-3 mm; siphuncular position eccentric (SPR ca. 0.2); siphuncular segments tubular, short

orthochoanitic to suborthochoanitic septal necks; weakly developed annulosiphuncular deposits are

restricted to the position of the septal necks; hypo- and episeptal deposits occur.

Type material

Lectotype

NRM Mo 152346 (designated herein).

Fig. 22. Geisonoceras wegelini (Angelin Angelin & Lindstrom, 1880) comb, nov., PMU 26740, from

Unskarsheden, Boda Limestone. Same specimen as in Fig. 131.

KROGER B., Cephalopods of the Boda Limestone

Paralectotypes

Two paraleetotypes (NRM Mo 152347, 152348) from Ostbjorka, Boda Limestone, latest Katian.

Type locality and horizon

Ostbjorka, Siljan distriet, Dalama, Sweden; Boda Limestone, Boda Core Member, late Katian,

Ordovieian.

Other material examined

Five speeimens (PMU 26734-26738) from Kallholn; 19 speeimens (PMU 26739-26757) from

Unskarsheden, Siljan Distriet; all Boda Limestone, latest Katian.

Description

The leetotype is a relatively poorly preserved fragment of a phragmoeone with an angle of expansion

whieh eannot be measured exaetly beeause of this fragmentary status. It agrees with respeet to eoneh

ornamentation, general eoneh shape and position of the siphunele with the speeimen PMU 26747.

Speeimen PMU 26747 is a well preserved portion of phragmoeone 83 mm long, with a slightly

eompressed seetion (ratio width/height 0.93), and a eoneh height of 43^9 mm (angle of expansion 4.1°)

(Figs 2, 19D). The eoneh surfaee is ornamented with irregularly spaeed bands with fine deep grooves in

between. Bands and grooves are parallel to eaeh other. The distanee between the grooves varies between

0.2 and 0.3 mm in this speeimen (Fig. 18D). The bands are oblique, forming a shallow sinus on the

prosiphuneular side. At the apieal end of the speeimen, the siphunele is positioned at ea. 9 mm from the

eoneh margin (SPR 0.21). There the siphuneular perforation is 4 mm wide (ea. 0.09 of eorresponding

eoneh height). The most adapieal septum is moderately eonvex with a height of eurvature of ea. 10 mm

(0.23 of eorresponding eoneh height).

The mean of the angle of expansion of eight measured speeimen is ea. 4.2° (minimum 2.19°, maximum

5.19°). The eeeentrieity of the siphunele is relatively eonstant; in three measured speeimens it varies

between a SPR of 0.17 to 0.22.

The largest speeimen, PMU 26752, with a eross seetion diameter of 92 mm, possesses a pronouneed

eonstrietion on the east of the body ehamber at ea. 35 mm adapieally of the adoral end of the fragment.

The shape of the siphunele and septal neek is preserved in speeimens PMU 26745 (Fig. 18D), 26740

(Figs 131, 22), 26741 and 26746. These fragments have eoneh diameters between 24 and 58 mm. In

all five speeimens the siphunele is nearly tubular, very slightly eonstrieted at the position of the septal

perforation and the septal neeks are short orthoehoanitie to suborthoehoanitie, with a length of ea. 0.14

of the length of the siphuneular segment (= ehamber height). At the position of the septal neek, shallow

annulosiphuneular deposits are developed at parts of the septal neeks whieh are direeted toward the

eoneh eenter. Hyposetal, episeptal and mural deposits oeeur (see, e.g.. Fig. 2).

Remarks

The transverse ornamentation is subdued and visible only in well preserved speeimens. In slightly

weathered speeimens, the eoneh surfaee appears perfeetly smooth and in steinkems with high

probability it is not preserved. Therefore, poorly preserved speeimens eould be mistakenly assigned

to the smooth Pleurorthoceras. Teiehert (1930) deseribed a smooth longieone under the name of

Orthoceras saksbyense with exaetly the same eoneh dimensions, shape and distanee of septa, position

and d im ension of siphunele and septal neeks whieh have no signs of ornamentation. Therefore, with

a very high probability this speeies is eonspeeifie with Geisonoceras wegelini Angelin in Angelin &

Lindstrom, 1880 eomb. nov. and is synonymised with the latter, herein.

European Journal of Taxonomy 41: 1-110 (2013)

Comparison

Geisonoceras is a genus which has been widely used as a wastebasket taxon for a variety of straight

longicones with a transverse ornamentation. Currently it comprises more than fifty species. Probably,

most of them are not closely related to the genotype. G. wegelini comb. nov. is very similar to the genotype

with respect to its ornamentation and internal characters; it differs in having a strictly orthoconic shell

and only poorly developed annulosiphuncular deposits. The latter may be an artifact, as only relatively

large fragments with internal structures preserved are known from G. wegelini comb. nov.

Stratigraphic and geographic range

Vormsi Regional Stages, Estonia (Teichert 1930); Boda Limestone, Siljan District, Sweden; late Katian,

Ordovician.

Geisonoceras? sp.

Fig. 23H

Material

PMU 26758, from Kallholn, Siljan District, Sweden, Boda Limestone, Boda Core Member, late Katian,

Ordovician.

Description

The specimen represents the juvenile part of a phragmocone 45 mm long, having a diameter of 5-8.3

mm (angle of expansion 4.4°), and a circular conch cross section. The shell is ornamented with obliquely

transverse adorally imbricated striae (Fig. 23H). Adorally the conch widens at each stria, which results

in an annulated pattern with a sharp ridge at the adoral end of each of them. The distance between two

successive striae varies widely from 0.3 to 1.5 mm. At the adoral end a trace of a healed predation

additionally causes irregularities in the distance of the transverse elements.

Remarks

This small specimen might represent the juvenile stage of Geisonoceras wegelini (Angelin in Angelin

& Lindstrom, 1880) comb. nov. Only relatively large fragments of G. wegelini are known. These

fragments are ornamented with obliquely transverse bands with highly irregular spacing. The pattern of

ornamentation of G. wegelini comb. nov. resembles that of specimen PMU 26758, but is shallower and

not imbricated. Both forms are interpreted as separate species, because intermediate growth stages are

not available for further study.

Comparison

The specimen PMU 26758 differs from known juvenile specimen of Tyrioceras subannulare (Portlock,

1843) (see Evans 1993) and from Imbricatoceras ascendens (Blake, 1882) (see Holland 1993) in having

a strongly irregularly spaced transverse ornamentation. Known species of Thyriocerias differ in having

a curved and more regularly spaced transverse ornamentation.

Genus Ordogeisonoceras Frey, 1995

Type species

Orthoceras amplicameratum Hall, 1847 from the Trenton Formation, latest Katian, Middleville, New

York, USA.

KROGER B., Cephalopods of the Boda Limestone

Diagnosis

Slender, gradually expanding orthoeones; ornamented with fine longitudinal lirae; eireular in eross

seetion with straight, transverse sutures; ehamber distanee ea. one-half of the eorresponding eoneh

Fig. 23. Orthoeerida of the Boda Limestone. A. Pleurorthoceras osmundsbergense sp. nov., NRM-PZ Mo

150126, holotype, Osmundsberget. B. Isorthoceras suave (Angelin />2 Angelin & Lindstrom, 1880) eomb.

nov.,PMU26835,Kallholn.C./yor//zocera^yf/«ceww (Hall, 1847),PMU26833,Kallholn.D-E .Isorthoceras

ef elongatocinctum (Portloek, 1843), Kallholn. D. PMU 26814, juvenile growth stage. E. PMU 26825,

larger speeimen with irregularly spaeedtransverse ornamentation. E. Isorthoceras curvilineatum sp. nov.,

PMU 26787, holotype, Osmundsberget. G. Isorthoceras angelini sp. nov., PMU26774, holotype, Kallholn.

H. Geisonocerasl sp., PMU 26758, Kallholn. I. Isorthoceras heroyense (Strand, 1934) eomb. nov.,

PMU 26831, Kallholn. Seale bars: A= 10 mm; B-I = 10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

diameter; siphunele eeeentrie; siphuneular segments subtubular, slightly expanded within ehambers;

siphuneular diameter 0.14-0.2 of eorresponding eoneh eross seetion; septal neeks moderately long,

suborthoehoanitie; endosiphuneular deposits eonsisting of small annuli, restrieted to the apieal portions

of the phragmoeone; eameral deposits well developed. (Adopted from Frey 1995.)

Remarks

In the original diagnosis, the septal neeks were deseribed as “orthoehoanitie”, but this is impreeise; the

figures of the type speeies in Frey (1995: pl. 3, figs 4, 5, 8) indieate suborthoehoanitie septal neeks.

Ordogeisonoceras foerstei (Strand, 1934) eomb. nov.

Figs 13H, 19E

Geisonoceras foerstei Strand, 1934: 13, pl. 3, fig. 9.

Diagnosis

Slender orthoeones with apieal angle less than 5°, slightly eompressed to eireular eoneh eross seetion;

ornamented with slightly oblique transverse striae, whieh are slightly imbrieated in direetion of growth,

distanee between lirae variable, but generally less than one millimeter; siphunele eeeentrie with SPR of

ea. 0.21; siphunele diameter ea. 0.1 of eorresponding eoneh eross seetion. (Adopted from Strand 1934.)

Type locality and horizon

Frognoya Island, Ringerike, Norway; exaet stratigraphie horizon unknown. Late Ordovieian.

Material examined

One speeimen from Unskarsheden, Dalama (PMU 26759); eight speeimens from Kallholn, Dalama

(PMU 26760-26767); all from Boda Limestone, late Katian.

Description

Speeimen PMU 26763 is a portion of phragmoeone ea. 50 mm long, with a eoneh height of 34-37 mm

(angle of expansion 2.9°). The eoneh surfaee is ornamented with slightly oblique (angle of ea. 15° to the

normal of the eoneh axis) transverse lirae with a frequeney of ea. 4 per millimeter (Fig. 19E). The lirae

slope in adapieal direetion toward the prosiphuneular side, forming a shallow sinus on the prosiphuneular

side. The lirae are rounded and slightly imbrieate in an adoral direetion. The septa are direetly transverse

and ea. 20 mm apart (0.54 of eorresponding ehamber height) with a eonvexity of 13 mm (ea. 0.35 of

eorresponding eoneh height). The septal neeks are orthoehoanitie to suborthoehoanitie, ea. 3 mm long

(Fig. 13H). The siphuneular diameter is ea. 3.5 mm at the septal foramen and the eonneeting rings are

nearly tubular. No endosiphuneular or eameral deposits oeeur.

Amongst the speeimens from the Boda Limestone, several are of a relatively large size. The largest

fragment, PMU 26760, is a nearly eomplete fragment of a body ehamber with a diameter inereasing

from 115 to 145 mm and a length of 444 mm.

The shape of the eoneh eross seetion varies slightly between the speeimens from eireular to slightly

eompressed (minimum width/height ratio 0.97). The position of the siphunele is highly eeeentrie in all

speeimens, but varies between SPRs of 0.13 and 0.25, with a tendeney to shift toward the eenter during

growth.

KROGER B., Cephalopods of the Boda Limestone

The total length of the body ehamber of 150 mm is preserved in speeimen PMU 26761, whieh is 40 mm

in diameter at the last septum and 48 mm at the aperture (angle of expansion 3.1°). In this speeimen the

distanee of the transverse lirae is relatively wide, varying from 0.5 to ea. 0.8 mm.

Details of the siphunele and septal neeks are preserved in speeimen PMU 26763 (Fig. 13H); a portion

of phragmoeone is 35 to 37 mm in diameter. The septa of this speeimen are erushed and only parts of

the siphunele and septal neeks are preserved. The septal neeks are orthoehoanitie at the side direeted

toward the eoneh margin and suborthoehoanitie at the side direeted toward the eoneh eentre and very

short (ea. 0.1 of the length of the eorresponding siphuneular segment = ehamber height). Weak episeptal

deposits oeeur.

Remarks

The type speeimen eonsists of a body ehamber only. The speeimens from the Boda Limestone are

similar to the type speeimen in possessing a slightly oblique, imbrieated transverse ornamentation, a

similar eoneh eross seetion, as well as a similar siphunele diameter and position. Consequently, they are

here assigned to O. foerstei eomb. nov. The Boda speeimens reveal a suborthoehoanitie septal neek and

a nearly tubular shape of the siphunele, whieh are diagnostie eharaeters of Ordogeisonoceras.

Comparison

The type of the genus differs from O. foerstei eomb. nov. in having periodieally alternating distanees

between the transverse lirae.

Michelinocerasl expansum Blake, 1882 from the late Katian Killey Bridge of Ireland (Evans 1993) is

similar in having a slightly oblique transverse ornamentation with ea. four lirae per one millimeter. It

is probably eonspeeifie with O. foerstei eomb. nov. But the internal eharaeters are too poorly known in

order to synonymize O. foerstei with this speeies.

Geisonoceras fastis Barskov, 1980 from the latest Ordovieian of Kazakhstan, whieh is similar in general

eoneh shape and ornamentation, differs in having a eentrally positioned siphunele and shorter, more

eurved septal neeks.

Stratigraphic and geographic range

Late Ordovieian, Ringerike Distriet, Norway (Strand 1934); Boda Limestone, Siljan Distriet, Sweden;

late Katian, Ordovieian.

Genus Pleurorthoceras Flower, 1962

Type species

Orthoceras clarksvillense Foerste, 1924 from the Waynesville Formation, latest Katian of Clarksville,

Ohio, USA.

Diagnosis

Slender, gradually expanding, smooth orthoeones; eireular in eross seetion with straight, transverse

sutures; ehamber distanee between one-third to one half of the eorresponding eoneh diameter, siphunele

subeentral to eentral; siphuneular segments subtubular, slightly expanded within ehambers; septal neeks

short, suborthoehoanitie; endosiphuneular deposits unknown; mural eameral deposits well developed.

(Adopted from Flower 1962.)

European Journal of Taxonomy 41: 1-110 (2013)

Pleurorthoceras osmundsbergense sp. nov.

um:lsid:zoobank.org:act:C6C26456-C557-45FD-BBB8-E2BFClC0300C

Figs 13G, 14C, 18E, 23A, 24

Diagnosis

Pleurorthoceras with very slightly curved shell, with angle of expansion of ca. 7°, circular conch cross

section, and adult diameters of ca. 50 mm; ornamented with fine, inconspicuous, irregularly spaced,

slightly oblique growth lines or rounded striae; siphuncle subcentral (SPR ca. 0.46) on convex side of

conch curvature. Heavy mural deposits.

Etymology

Refers to the type locality.

Type material

Holotype

NRMMo 150126.

Paratypes

Two paratypes: NRM Mo 150102 from Osmundsberget, Dalama; PMU 26768 from Kallholn, Dalama,

Sweden; all Boda Eimestone, Boda Core Member, late Katian.

Type locality and horizon

Osmundsberget, Siljan District, Sweden, Boda Eimestone, Boda Core Member, late Katian, Ordovician.

Fig. 24. Polished median section (left) and interpretation (right) of Pleurorthoceras osmundsbergense

sp. nov., NRM-PZ Mo 190102c, Osmundsberget, Boda Eimestone. Dark grey = episeptal and hyposeptal

(primary?) deposits; light grey = mural (secondary?) deposits. Scale bar =10 mm.

KROGER B., Cephalopods of the Boda Limestone

Other material examined

An additional 43 non-type speeimens from Osmundsberget are in the eolleetions of the NRM.

Description

The holotype is a nearly eomplete speeimen with a length of 280 mm, with a diameter of 15^8 mm

(angle of expansion 6.7°) and a very slightly eurved eoneh (Figs 18E, 23A). The angle of expansion

deereases with size to form a nearly tubular adult body ehamber. The shell surfaee is nearly smooth, but

fine, irregularly spaeed, rounded striae run obliquely transverse, forming a shallow sinus on the eoneave

side of the eoneh eurvature.

In speeimen NRM Mo 150102, whieh is a fragment of a juvenile phragmoeone with a length of 105

mm and a diameter of 22-37 mm (angle of expansion 8.1°), the distanee between septa is 0.24-0.36 of

the eorresponding eoneh eross seetion. The siphunele is nearly eentral in apieal parts, beeoming more

eeeentrie at adoral parts (SPR 0.46). The siphuneular segments are barrel-shaped, slightly expanded

within the ehambers, with a maximum siphunele diameter of 3 mm at septal foramen at a eoneh eross

seetion diameter of 22 mm (0.14 of eoneh eross seetion). The septal neeks are suborthoehoanitie (Figs

13G, 14C). No endiphuneular deposits oeeur, and remains of heavy mural eameral deposits are preserved

in the apieal parts of the fragment (Fig. 24).

Comparison

Pleurorthoceras osmundbergense sp. nov. differs from the genotype and the seeond North Ameriean

speeies, P. selkirkense (Whiteaves, 1892) in having a signifieantly higher angle of expansion and a

slightly eurved growth axis. P. subcostatum (Portloek, 1843) from Killey Bridge Formation, latest

Katian (Evans 1993), differs in having a distinet retieulate ornamentation.

Stratigraphic and geographic range

Boda Limestone, Siljan Distriet, Sweden; late Katian, Ordovieian.

Family Proteoeeratidae Flower, 1962

Genus Gorbyoceras Shimizu & Obata, 1935

Type species

Orthoceras gorbyi Miller in Miller & Faber, 1894, probably from the Saluda Formation, latest Katian,

Franklin County, Indiana, USA; by original designation.

Diagnosis

Slender, eireular or slightly eompressed orthoeones with symmetrieally eurved septa and straight

transverse sutures; sutures parallel to annulations in eaeh groove of the annulations; annulations with

fine transverse ornament or growth lines; annulations more distinetive in adult growth stages; distinetive

irregularly spaeed longitudinal ridges that may form nodes at the ridges of the annulations; siphunele

subeentral, expanded in early growth stages, with short eyrtoehoanitie septal neeks, nearly tubular in

later growth stages, with suborthoehoanitie septal neeks; mural eameral deposits developed mueh farther

anteriorly than endosiphuneular deposits. (Adopted from Sweet 1964e; Kroger & Isakar 2006.)

Remarks

A large number of speeies of Gorbyoceras exist, whieh are in need of a revision. Potentially most of the

Late Ordovieian North Ameriean speeies of Spyroceras Hyatt, 1884 belong to Gorbyoceras, but their

European Journal of Taxonomy 41: 1-110 (2013)

internal characters are not yet described. Additionally, often the ontogenetic variability in ornamentation

is poorly known. Evans (1993) synonymized a number of Late Ordovician species with the aspect

of Gorbyoceras from Ireland within G. gracile (Portlock, 1843) and suggested that the number and

strength of the longitudinal lirae are ontogenetically highly variable. Among the material assigned

within G. gracile by Evans (1993) and listed in Evans (his table 5), not a single specimen shows any

similarity with the material from the Boda Limestone. The specimens described by Evans (1993) may

represent different species, but none of them can by synonymized with the Boda species of Gorbyoceras

or Dawsonoceras.

Gorbyoceras alternestriatum (Strand, 1934) comb. nov.

Figs 16F, 17F

Spyroceras alternestriatum Strand, 1934: 19, pi. 3, figs 5, 6.

Gorbyoceras sp. -Dzik 1984: 122, text-fig. 48d, pi. 35, fig. 1.

Emended diagnosis

Gorbyoceras with slightly cyrtoconic adult body chamber, shell slightly compressed, relatively large

adult size of more than 50 mm in conch height; slightly irregularly spaced, pronounced rounded

annulations, approximately five to six in a length equal to conch diameter; approximately 30 regularly

spaced longitudinal lirae around the entire circumference; in interspaces between primary lirae one or

two less pronounced secondary lirae occur, approximately 12-15 fine transverse angular lirae between

two successive ridges of annulations; sutures straight, nearly transverse, one suture at each groove of the

annulations. Siphuncle eccentric in juvenile, subcentral in more adult growth stages, septal perforation

approximately one tenth of the diameter of the shell.

Type locality and horizon

Stavnestangen, Ringerike District, Norway, Bonsnes Formation, latest Katian, Late Ordovician.

Material examined

Two specimens (PMU 26769, 26770), Kallholn; one specimen (PMU 26771), Unskarsheden, Siljan

District, Sweden; Boda Limestone, Boda Core Member, late Katian, Ordovician.

Description

Specimen PMU 26771 is a nearly complete body chamber of a mature individual with a length of 90 mm

and an adoral conch height of 51 mm and 47 mm at the apical end of the specimen (angle of expansion

2.5°) (Fig. 16F). The conch cross section is slightly compressed with ratio of the width to height of 0.91.

The conch is slightly curved with the siphuncle, eccentric (SPR 0.34) on the convex side of the conch

curvature. The septal perforation is 3 mm wide (0.06 of conch height). The septum at the base of the

body chamber is shallow, with a depth of 10 mm (0.21 of conch height). The shell is annulated with

slightly irregularly spaced and irregularly elevated rounded elevations; ca. six occur in a length equal to

conch diameter. Around the circumference ca. 32 regularly spaced, distinctly raised primary lirae occur.

In the interspaces one slightly less pronounced longitudinal raised line occurs. Additionally the conch

is ornamented with fine, angular transverse lirae, 12-15 occurring between two successive ridges of the

annulations, generating a fine reticulate pattern (Fig. 17F).

The two other specimens consist of portions of phragmocone with diameters from 18 to 22 mm, and

from 22 to 23 mm respectively, with angles of expansion of ca. 8°. The distance between two successive

KROGER B., Cephalopods of the Boda Limestone

annuli is ea. 0.18 of the eorresponding eoneh eross seetion. The eross seetion is nearly eireular. In

speeimen PMU 26769 the distanee between the ehambers is 0.18, and the suture lies in the groove of

the annulation. The surfaee of this speeimen is ornamented with 32 and 28 primary lirae, respeetively.

Between the primary lirae, one or two less pronouneed seeondary lirae oeeur.

Remarks

The speeimens deseribed above are assigned to Gorbyoceras alternestriatum (Strand, 1934) eomb. nov.,

beeause they agree in detail with the speeimens deseribed by Strand (1934) from the Bonsnes Formation

of Norway. The new data, available from the adult body ehamber PMU 26771, and additional data

regarding the internal eharaeters permit a more detailed speeies diagnosis and emendation.

Comparison

This speeies is very similar to G. textumaraneum (Roemer, 1861) eomb. nov. Both speeies have relatively

large (more than 40 mm in eoneh diameter), eurved adult body ehambers, eombined with a relatively

widely spaeed retieulate ornamentation. G. alternestriatum eomb. nov. differs from the latter mainly in

having a primary and seeondary longitudinal ornamentation.

G. tetreauense Wilson, 1961 from the late Katian, Ottawa Formation, Canada is similar with respeet

to the angle of expansion and general aspeets of ornamentation, but differs in having a more eurved,

stronger expanding eoneh with less pronouneed annulations.

Stratigraphic and geographic range

Bonsnes Formation, latest Katian, Stavnestangen, Ringerike Distriet, Norway (Strand 1934); latest

Katian, erratie boulder, Mi^dzyzdroje, Poland (Dzik 1984); Boda Limestone, Boda Core Member, late

Katian, Silj an Distriet, Sweden.

Gorbyoceras sp. A

Figs 16C, 17C

Material examined

Speeimen PMU 26772 from Osmundsberget, Siljan Distriet, Sweden; Boda Limestone, Boda Core

Member, late Katian.

Description

A fragment of a eoneh ea. 22 mm long, with a diameter inereasing from 22 to 25 mm (angle of expansion

ea. 6°). No internal struetures are preserved (Fig. 16C). The shell is strongly annulated and exhibits four

annuli that show varying amplitudes (maximum amplitude of 1.5 mm). About 16 pronouneed primary

lirae are present around the eireumferenee; between eaeh pair, three to four less pronouneed, irregularly

spaeed seeondary striae oeeur (Fig. 17C). About ten transverse lirae are present in a length equal to one

eyele of annulation.

Remarks

This small annulated fragment with its 16 primary and more than 48 seeondary longitudinal lirae

is uniquely ornamented; no Ordovieian orthoeerid with a similar ornamentation is known. The

ornamentation is most similar to speeies of Gorbyoceras and the speeimen is interpreted as a new

speeies of Gorbyoceras. However, this poorly preserved speeimen does not provide suffieient data to

justify the ereetion of a new speeies.

European Journal of Taxonomy 41: 1-110 (2013)

Gorbyoceras sp. B.

Fig. 16D

Material examined

One specimen (PMU 26773), Kallholn, Siljan District, Sweden; Boda Limestone, Boda Core Member,

late Katian.

Description

Specimen PMU 26773 is a diagenetically deformed and fragmented part of a body chamber and

phragmocone 52 mm long and 43 mm in diameter (Fig. 16D). Apically a relatively deep septum is

preserved (depth of curvature 8 mm, 0.19 of conch height). The position and size of the siphuncle cannot

be determined.

The shell is annulated, with distance between annuli of ca. 11 mm (0.26 of conch cross section, ca. five

annuli per distance equal to conch diameter). The shell is 2.1 mm thick at the culminations of the annuli,

and 0.5 mm thick on the fioors in between. As a consequence of the zones with thickened shell, the surface

of the shell is strongly annulated with sharply rounded ridges, while the internal mould is only weakly

annulated with much shallower ridges. The shell surface is ornamented with longitudinal lirae, but the

preservation of the shell is too poor to conserve the details of the pattern of the ornamentation.

Remarks

This strongly annulated fragment displays a longitudinal ornamentation which is characteristic of

Gorbyoceras. However, because details of the ornamentation, such as the number of primary and

secondary lirae, are not preserved a species level determination is impossible. This specimen differs from

known late Ordovician species of Baltoscandia in the exceptionally high amplitude of the annulations

combined with the large diameter of the conch.

Genus Isorthoceras Flower, 1962

Type species

Orthoceras sociale Hall in Miller, 1877, from the Elgin Member, Maquoketa Formation, latest Katian,

Graf, Iowa, USA; by original designation.

Diagnosis

Orthoconic longicones with subcircular cross section and subdued ornamentation, smooth or with

fine transverse and/or longitudinal lirae. Siphuncle subcentral, with barrel-shaped early segments and

subcylindrical later segments. Septal necks suborthochoanitic-cyrtochoanitic. Endosiphuncular annuli

grow forward andbackward, j oining those ofadj acent segments to form continuous parietal lining ofuniform

thickness throughout segments. Mural to episeptal cameral deposits. (Adopted from Flower 1962 and

Frey 1995.)

Isorthoceras angelini sp. nov.

um:lsid:zoobank.org:act:D60B4D34-B324-4F4B-817D-2EBElF0F09BA

Figs 13D, 14D, 17H, 23G, 25

Diagnosis

Isorthoceras with weakly curved conch with circular or slightly compressed cross section; angle

of expansion decreases with conch size, ca. 7-9° in premature growth stages; ornamented with fine

longitudinal raised lirae and irregularly spaced transverse lirae; transverse lirae form shallow sinus on

KROGER B., Cephalopods of the Boda Limestone

eoneave side of eoneh eurvature; eoneh very weakly, irregularly undulated; mature size ea. 15 mm;

position of siphunele subeentral in early growth stages and eeeentrie at eonvex side of eoneh eurvature

in late growth stages, septal neeks are suborthoehoanitie-eyrtoehoanitie.

Etymology

In honour of Nils Peter Angelin (1805-1876), a Swedish geologist and paleontologist, for his pioneering

work on the Swedish palaeozoie fossils (e.g., Angelin & Lindstrom 1880).

Type material

Holotype

PMU 26774.

Paratypes

Twelve paratypes: PMU 26775-26786, Kallholn, Dalama, Boda Limestone, latest Katian.

Type locality and horizon

Kallholn, Siljan distriet, Dalama, Sweden; Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype, PMU 26774, is a 40 mm long fragment of a phragmoeone with a eireular eross seetion

and a diameter whieh is 5.8-9 mm of a length of 30 mm (angle of expansion 9.1) (Fig. 23G). The

Fig. 25. Variability of the angle of expansion in fragments of different diameters of Isorthoceras angelini

sp. nov. Note the tendeney of deereasing angle of expansion with diameter. The adult diameter is reaehed

at ea. 15 mm.

European Journal of Taxonomy 41: 1-110 (2013)

conch is ornamented with fine raised longitudinal lirae, whieh have a distanee of ea. 0.2 mm, and with

transverse lirae, whieh have a distanee of 0.1 mm. The spaeing of both the longitudinal and transverse

lirae is slightly variable. Additionally, the surfaee of the shell undulates slightly, with a varying distanee

of ea. 2 mm. The transverse ornamentation forms a very shallow sinus on the eoneave side of the eoneh

eurvature. The eoneh is very slightly eurved with the siphunele eeeentrie to subeentral in position. It

shifts slightly to the eonvex side of the eoneh eurvature during the growth of the organism. At the apieal

end of the fragment, the smallest distanee of the siphunele from the eoneh margin is 2.7 mm (SPR 0.46)

and the ehamber height is 3 mm (ea. 0.5 of eorresponding eoneh height).

The details of the siphunele and septal neeks are seen in PMU 26784, a portion of phragmoeone,

inereasing in diameter from ea. 6.8 to 8.7 mm (Figs 13D, 14C). At the adapieal end of the speeimen

the siphunele is 1.9 mm from the eoneh margin (SPR 0.28) and the distanee between septa is 2.9 mm

(0.43 of eorresponding eoneh eross seetion). The siphunele is nearly tubular, with very slightly infiated

eonneeting rings. It has a diameter of 0.15 of the eorresponding eoneh eross seetion. The septal neeks

are very short, poorly preserved, and appear to be suborthoehoanitie or eyrtoehoanitie. Episeptal and

mural deposits oeeur (Figs 13D).

The nine available measurements of angles of expansion reveal a elear tendeney of deereasing angle

of expansion with inereasing eoneh size. The maximum values are reaehed by the fragment of the

leetotype, the average is 7.1° and the smallest measurements are on the speeimen with a maximum

diameter of 15 mm (PMU 26786, Fig. 25).

PMU 26785 and 26786 are the largest fragments, both eonsisting of parts of body ehambers that are

nearly tubular. The ornamentation of these fragments is eharaeterized by longitudinal and transverse

lirae and a very shallow, irregular undulation. Pronouneed, irregularly spaeed growth lines also oeeur.

Comparison

This speeies of Isorthoceras is unique beeause of its eombination of a relatively small adult size of only

15 mm, its angle of expansion of 7-9° and its eeeentrieally positioned siphunele.

A very similar, yet undeseribed speeies oeeurs in the Kullsberg Limestone, early-mid Katian of

Dalama, Sweden. This speeies differs from I. angelini sp. nov. in having a more pronouneed transverse

ornamentation.

A retieulate ornamentation oeeurs also in Orthoceras lepteanarum Angelin in Angelin & Lindstrom,

1880, a speeies whieh is known from a single speeimen (NRM Mo 152344) from the Boda Limestone

of Ostbjorka. This speeimen is a poorly preserved small fragment of a phragmoeone with a diameter of

38 mm. It is very likely to represent a speeies of Isorthoceras and may be elosely related or eonspeeifie

with Isorthoceras tenuitextum (Hall, 1847). The ornamentation in NRM Mo 152344 is partly preserved

and eonsists of elevated, irregularly spaeed, longitudinal and transverse lirae. The distanee between the

longitudinal striae (ea. 1.5 mm) is eonsiderably larger than that of the transverse elements, resulting in a

surfaee pattern of minute transverse reetangles. Compared with/, angelini sp. nov., the longitudinal striae

are signifieantly more widely spaeed, both in absolute dimensions (more than 1 mm in O. lepteanarum

against ea. 0.1-0.2 mm in I. angelini sp. nov.) and in relative dimensions (more than 5 transverse lirae

oeeur per distanee similar to the distanee of two longitudinal striae in I. (?) lepteanarum eomb. nov.

against ea. 1.5-2 in/, angelini sp. nov.).

Isorthoceras tenuitextum (Hall, 1847), whieh is eommon in late Katian sediments of Eastern Laurentia,

is similar in ornamentation, but differs in having an adult size of more than 25 mm and a less, but more

eonsistently expanding eoneh with an angle of expansion of ea. 6°.

KROGER B., Cephalopods of the Boda Limestone

Isorthoceras alter si (Miller & Faber, 1894), whieh is the most eommon speeies within the Lexington

Limestone, Kentueky, USA (see Frey 1995: 60), has a similar ornamentation and angle of expansion, but

differs in having a larger adult size.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Isorthoceras curvilineatum sp. nov.

um:lsid:zoobank.org:aet:7BlFQ9EA-8B80-44EC-8F8Q-7EQEDD3F4E3D

Figs 17G, 23F

Diagnosis

Transversally ornamented, strai^t Isorthoceras with eireular eross seetion and low angle of expansion of

less than 2°. Ornamented with ea. ten rounded transverse striae per millimetre, whieh form eharaeteristie

shallow hyponomie sinus with two direetly adjaeent shallow salients. Adult size elearly less than ea. 10

mm in eross seetion. Siphunele eentral with diameter ea. 0.1 of eoneh eross seetion.

Etymology

Refers to the eonspieuously eurved transverse ornamentation of this speeies.

Type material

Holotype

PMU 26787.

Paratypes

Two paratypes: PMU 26788 and 26789, Osmundsberget, Siljan Distriet, Sweden; Boda Limestone,

Boda Core Member, late Katian, Ordovieian.

Type locality and horizon

Osmundsberget, Siljan Distriet, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

Three speeimen from Osmundsberget (PMU 26787-26789) are very similar to eaeh other, with a very

low angle of expansion of less than 2°, eoneh diameters between 6 and 8 mm and a very fine transverse

ornamentation, with ea. ten rounded striae per millimetre (Fig. 17G). The striae are laterally slightly

oblique, and form a shallow hyponomie sinus with two direetly adjaeent shallow projeetions on the left

and right side.

The holotype is a fragment of parts of a phragmoeone and body ehamber with a length of 35 mm and a

diameter of 6.2-7.2 mm (angle of expansion 1.6°) (Fig. 23F). The siphunele is eentral, with a diameter

of the septal perforation of 0.6 mm at the apieal end of the fragment. The length of the body ehamber

eannot be measured, beeause no traees of septa are visible in the middle parts of the holotype.

Remarks

A very small adult size of less than 10 mm is assumed for this speeies, based on the very low angle of

expansion, whieh is only 0.7° in the largest speeimen, with a maximum diameter of 7.5 mm.

This speeies is assigned within Isorthoceras beeause the general eoneh shape is very similar to other

small speeies of Isorthoceras, sueh/. angelini sp. nov. However, some uneertainty remains in the generie

assignment, beeause the internal eharaeters are not known. A similar narrow, transverse ornamentation

European Journal of Taxonomy 41: 1-110 (2013)

is known from Isorthoceras elongatocinctum (Portlock, 1843) comb, nov., which differs in having a

directly transverse striation.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Isorthoceras dalecarlense Kroger et al, 2011

Figs 4B, 26

Isorthoceras dalecarlense Kroger et a/., 2011: 45, fig. 9e, g.

Diagnosis

Smooth, nearly straight Isorthoceras with eireular eross seetion and eomparatively low angle of

expansion of 6°, ehamber distanee 0.3 of eorresponding eross seetion, depth of septal eurvature ea. 0.26 of

eorresponding eross seetion. Adult size >35 mm in eross seetion. Siphunele eeeentrie in early, subeentral

conch diameter in mm

Fig. 26. Variability of the angle of expansion in fragments of different diameters of Isorthoceras

wahlenbergi Niko, 2008 (blaek points) and Isorthoceras dalecarlense Kroger et al, 2010 (grey points).

The blaek eireles refer to speeimens figured in Kroger et al. (2011: fig. 11) and identified as I. dalecarlense,

therein. The eomplete dataset, presented herein, demonstrates that a definite speeies distinetion by angle

of expansion and size alone is impossible in fragmentary speeimens with angles of expansion between

6° and 8°. Additionally, the eomplete dataset reveals that speeimens with eoneh diameter > 7 mm and

angle of expansion > 8° in Kroger et al. (2011: fig. 11) must eorreetly be interpreted as fragments of

I. wahlenbergi.

KROGER B., Cephalopods of the Boda Limestone

in later growth stages, siphuneular segments slightly expanded within ehambers with diameter ea. 0.1 of

eoneh eross seetion. Septal neeks short, on border-line between eyrtoehoanitie and suborthoehoanitie.

In apieal parts of siphunele thin parietal deposits that ventrally fuse to irregular endosiphuneular lining

at extreme apieal part of eoneh. Cameral deposits not known.

Type locality and horizon

Osmundsberget quarry, Rattvik Munieipality, Siljan Distriet, Sweden (loeality Osmundsberget 1 of

Ebbestad & Hogstrom 2007); nautiloid bed, top of Glisstjam Formation, Himantian, Late Ordovieian.

Material examined

Nineteen speeimens (PMU 26790-26808) from Kallholn, Siljan Distriet, Sweden; Boda Limestone,

latest Katian, Ordovieian.

Comparison

The speeies was deseribed in detail by Kroger et al. (2011). Here, details of the variability of the external

eoneh features ean be added. Fourteen speeimens are assigned to this speeies. They are similar in all

aspeets to I. wahlenbergi Niko, 2008, but differ from the type of /. wahlenbergi in having a signifieantly

lower angle of expansion.

The angle of expansion varies strongly within the smooth Boda Limestone speeimen of Isorthoceras

(Fig. 26). A slender form (/. dalecarlense) and a wide angled variety (/. wahlenbergi) ean be distinguished

(eompare Fig. 4B, and 4C). But the distinetion is eomplieated by the ontogenetie ehange of angle of

expansion in both varieties. In both varieties the angle of expansion is initially low, reaehes maximum

values in premature growth stages and deelines in fragments of the mature body ehamber.

Nevertheless, in the eoneh size/angle of expansion-plot (Fig. 26) two groups ean be distinguished in

eaeh individual growth seetion, but not in juveniles and mature speeimens. This overlapping in the plot

is an effeet of the method of measurement, whieh does not distinguish between long and short fragments

(the angle of expansion is measured in fragments with different lengths). Thus, in smaller fragments

of juvenile and mature eonehs a distinetion between the two speeies is impossible, but longer eoneh

fragments will always reveal a strong differenee in intermediate growth stages.

As a result of these measurements it is elear that some of the speeimens measured by Kroger et al.

(2011: fig. 10) represent/, wahlenbergi. Consequently, I. wahlenbergi also oeeurs within the Himantian

Glisstjam Formation (see Fig. 26).

Balashov (1975) deseribed smooth, slender orthoeerids from the Molodov Horizon of Podolia as

Michelinoceras dnestrovense. The shape of the septal neeks and the siphuneular segments, as well as the

ehamber spaeing indieate that these speeimens are better assigned to Isorthoceras. The ehamber spaeing

of the figured speeimen of/, dnestrovense (Balashov, 1975) eomb. nov. varies from 0.17 to 0.2 and thus

is eonsiderably narrower than in I. dalecarlense.

Stratigraphic and geographic range

Boda Limestone, Glisstjam Formation, late Katian-Himantian, Dalama, Sweden (see diseussion of

/. dalecarlense, above).

Isorthoceras cf. elongatocinctum (Portloek, 1843) eomb. nov.

Figs 17A, D, 23D-E, 27

Orthoceras elongato-cinctum Portloek, 1843: 372, pi. 27, fig. 2a-b.

European Journal of Taxonomy 41: 1-110 (2013)

Orthoceras elongato cinctum - Bm\y 1875: pi. 12, fig. 10 (non pi. 13, fig. 8; see diseussion below).

Orthoceras elongatocinctum - Blake 1882: 119, pi. 13, figs 7, 8, 8a. — Evans 1996: 118, pi. 21, figs 1,

2, text-fig. 21f.

Geisonocerina elongatocinctum - Holland 1993: 39, text-fig. Ig, i; 2000: 181, text-fig. Im.

Orthoceras aff. elongatocinctum -E\ans 2002: 81, pl. 1, figs 1-3.

Diagnosis

Transversally ornamented, straight Isorthoceras with eireular eross seetion and eomparatively low angle

of expansion of ea. 4°, ehamber distanee 0.3-0.4 of eorresponding diameter; transverse ornamentation

eonsists of distinetly elevated, sharp, sometimes imbrieate lirae, with distanee of ea. six to ten per

millimetre; siphunele nearly eentral with diameter ea. 0.1 of eorresponding eoneh diameter. (Adopted

from Holland 1993; Evans 1993.)

Type locality and horizon

Killey Bridge Formation, County Tyrone, Northern Ireland. Katian Stage.

Material examined

Twenty-two speeimens, one (PMU 26809) from Osmundsberget; 20 from Kallholn, Siljan distriet,

Sweden (PMU 26810-26829); all Boda Eimestone, Boda Core Member, late Katian, Fate Ordovieian.

One additional speeimen (PMU 26830) from mid Katian Kullsberg Eimestone, Kullsberg, Siljan distriet,

Sweden.

Description

Speeimen PMU 26825 is a portion of the phragmoeone and a nearly eomplete mature body ehamber, with

a diameter inereasing from 8 to 13 mm and a length of 75 mm (angle of expansion 3.8°). It is ornamented

Fig. 27. Angle of expansion of 15 measured speeimen of Isorthoceras ef elongatocinctum (Portloek,

1843), Boda Eimestone, Fate Katian, Dalama, Sweden.

KROGER B., Cephalopods of the Boda Limestone

with sharp, distinetly raised lirae; apieally with ea. four to five lirae per millimetre. Adorally the lirae

are inereasingly more erowded and irregularly spaeed, with ea. ten per millimetre near the aperture. The

lirae are slightly oblique and form a distinet, but shallow hyponomie sinus on the antisiphuneular side of

the eoneh. An apertural shell thiekening and the low apieal angle indieate maturity.

When eomparing the seventeen measured speeimens, a elear trend of deereasing angle of expansion

beeomes apparent (Fig. 27). In early growth stages the angle is as high as 7°, but it eontinuously

deereases with inereasing eoneh diameter. The position of the siphunele is preserved in speeimens PMU

26814-26815 (SPR 0.49, 0.46), 26810 (SPR 0.4), 26823 (SPR 0.43) and 26826 (SPR 0.44). In smaller

speeimens the siphunele is more eeeentrie, but in all other speeimens it is nearly eentrally positioned.

The septal spaeing varies between 0.3 (PMU 26815) and 0.44 (PMU 26826) of the eorresponding eoneh

height.

Remarks

This speeies was previously known only from the latest Katian sediments of Northern Ireland and Wales.

Details of the internal eharaeters were deseribed by Evans (1993: fig. 8), who revised the speeies based

on more than one hundred speeimens. Evans (1993: 167) deseribed the septal neeks as orthoeonie, but

his fig. 8 shows septal neeks whieh must be termed “suborthoehoanitie” in the striet sense (see Material

and Methods, above). The shape of the septal neeks, the eonstrieted siphunele, the general eoneh shape

and the ornamentation are similar to other speeies of Isorthoceras. Based on this similarity, this speeies

is here assigned to Isorthoceras.

The largest speeimen in the Irish material has a diameter of 25 mm. The speeimens from the Boda

Limestone and the diagram in Evans (1993: fig. 9) suggest a maximum size of less than 15 mm, whieh

is the reason why the Boda speeimens are assigned with the addendum “ef ” to this speeies.

These speeimens are identieal in external eharaeters to the speeimens deseribed by Evans (1993).

Additional information on the variability of the apieal angle and the ornamentation are provided by the

speeimens from the Boda Limestone. Speeimen PMU 26825 is the most eompletely preserved fragment

and demonstrates the ontogenetie variation of the transverse ornamentation and angle of expansion (Figs

17A, D; 23D-E). The angle of expansion of mature parts of the shell is very small, and the spaeing of the

transverse lirae is narrower and more irregular in later growth stages.

Comparison

This speeies differs from other speeies of Isorthoceras in having an ornamentation of fine, but distinetly

elevated, aeute transverse lirae, ea. 0.2 to 0.1 mm distant.

Geisonoceras heintzi Strand, 1934, from the Sorbakken formation in the Ringerike Distiet, Norway,

probably represents a speeies of Isorthoceras and is a small, slender transversally ornamented form that

differs from I elongatocinctum eomb. nov. in having transverse lirae whieh are more distantly spaeed

(distanee ea. 0.4 mm). Isorthoceras heroyense (Strand, 1934) eomb. nov. is similar an ornamentation,

but differs in having a more eeeentrie siphunele (SPR 0.31) and a larger angle of expansion (5-9°).

Stratigraphic and geographic range

Kildare Limestone, Killey Bridge Formation, Portrane Limestone, late Katian, Ireland, Keisley

Limestone, late Katian, Cumbria, UK (Holland 1993; Evans 1996, 2002); Sholeshook Limestone, late

Katian, South Wales, UK (Evans 1996); lower Wether Law Linn Formation, Telyehian, Ireland (Holland

2002); Boda Limestone, late Katian, Siljan Distriet, Sweden.

European Journal of Taxonomy 41: 1-110 (2013)

Isorthoceras heroyense (Strand, 1934) comb. nov.

Figs 231, 28A

Geisonoceras heroyense Strand, 1934: 15, pi. 3; fig. 16.

Diagnosis

Transversally ornamented, straight Isorthoceras with eireular eross seetion and eomparatively low angle

of expansion of ea. 5°, ehamber distanee 0.5 of eorresponding eross seetion; transverse ornamentation

eonsists of rounded, sharp, raised lirae, with distanee of ea. six per millimetre; siphunele eeeentrie with

diameter ea. 0.13 of eoneh eross seetion. (Adopted from Strand 1934.)

Fig. 28. Color marks in Isorthoceras Flower, 1962, Boda Limestone. Longitudinal striae

of varying width oeeur in several speeimen of Isorthoceras', see text for diseussion. A.

Isorthoceras heroyense (Strand, 1934) eomb. nov., PMU 26831, Kallholn. B. Isorthoceras

suave (Angelin in Angelin & Lindstrom, 1880) eomb. nov., PMU 26835, Osmundsberget.

C. Isorthoceras wahlenbergi Niko, 2008, PMU 26862, Kallholn. Seale bar =10 mm for all figures.

KROGER B., Cephalopods of the Boda Limestone

Type locality and horizon

Heroya near Porsgmnn, Norway; Heroya Formation (“Gastropod Limestone”), late Katian, Late

Ordovieian.

Material

Two speeimens (PMU 26831, 26832) from Kallholn, Siljan Distriet, Sweden; Boda Limestone, Boda

Core Member, late Katian, Ordovieian.

Description

Specimen PMU 26831 is a fragment of a body chamber with a length of 35 mm and a diameter of 9.2-12

mm (angle of expansion 4.5°) (Figs 231, 28A). The basal septum of the body chamber is preserved, with

a convexity of ca. 3 mm and a septal perforation with a diameter of 1.5 mm (0.16 of conch cross section).

The siphuncle is positioned 2.3 mm from the conch margin (SPR 0.25). The conch is ornamented with

fine transverse lirae, ca. six in a distance of one millimetre, which are slightly oblique, projecting adorally

on the prosiphuncular side of the conch and forming shallow and wide sinus on the antisiphuncular side.

Around the circumference several brown bands are preserved (Fig. 28A). The bands are ca. 0.5 mm

wide; a number of 28 would occur around the total circumference.

Remarks

This species is assigned to Isorthoceras on the basis of the general similarity of the external conch

characters to those of other species of this genus. Nothing is known about the adult size of this species,

but the decreased angle of expansion of the two specimens from the Boda Limestone suggest an adult

size of no more than 15 mm.

Comparison

This species is most similar to I.junceum (Hall, 1847) with respect to the transverse ornamentation, but

differs in having more widely spaced transverse striae (six per millimetre in I. heroyense comb. nov.; ten

per millimetre in I.junceum) and a higher angle of expansion at similar conch diameters. The strongly

eccentric siphuncle is unique amongst known species of Isorthoceras.

Stratigraphic and geographic range

Heroya near Porsgmnn, Norway, Heroya Formation (“Gastropod Limestone”), Frognoya Island,

Ringerike, Norway, Bonsnes Formation (Strand 1934); Boda Limestone, Siljan District, Sweden; all

late Katian, Late Ordovician.

Isorthoceras junceum (Hall, 1847)

Figs 17E, 23C

Orthoceras junceum Hall, 1847: 204, pi. 47; fig. 3a-f

Geisonoceras - Balashov 1956: 199, pi. 4, fig. 4a-b.

Isorthoceras? junceum - Kroger et al. 2011: 46, figs 4a, 9h-i (with synonymy).

Diagnosis

Transversally ornamented, straight Isorthoceras with circular cross section and comparatively low angle

of expansion of 5°, chamber distance 0.2-0.3 of corresponding cross section; adult size ca. 10-11 mm in

cross section; siphuncle subcentral-central with diameter ca. 0.1 of corresponding conch cross section.

(Compiled from Hall 1847.)

European Journal of Taxonomy 41: 1-110 (2013)

Type locality and horizon

Watertown, New York, USA; Trenton Formation, early Katian, Late Ordovieian.

Material

Two speeimens (PMU 26833, 26834) from Kallholn, Siljan Distriet, Sweden; Boda Limestone, late

Katian, Ordovieian.

Description

Specimen PMU 26833 is a fragment of a body chamber 40 mm long, with a diameter increasing from

11 to 12.8 mm (angle of expansion 2.6°). At the adoral end of the specimen, the cast possesses a ca. 3

mm wide apertural constriction, which indicates a mature apertural shell thickening. The shell surface is

ornamented with ca. ten fine rounded transverse striae per millimetre.

The second specimen is a 44 mm long portion of a phragmocone, with a diameter increasing from 6.2 to

8.8 mm (angle of expansion 3.4°) and a central thin siphuncle (Figs 17E, 23C).

Remarks

The two specimens are assigned to I. junceum based on the general similarity of the conch dimensions,

the low angle of expansion, and the characteristic narrow transverse ornamentation. The adult conch

diameter of specimen PMU 26833 is slightly larger than in other specimens of this species, which is

interpreted as intraspecific variation.

The species was discussed in detail by Kroger et al. (2011). Herein the question mark that was positioned

after the genus name by Kroger et al. (2011) is omitted, because a comparison of known species of

Isorthoceras clearly indicates that this genus is characterized by the typical conch features that are listed

above. The internal characters of the type of this species are still not known, but the external features are

so similar to those of other species of the genus, that it justifies assigning O. junceum to Isorthoceras.

Comparison

Isorthoceras romingeri (Foerste, 1932) is a finely transversely strmtQd Isorthoceras from the Black River

Formation of Minnesota, USA, which differs in having a larger adult size (more than 17 mm in cross

section) and a narrower chamber spacing (seven chambers occur per distance similar to corresponding

cross section).

Stratigraphic and geographic range

Trenton Limestone, early Katian, from New York, USA (Hall 1847); Rocklandian-Edenian, mid Katian,

from north central USA (Catalan! 1987); Martinsburg Shale, late Katian (Bassler 1919); Utica Shale,

late Katian (Flower 1946); Anderskyi bed, southern Kazakhstan, late Katian (Balashov 1956); Boda

Eimestone, late Katian-Glisstjam Formation, Himantian, Siljan District, Sweden.

Isorthoceras suave (Angelin /fr Angelin & Eindstrom, 1880) comb. nov.

Figs 171, 23B, 28B

Orthoceras suave Angelin /fr Angelin & Eindstrom, 1880: 3, pi. 7, figs 13-17.

Diagnosis

Isorthoceras with weakly curved conch and circular or slightly compressed cross section; angle of

expansion ca. 9° in premature growth stages; ornamented with fine longitudinal raised lirae and faint

KROGER B., Cephalopods of the Boda Limestone

transverse irregularly spaeed growth lines; mature size more than 20 mm; siphunele eeeentrie to

subeentral at eonvex side of eoneh eurvature.

Type material

Lectotype

NRM-Mo 151187 (Angelin & Lindstrom 1880: pi. 7, figs 16-17) (designated herein).

Paralectotype

NRM-Mo 151186 (Angelin & Lindstrom 1880: pi. 7, fig. 14).

Type locality and horizon

Ostbjorka, Siljan distriet, Dalama, Sweden; Boda Limestone, Boda Core Member, late Katian,

Ordovieian.

Other material examined

Eight speeimens: three speeimens (PMU 26835-26837), Osmundberget, Dalama; four speeimens (PMU

26838- 26841), Kallholn, Dalama; all from the Boda Limestone, Boda Core Member, late Katian.

Decription

The leetotype is a fragment of a very slightly eurved phragmoeone, 42 mm long, with a diameter that

inereases from 8 to 14 mm (angle of expansion 8.1°). It is ornamented with fine longitudinal raised

striae.

Speeimen PMU 26835 is a nearly straight portion of phragmoeone 43 mm long, inereasing in diameter

from 10 to 17 mm (angle of expansion 9.2°) (Fig. 23B) and a eireular eoneh eross seetion. The siphunele

is nearly eentral, 5.5 mm from the eoneh margin at a eorresponding eoneh diameter of 12.5 mm (SPR

0.44). The ehamber height is 3 mm at a diameter of 14.5 (0.21 of eoneh diameter). The diameter of the

septal perforation is 1 mm at a eoneh diameter of 12.5 mm (0.08 of eoneh diameter). The speeimen is

ornamented with fine raised lirae, ea. five per millimeter, and very faint, irregularly spaeed growth lines

ea. 1 mm apart (Fig. 171). Approximately 34 ea. 0.7 mm wide dark bands run longitudinally around the

entire eireumferenee (Fig. 28B).

In another speeimen (PMU 26836) the siphunele is more eeeentrieally positioned. At a eoneh diameter

of 21 mm, the siphunele is positioned 8 mm from eoneh margin (SPR 0.38).

The angle of expansion of the six available speeimens varies between 5.7 and 9.9°, with no size trend.

The ehamber height varies between 0.2 and 0.3 of the eorresponding eoneh height.

Remarks

The adult size of this speeies must be elearly more than 20 mm. The largest speeimen (PMU 26836) in

the eolleetion is a fragment of a phragmoeone with a diameter of 21 mm and the septal spaeing shows

no signs of septal erowding. The longitudinal ornamentation is erossed only by faint, irregularly spaeed

growth lines. A total of 34 longitudinal eolor bands are preserved around the entire eireumferenee of

the speeimen PMU 26835. This oeeurrenee of longitudinal eolor bands is known from other speeies of

Isorthoceras (see Kroger et al. 2009; Fig. 28), but their signifieanee for taxonomy is not known, beeause

of the rarity of this type of preservation.

Comparison

This speeies is unique amongst speeies eonsidered to belong to Isorthoceras in having exelusively

longitudinal lirae.

European Journal of Taxonomy 41: 1-110 (2013)

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Isorthoceras wahlenbergi Niko, 2008

Figs 4C, 26, 28C

Isorthoceras wahlenbergi Niko, 2008: 195, pi. 6, fig. 1.1-6.

Diagnosis

Isorthoceras with eireular eoneh eross seetion; smooth shell surfaee; weakly eurved growth axis with

siphunele slightly eeeentrie on eoneave side of eurvature; angle of expansion ea. 9°; mature body ehamber

with maximum diameter of 31 mm and two eonstrietions on body ehamber east; position of siphunele

shifting sightly toward the eenter during ontogeny; siphuneular segments pyriform to fusiform; with

weakly developed endosiphuneular deposits; septal neeks short, eyrtoehoanitie. (Adopted from Niko

2008.)

Type locality and horizon

Jutjam Quarry, Siljan district, Dalama, Sweden; Boda Limestone, Boda Core Member, late Katian,

Ordovician.

Material examined

Fifty-five specimens in the collections of the PMU: two specimens (PMU 26842,26843), Unskarsheden,

Dalama; 53 specimens (PMU 26844-26896), Kallholn, Dalama; all from Boda Limestone, late Katian.

Description

The species was described in detail by Niko (2008). Because I. wahlenbergi is one of the most common

cephalopods in the Boda Limestone. Fifty-three specimens are available for study in the collections

of the PMU. This material provides valuable additional data relating to the variability of some of the

characters. Measurements of the angle of expansion reveal an increase in the expansion rate up to

diameters of ca. 10 mm, when an a mean angle of ca. 10° is reached (Fig. 26). The nearly mature conch

expands more slowly and reaches its adult diameter at ca. 30 mm. The mean of all 47 measurements is

9.0° (L^ quantile 8.1°, 3*^^^ quantile 10.2°, n=47).

The chamber distance was measured in ten specimens. The chamber height is relatively small, with a

mean height 0.23 of the corresponding conch height (L^ quantile 0.22, 3"^^ quantile 0.26, n=10).

Remarks

Three fragments of I. wahlenbergi are preserved with a longitudinal color pattern. In specimen

PMU 26862 the shell is perfectly smooth; at a conch cross section of ca. 18-22 mm dark reddish,

irregularly spaced longitudinal bands occur with a distance of ca. 1-2 mm (ca. 100 would occur around

circumference. Fig. 28C). In PMU 26850, a portion of the phragmocone with a diameter increasing

from 17 to 13 mm, the smooth shell is partly ornamented with striae with a width of ca. 0.2 mm and

a distance of ca. 2 mm (ca. 50 would occur around circumference). The bands are irregularly carved

within the surface of the shell, which is otherwise smooth, and are interpreted as diagenetically altered

traces of a color pattern (Fig. 4C). A similar longitudinal color pattern is known from other species of

Isorthoceras, such as I. tenuitextum (Hall, 1847), I. romingeri (Foerste, 1932) (see Ruedemann 1919;

Foerste 1932: pi. 10; Kroger et al. 2009), I. heroyense comb. nov. and/, suave comb. nov. (see above.

KROGER B., Cephalopods of the Boda Limestone

Fig. 28). Beeause eolor pattern is relatively rarely preserved, its relevanee for speeies differentiation is

not known at the present.

Comparison

This speeies eonstitutes a large Isorthoceras. It is similar in size to I. dalecarliense Kroger et a/., 2011,

from whieh it differs in having a smaller angle of expansion of ea. 6° (Fig. 26). /. sociale from the

Maquoketa Formation, late Katian of the north-eentral USA is similar in dimension and general outline,

but differs in having a less expanded siphunele and a smaller adult size of only 25 mm.

Holland (1993) deseribed and figured a number of speeimens from the late Katian Kildare Limestone

of Ireland under the name ' Orthoceras" gregarium J. De C. Sowerb, 1839. These speeimens are similar

to I. wahlenbergi in general eoneh shape, in septal spaeing and siphunele position, as well as in having

a smooth surfaee, and probably must be synonymized with the latter. However, beeause the internal

eharaeters are not known from the Kildare Limestone eephalopods, a synonymization is impossible at

this point.

Stratigraphic and geographic range

Boda Limestone-Glisstjam Formation, late Katian-Himantian, Dalama, Sweden (see diseussion of

I. dale car lens e, above).

Suborder Lituitina Dzik, 1984

Family Sinoeeratidae Shimizu & Obata, 1935

Genus Tyrioceras Strand, 1934

Type species

Tyrioceras kjaerulfi Strand, 1934, Furuholmen, Asker Distriet, Norway, Grimsoy Formation, late Katian,

Late Ordovieian; by original designation.

Emended diagnosis

Large straight, eompressed to depressed eoneh eross seetion; ornamented with broad bands or narrower

raised transverse lines, whieh form broad and well marked, but not very deep ventral sinus with ventro¬

lateral and dorso-lateral salients, siphunele eeeentrie; septal neeks orthoehoanitie, relatively long,

siphuneular segments tubular.

Remarks

The external eharaeters of this genus where deseribed in detail by Strand (1934) and Frye (1982).

Originally the diagnosis of the genus was based only on the type speeies. In order to inelude T. warburgae

Frye, 1982, whieh is similar to the type in many aspeets, but differs in having a depressed, more rapidly

expanding eoneh, the diagnosis is emended.

The plaeement of Tyrioceras within the Lituitina, was formerly based on the eharaeteristieally eurved

ornamentation alone, and therefore was somewhat questionable. The details of the internal eharaeters,

now known from T. warburgae, support these earlier assumptions. The shape and extent of the

eameral deposits in T. warburgae are very similar to those of other lituitins. A syn-vivo dissolution

of the eonneeting ring, whieh is typieal of lituitins, is indieated by epiehoanitie deposits (Figs 29, 30).

Additionally, voluminous epi-, hyposeptal and mural deposits, and relatively long septal neeks are very

eharaeteristie for Lituitina. The assignment within the family of Sinoeeratidae is after Dzik (1984).

European Journal of Taxonomy 41: 1-110 (2013)

Tyrioceras cf. kjaerulfi Strand, 1934

Figs 8A, lOB, 29A, C, 30

Tyrioceras kjaerulfi Strand, 1934: 50, pi. 6.

Tyrioceras kjerulfi -Dzik 1984: 133, 138, text-fig. 55.5.

Diagnosis

Tyrioceras with angle of expansion of 11°; eompressed eoneh eross seetion; ornamented with marked

sinuous transverse growth lines that form ventral, lateral, and dorsal sinuses, and relatively deep

ventrolateral and dorsolateral salients. (Adopted from Strand 1934.)

Type locality and horizon

Furuholmen, Asker Distriet, Norway, Grimsoy Formation (questionable), late Katian, Late Ordovieian.

Material

One speeimen from Kallholn, PMU 26897, Siljan distriet, Dalama, Sweden; Boda Limestone, Boda

Core Member, late Katian, Ordovieian.

Description

Speeimen PMU 26897 is a portion of a phragmoeone 56 mm long with eoneh height and width

inereasing from 27 to 41 mm and 25 to 34 mm, respeetively. The angles of expansion are 14° and ea.

9°, respeetively, whereas the width/height ratio deereases from 0.93 apieally to 0.83 adorally (Figs 8A,

lOB). The relative ehamber height is 0.4, and the septal eonvexity is 0.25 of the eorresponding eoneh

height. The siphunele is subeentrally positioned with a diameter of ea. 0.13 of the eoneh eross seetion.

The eonneeting ring is not preserved, but the septal neeks are orthoehoanitie and relatively long with

ea. 0.45 of the ehamber height (Fig. 29 A, C). Heavy epi-, hyposeptal and mural deposits are developed.

Adapieally, the deposits eover the apieal septal neeks, forming epiehoanitie deposits (Fig. 30).

The eoneh surfaee is ornamented with transverse lirae, ea. 4-5 in a distanee of 1 mm. The spaeing of the

lirae varies periodieally, forming bands with widths of ea. 4 mm. The lirae form a shallow sinus on the

prosiphuneular, and a more pronouneed sinus on the antisiphuneular side of the eoneh.

Remarks

This speeies is based on a single, probably mature body ehamber fragment only. Nothing is known

about the ontogenetie and intraspeeifie variability of eharaeters sueh as angle of expansion, eoneh eross

seetion or ornamentation. The speeimen PMU 26897, deseribed above, is similar to Tyrioceras kjaerulfi

with respeet to the eompressed eoneh eross seetion and the irregularly spaeed transverse ornamentation.

However, the type of the speeies differs in having a eomparatively low angle of expansion (11°) and a

lower width/height ratio (0.79). The speeimens are provisionally interpreted as eonspeeifie.

Stratigraphic and geographic range

Grimsoy Formation (questionable), Asker Distriet, Norway; Boda Limestone, Dalama, Sweden, all late

Katian, Late Ordovieian.

Tyrioceras warhurgae Frye, 1982

Fig. 29B

Tyrioceras warburgae Frye, 1982: 1282, pi. 2, figs 5-7, text-fig.5.

KROGER B., Cephalopods of the Boda Limestone

Emended diagnosis

Tyrioceras with angle of expansion of 12-15°, with slightly depressed to slightly eompressed eoneh

eross seetion; ornamented with marked sinuous transverse growth lines that form ventral, lateral and

dorsal sinuses, and relatively deep ventrolateral and dorsolateral salients.

Type locality and horizon

Kallholn, Siljan distriet, Dalama, Sweden; Boda Limestone, late Katian, Ordovieian.

Material examined

Eleven speeimens in total: three speeimens (PMU 26898-26900), the holotype (PMU 24747) and five

paratypes (PMU 24748-24752), all from Kallholn; two speeimens from Unskarsheden (PMU 26901,

26902), Siljan distriet, Dalama, Sweden; Boda Limestone, latest Katian, Ordovieian.

Fig. 29. Polished median seetions of Tyrioceras Strand, 1934, Boda Limestone. A. Tyrioceras ef kjaerulfi

Strand, 1934, PMU 26897, Kallholn, detail of septal neek with massive endoeameral and epiehoanitie

deposits and long orthoehoanitie septal neeks. B. Tyrioceras warburgae Frye, 1982, PMU 26900,

Kallholn, detail of septal neek with epiehoanitie deposits. C. Same speeimen as in A, total fragment.

Seale bars: A-B = 5 mm; C = 10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Description

Frye (1982) described the ornamentation of this species in detail. Additional new details of the conch

shape and internal characters are described herein.

The holotype is a 67 mm long portion of phragmocone with a circular diameter at conch cross sections

increasing from 28 to 46 mm, with an angle of expansion of 15°. In two of the paratypes (PMU 24748,

24750), width/height ratios are 0.94 (at width 32 mm), 0.93 (at width 25 mm) and 0.94 (at width 75

mm), respectively.

Specimen PMU 26900 is a 65 mm long portion of a phragmocone with a conch height increasing from

34 to 47 mm (angle of expansion 11.3°). The conch cross section is slightly elliptically depressed, with

Fig. 30. Reconstruction of median section of Tyrioceras cf kjaerulfi Strand, 1934, PMU 26897, Boda

Limestone, Kallholn. Black = outer shell and septa; grey = cameral deposits.

KROGER B., Cephalopods of the Boda Limestone

a width/height ratio of 1.10. The sutures are direetly transverse, with a distanee between two septa equal

to ea. 0.4 of the eoneh height. The siphunele is slightly eeeentrie, with a SPR of 0.43 and a diameter of

0.17 of the eoneh eross seetion. The eonneeting ring is not preserved. The septal neeks are 6 mm long

and orthoehoanitie to suborthoehoanitie. On the prosiphuneular side, the ehambers are filled with heavy

epi-, and hyposeptal and mural deposits, whieh are partially fused. The hyposeptal deposits eover the

entire adapieal/extemal surfaee of the septal neek (Fig. 29B).

Remarks

Frye (1982) did not inelude the shape of the eross seetion in the original diagnosis of this speeies.

The eoneh eross seetion of the holotype is eireular. Additionally, there are speeimens with slightly

eompressed to slightly depressed eoneh eross seetion, whieh are identieal to the type in all other features.

The relatively low number of speeimens in the eolleetion does not allow for a proper evaluation of

this eharaeter for elassifieation purposes. Here, the variability in eoneh eross seetion is interpreted as

intraspeeifie and the speeies diagnosis is emended aeeordingly.

Comparison

Tyrioceras kiaerulfi differs from T. warburgae in having a eompressed eoneh eross seetion for its known

length and generally in having a lower angle of expansion.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Order Tarphyeerida Flower in Flower & Kummel, 1950

Family Diseoeeratidae Dzik, 1984

Genus Barrande, 1867

Type species

Clymenia antiquissima Eiehwald, 1842, Kardla, Hiiumaa Island, Estonia, presumably Vormsi/Pirgu

Regional Stage (“Lyekholm stage” of Teiehert 1930); by seeondary designation (Sehroder 1891).

Diagnosis

Gradually expanded tarphyeerids with smooth to strongly annulated eoneh; impression zone slightly

developed; subquadrate eoneh eross seetion; siphunele eentral in initial half-volution, gradually shifting

toward dorsal eoneh margin during later growth stages; thiek eonneeting rings. (Adopted from Furnish

& Glenister 1964b.)

Remarks

The genus Schroederoceras Hyatt, 1894 was regarded as synonymous with Discoceras Barrande,

1867 by Sweet (1958) and Furnish & Glenister (1964b). In the opinion of these authors, Discoceras

ineluded strongly annulated forms sueh as the type of Discoceras, Clymenia antiquissima Eiehwald,

1842, as well as smooth eonehs sueh as Lituites angulatus Saemann, 1852, the type of Schroederoceras.

Beeause several speeies show transitional morphologies from weakly ornamented to strongly annulate,

Schroederoceras and Discoceras are often diffieult to distinguish and the position advoeated by Sweet

(1958), who diseussed this issue in detail, is followed herein. Stumbur (1962) distinguished groups

of diseoeeratids by their eoneh eross seetion and ereeted new generie names. However, Dzik (1984)

already pointed out that the variation between the different shapes is eontinuous and sometimes ehanges

wit hin single speeimens. Based on the known variability of the material from the Boda Limestone, it is

impossible to distinguish different genera by eoneh eross seetion alone.

European Journal of Taxonomy 41: 1-110 (2013)

Discoceras antiquissimum (Eichwald, 1842)

Fig. 3 IB

Clymenia antiquissimaEiQ\mdX&, 1842: 33, pl. 3, figs 16, 17.

Lituites trapezoidalis Lossen, 1860: 25, pl. 1, fig. 2.

Clymenia antiquissima-Eioh^Ndld 1840: 15 {nomen nudum).

Lituites (Trocholites) antiquissimus - Schmidt 1861: 62, pl. 6, fig. 2a-g.

Lituites antiquissimus - Roemer 1861: 62, pl. 6, fig. 2f-g {non pl. 6, figs 2a-e = Discoceras roemeri

Strand, 1934, see below). — Karsten 1869: 53, pl.l9, fig. 7a-e. — Roemer 1885: 68, pl. 4, fig. 12.

Discoceras antiquissimum -ToqysXq 1925: 17, 58, pl. 18, fig. 1. — Strand 1934: 32, pl. 2, figs 4, 11, pl.

4, figs 2, 3, pl. 13, fig. 9. — Thorslund 1936: pl. 2, fig. 11. — Balashov 1953: 265, pl. 12, fig. la, b. —

Sweet 1958: 99, text-fig. 13q. — Neben & Krueger 1973: pl. 77, figs 24, 25. — Dzik 1984: 42, text-figs

9e-d, 12.39, pl.7, fig. 1.

Discoceras antiquissima - Hueke & Voigt 1967: 58, pl. 15, fig. 1.

Diagnosis

Discoceras with adult sizes more than 130 mm, WER of ea. 1.9 deereasing with inereasing eoneh size;

whorl eross seetion slightly depressed with WWl 1.2-1.5 beeoming less depressed in maturity, broadly

reniform in juvenile stages, rounded trapezoidal with venter wider than dorsum in later groth stages; free

mature body ehamber with eonstrietion near aperture; ornamented with prominent ribs, one to two ribs

per distanee between two septa; siphunele elose to dorsal eoneh margin, ea. 0.15-0.17 of whorl height,

septal neeks orthoehoanitie. (Adopted from Strand 1934.)

Type locality and horizon

Kardla, Hiiumaa Island, Estonia, presumably Vormsi/Pirgu Regional Stage (“Eyekholm stage” of

Teiehert 1930).

Material

Two speeimens, PMU 24739 and NRM-PZ Mo 8745, Kallholn, late Katian, Fate Ordovieian.

Description

This speeies was described in detail by Strand (1934). The specimen from the Boda Eimestone is

documented in order to add detail regarding the morphological variability of the species. The specimen

with a maximum conch diameter of 92 mm is a fragment with three whorls, lacking the free part

representing the mature stage. The maximum whorl height is ea. 22 mm and the maximum width 25 mm

(WWl 1.14), the whorl expands with a WER of 1.89. The conch is prominently annulated, with ea. 30

sharply crested ribs per 360° revolution. The ribs slope slightly adapically toward the venter and form an

angular v-shaped sinus on the venter. In addition to the conch annulation, the shell is ornamented with

fine, irregularly spaced, transverse growth lines parallel to the annulations.

Remarks

It is very probable that the specimen NRM-PZ Mo 8745 is that referred to by Strand (1934:36) from the Boda

Eimestone.

Comparison

This species, with its prominent juvenile to adult annulation, is unique within Discoceras.

KROGER B., Cephalopods of the Boda Limestone

Stratigraphic and geographic range

Bonsnes Formation, Ringerike district, “Gastropod Limestone”, Oslo-Asker, and Skien-Langesund

district, Norway (Strand 1934); erratic limestone boulders from northern Germany (Hucke & Voigt 1967),

and erratic limestone boulders from Vormsi/Pirgu Regional Stage (“Lyckholm stage”), Zawidowice,

Poland (Dzik 1984); Vormsi/Pirgu Regional Stage (“Lyckholm stage”), Estonia (Teichert 1930; Balasov

1953); Boda Limestone, Dalama, Sweden; all late Katian.

Discoceras roemeri Strand, 1934

Figs 31 A, 32, 33

Discoceras roemeri Strand, 1934: 38, 42-43, pi. 2, figs 6a-b, 7, pi. 5, figs 1, 2.

Schroederoceras balaschovi Stumbur, 1956: 181, pi. 1, figs 5, 6.

Lituites antiquissimus - Roemer 1861: 62, pi. 6, fig. 2a-e (non Discoceras antiquissimum (Eichwald,

1840)).

Discoceras angulatum -Mutyei 1957: text-fig. 12, pi. 8.

Discoceras roemeri - Sweet 1958: 99, 102, text-fig. 13p. — Dzik 1984: 41, 44, text-figs 10, 12.43, pi.

6, figs 5, 6.

Schroederoceras roemeri - Stumbur 1962: 136, text-fig. 2.4.

Rectanguloceras balaschovi - Stumbur 1962: 142, text-fig. 2.9.

Rectanguloceras {Discoceras) cf -Neben & Krueger 1973: pi. 65, figs 1, 2.

Diagnosis

Discoceras with large adult sizes of up to 150 mm, WER of 1.9-2.5, decreasing with increasing conch

size; whorl cross section slightly depressed with WWl 1.1-1.3, rounded subquadratic with venter

not wider than dorsum; body chamber nearly 180° long, free in mature growth stages and becoming

Fig. 31. Discoceratids of the Boda Limestone of Kallholn. A. Discoceras roemeri Strand, 1934, PMU

26903. B. Discoceras antiquissimum (Eichwald, 1842), NRM-PZ Mo 8745. Scale bar =10 mm for both

figures.

European Journal of Taxonomy 41: 1-110 (2013)

markedly higher during matures stages; ornamented with irregularly spaeed eostae and shallow ribs.

(Adopted from Strand 1934.)

Type locality and horizon

Frognoya, Tyrifjorden, Norway, Sorbakken Formation (Stage 4eh), late Katian, Ordovieian.

Material

Four speeimens (PMU 26903-26906), Kallholn; one speeimen (PMU 26907), Skalberget, Dalama,

Boda Limestone; one speeimen (PMU 26908), Amtjam, Dalama, Johnstorp Formation; all late Katian,

Late Ordovieian.

Fig. 32. Median eross seetions of Discoceras roemeri Strand, 1934, Boda Limestone, Kallholn. A. PMU

26903. B. PMU 26904. Seale bar =10 mm for both figures.

KROGER B., Cephalopods of the Boda Limestone

Description

This speeies was deseribed in detail by Strand (1934). The speeimens from the Boda Limestone

provide additional data regarding the ornamentation and the variability of the general eoneh shape. In

speeimen PMU 26903 the eoneh surfaee is well preserved (Fig. 31 A). The maximum diameter of this

speeimen is 72 mm with a maximum whorl height of 24 mm and width of 29 mm (WWI 1.21); the

WER of the speeimen is 2.16. The whorl eross seetion is subquadratie with a ea. 12 mm wide, slightly

rounded flattened venter, rounded umbilieal shoulders and a shallow impression zone. The speeimen

is ornamented with ea. 17 shallow, slightly irregularly marginally spaeed ribs on the outer whorl. The

ribs oeeur only on the umbilieal shoulders, not on the venter, whieh is almost flat. Narrowly spaeed,

pronouneed growth lines or eostae run parallel to the ribs and form a pronouneed u-shaped hyponomie

sinus.

The whorl expansion rate varies eomparatively strongly amongst the flve speeimens from the Boda

Limestone, with a maximum of 2.56 in speeimen PMU 26904 (Fig. 32B), a speeimen whieh agrees in

all features with other speeimens assigned to D. roemeri.

Remarks

Strand (1934: 46) deseribed some variation in his speeimen of D. roemeri. Within this

material, the type, whieh is from the Sorbakken Formation, differs Ifom younger speeimens of the

“Gastropod Limestone” in having a narrower venter. The Boda Limestone speeimens are most similar

to the speeimen of the Gastropod Limestone and to the speeimen flgured by Roemer (1861: pi. 6, flg 2a).

This is also apparent in the diagrammatie representation of the whorl expansion in Fig. 33, where the

variation of the speeimens from the Boda Limestone is eloser to the variation of the speeimen flgured

by Roemer (1861).

Comparison

Several speeies of Discoceras, deseribed from the Gastropod Limestone of the Oslo area (Strand 1934),

are very similar to the speeimens assigned to D. roemeri herein. Generally, these speeies differ in having

a lower expansion rate of ea. 1.8-1.9. Among them, D. angulatum is most similar to D. roemeri with

respeet to the eoneh eross seetion. D. angulatum also has similarly rounded umbilieal shoulders, but in

40 50 60 70 80 90 100 1.8 2.0 2.2 2.4 2.6 2.8 40 50 60 70 80 90 100

conch diameter in mm relative whorl width conch diameter in mm

Fig. 33. Morphologieal variation in Discoceras roemeri Strand, 1934. Blaek dots = speeimens of the

Boda Limestone. Blaek dot with grey margin = Rectanguloceras balaschovi Stumbur, 1962. Grey dots

= Lituites antiquissimus of Roemer (1861: pi. 6, flgs 2a-e). Grey dot with blaek margin = Discoceras

roemeri of Dzik (1984: pi. 6, flgs 5,6). White dot with blaek eirele = Discoceras roemeri of Strand

(1934: pi. 5, flg. 1). WER = whorl expansion rate.

European Journal of Taxonomy 41: 1-110 (2013)

contrast to D. roemeri the width of the ventral side of the whorl is always less than that of the dorsal

side, and appears to be flatter.

The diagrammatie representation of the morphologieal variation of different speeimens assigned to

D. roemeri and the eomparison of eross seetions reveal that Schroederoceras balaschovi Stumbur, 1956

from the Pirgu Stage of Estonia mdDiscoceras vasegaardense Rasmussen & Surlyk, 2012 from the late

Katian Lindegard Formation of Bornholm, Denmark are well within the range of variation ofD. roemeri

and must be synonymized with the latter (Fig. 33). However, beeause details of the eross seetion of

D. vasegaardense are not known and the ribbing in this speeies appears to be stronger than in speeimens

assigned to D. roemeri it eannot be synonymised with the latter. On the other hand, Schroederoceras

balaschovi is interpreted as a junior synonym of D. roemeri, herein.

Stratigraphic and geographic range

Venstop and Sorbakken formations, Ringerike district, and Venstop and Grimsoy formations, Oslo-Asker

district, upper Heroya Formation (“Gastropod Fimestone”), Skien-Fangesund district, Norway (Strand

1934); erratic limestone boulders from Vormsi/Pirgu Regional Stage (“Fyckholm stage”), Zawidowice,

Poland (Dzik 1984); Vormsi/Pirgu Regional Stage (“Fyckholm stage”), Estonia (Teichert 1930; Stumbur

1956, 1962); Boda Fimestone, Dalama, Sweden; all late Katian.

Order Barrandeocerida Flower in Flower & Kummel, 1950

Remarks

The order Barrandeocerida was not accepted by Dzik (1984: 46), who placed the genus Barrandeoceras

Hyatt, 1884 within the Tarphyceratidae, or by Flower (1984: 1377), who placed the family

Barrandeoceratidae within the Tarphycerida. However, Barrandeoceras and similar forms, which

were assigned to the Barrandeocerida by Flower & Kummel (1950) and Sweet (1964a) are clearly

distinguished from Tarphycerida in having a thin-walled orthocerid-like siphuncle with achoanitic to

cyrtochoanitic septal necks. The differences between the connecting ring structure and morphology in

tarphycerids and barrandeocerids were examined and discussed by Mutvei & Dunca (2011), renewing

earlier hypotheses (see Flower 1984) of an orthocerid ancestry for the Barrandeocerida (see discussion

below).

Family Uranoceratidae Hyatt in Zittel, 1900

Genus Siljanoceras gen. nov.

um:lsid:zoobank.org:act:71F25FD0-6E8D-4753-9CA2-B0137EC6D22B

Type species

Siljanoceras varians gen. et sp. nov., Kallholn, Dalama, Sweden, Boda Fimestone, Boda Core Member,

late Katian, Ordovician.

Diagnosis

Rapidly expanding curved conchs with circular to slightly depressed conch cross section; mature body

chamber with clearly depressed cross section; nearly straight in late growth stages, more strongly curved

in early growth stages, continuously expanding in height, slightly bulbous in width, with decreasing width

near aperture; cross section more rounded on dorsal side and slightly flattened on venter; ornamented

with flne longitudinal striae and irregularly spaced faint growth lines, which form shallow sinus on

venter; siphuncle eccentrically positioned at convex side of conch curvature; siphuncular segments

barrel-shaped, widely expanded; septal necks achoanitic.

KROGER B., Cephalopods of the Boda Limestone

Etymology

From Lake Siljan, Dalama, Sweden.

Remarks

The deereasing eoneh eurvature during maturity, the position and shape of the siphunele, the

ventromyarian periphraet (Fig. 34) and the longitudinal ornamentation are eharaeters that are typieal of

the Uranoeeratidae and justify an assignment of this new genus within this family.

An apieal fragment, PMU 26918, questionably is from a Siljanoceras gen. nov. (Fig. 35E-F). It ean be

deseribed as following: The tip of the fragment is eup-shaped, at ea. 2 mm from the tip the eoneh height

is 4.5 mm, the width 4.3 mm. The eoneh surfaee is ornamented with a shallow rounded annulation (ea.

3 annuli per millimetre) and faint longitudinal striae. The annuli have a shallow hyponomie sinus on

the eoneave side of the shell eurvature. The eoneh is very slightly eurved and expands with an angle of

ea. 33° and is nearly eireular in eoneh eross seetion at a eoneh diameter of ea. 9 mm. The siphunele is

positioned elose to the eoneh margin and is ea. 0.08 of the eoneh diameter.

Comparison

Among other openly eoiled Barrandeoeerida, this genus is unique in its eombination of a siphunele that

lies toward the eoneh wall on the eonvex side of the eoneh eurvature and the eoneh eross seetion being

more rounded on the dorsum (eoneave side of eoneh eurvature). In its non-annulated, longitudinally

striated shell surfaee, it is most similar to Uranoceras Hyatt, 1884, but differs from this genus in being

more openly eoiled and more rapidly expanding.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Species included

Siljanoceras varians sp. nov., Siljanoceras sp. A.

Siljanoceras varians sp. nov.

um:lsid:zoobank.org:aet:E4162038-CBQ2-4BDC-B8B3-EDE3417D298Q

Figs 34, 35A-D, G-I, 36C-D, 37, 38

Diagnosis

Siljanoceras gen. nov. with angle of expansion of ea. 25°, with eireular to slightly depressed eoneh eross

seetion; siphunele eeeentrieally positioned with distanee of ea. 0.3 of eorresponding eoneh diameter

from eoneh margin at eonvex side of eoneh eurvature; siphuneular segments barrel-shaped, widely

expanded within ehambers with diameters of 0.16-0.2 of eorresponding eoneh eross seetion; septal

neeks aehoanitie.

Etymology

Refers to the relatively high morphologieal variability, Latin variabilis, of this speeies.

Type material

Holotype

PMU 26909.

European Journal of Taxonomy 41: 1-110 (2013)

Paratypes

Seven paratypes (PMU 26910-26916), Kallholn, Dalama, Sweden, Boda Limestone, Boda Core

Member, late Katian, Ordovieian.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is a fragment of a slightly eurved mature body ehamber (Figs 34,35A-B, G). The elliptieally

eompressed body ehamber has an apieal height of 58 mm and width of 67 mm (width height ratio =

1.16), an adoral height of 92 mm against a width of 105 mm. The eoneh margin is flattened at the eonvex

side of the eoneh eurvature and more rounded at the eoneave side. In lateral view the eoneh eontinuously

expands with an angle of 23° and its width expansion deereases over the entire length of the speeimen

with an overall angle for the preserved portion of expansion of 25°. In the adoral 10 mm of the fragment

the eoneh width deereases slightly, giving the body ehamber a slightly bulbous shape.

The siphunele is eeeentrieally positioned with diameter of the septal perforation of 3 mm (0.05 of

eorresponding eoneh height). The siphunele is situated at a distanee of ea. 18 mm from the eoneh margin

at the eonvex side of the eoneh eurvature, where the eoneh height is 58 mm (SPR 0.31).

The shell surfaee is nearly smooth. Fine, irregularly spaeed, rounded growth lines or striae form a very

shallow salient on the lateral sides and faint traees of longitudinal striae are preserved. The suture of the

last ehamber is transverse. The septum is shallow and eap-shaped.

At the base of the body ehamber the periphraet is preserved as an impression on the internal mould (Fig.

34). The periphraetie imprint forms a narrow ea. 5 mm wide band with an irregular margin on the lateral

and dorsal (antisiphuneular) sides. Ventrally, a pair of adjaeent impressions, eaeh ea. 13 mm wide, oeeur.

Fig. 34. Musele attaehment sears Ifom ventromyarian periphraet in Siljanoceras varians sp. nov.,

PMU 26909, holotype, Kallholn. Seale bar =10 mm.

KROGER B., Cephalopods of the Boda Limestone

The fine, longitudinally and transversely striated ornamentation is best preserved in speeimen PMU

26913 (Fig. 37). In this speeimen the longitudinal elements are preserved as fine, raised striae with a

distanee of ea. 0.2 mm at a eoneh height of ea. 30 mm.

The ehamber height is ea. 0.16 of the eorresponding eoneh height (based on measurements on speeimens

PMU 26913 and 26915). The sutures are straight and direetly transverse.

Details of the internal morphology are preserved in speeimen PMU 26915, whieh is a fragment eonsisting

of five ehambers and part of a body ehamber, with eoneh height inereasing from 19 to 35 mm (Fig. 36C).

The septa are direetly transverse and ea. 0.17 of the eoneh height in distanee. The septal perforation

is eeeentrieally positioned at a distanee of 5 mm apieally, and 7 mm adorally (SPR ea. 0.25-0.26).

The septal neeks are aehoanitie. The siphunelular segments are barrel-shaped, widely expanded. In the

adapieal-most ehamber the siphunele is signifieantly less expanded (0.16 of eorresponding eoneh eross

seetion) than in the adoralmost ehamber (relative siphuneular diameter 0.2).

Fig. 35. Siljanoceras gen. nov., Kallholn, Boda Limestone. A-D. Siljanoceras varians sp. nov. A. PMU

26909, holotype, mature body ehamber, view from prosiphuneular side. B. Same speeimen, lateral view.

C. PMU 26913, lateral view. D. Same speeimen, adapieal view. E-F. Apieal fragment of Siljanoceras?

sp., PMU 26918. E. Lateral view. E. Adapieal view. G-I. Siljanoceras varians sp. nov. G. Same speeimen

as in A-B, adapieal view. H. PMU 26914, lateral view. I. Same speeimen view from prosiphuneular side.

Seale bars: A-D, G-I =10 mm; E-F = 2 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Remarks

Some of the speeimens assigned to this speeies were slightly emshed during deposition and as a

eonsequenee show aberrant eoneh eross seetions. Therefore, the variability in eoneh eross seetion shape

and angle of expansion is diffieult to evaluate. Generally, a trend of inereasing eompression of the eoneh

eross seetion ean be aseertained (Fig. 35). Based on the limited material available it seems reasonable

Fig. 36. Polished median seetions of Siljanoceras gen. nov., Boda Limestone. A. Detail of siphuneular

segment of Siljanoceras sp. A, PMU 26917, Kallholn. B. Same speeimen, total view. C. Siljanoceras

varians sp. nov., PMU 26915, Kallholn; detail of apieal-most siphuneular segment, seetion not perfeetly

in median plane, with adapieal septal perforation not preserved. D. Same speeimen, total view. Seale

bars: A, C = 1 mm; B, D = 5 mm.

KROGER B., Cephalopods of the Boda Limestone

to assume that the eoneh eross seetion varies from nearly eireular to slightly depressed (Fig. 38) and the

angle of expansion varies aeross the sample between 23 and 31° (Fig. 38).

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Fig. 37. Detail of ornamentation of Siljanocer as varians sp. nov., PMU 26913, Kallholn, Boda Limestone;

position of apex down. Seale bar =10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Siljanoceras sp. A.

Figs 36A-B, 38

Material

One specimen (PMU 26917), Kallholn, Siljan District, Sweden; Boda Limestone, Boda Core Member,

late Katian.

Description

Specimen PMU 26917 is a mildly deformed portion of a slightly curved phragmocone, 23 mm long with

a conch height of ca. 22^0 mm and a conch width of ca. 20^0 mm (angle of expansion ca. 38°) (Fig.

3 6 A, B). The original shape of the conch cross section is difficult to evaluate, but was probably slightly

depressed. The conch surface is poorly preserved and no signs of ornamentation are visible. The sutures

are nearly transverse and have a distance of ca. 0.17 of the corresponding conch cross section.

The position of the septal perforation is eccentric (SPR 0.4). The siphuncular segments are barrel-shaped

and widely expanded with maximum diameter of ca. 0.18 of the corresponding conch cross section. The

septal necks are achoanitic.

Remarks

This fragmentarily preserved specimen differs from Siljanoceras varians gen. et sp. nov. in having a

less curved, more expanded conch with a less eccentric siphuncle, that appears slightly more expanded

within the shell. The general conch form is similar to that of Siljanoceras gen. nov. and it is therefore

assigned to this genus. However, a species determination is impossible based on this imperfectly known

specimen.

Genus Warburgoceras gen. nov.

um:lsid:zoobank.org:act:7BD9C0A9-AFD0-4AD8-B910-BFC3E32AD603

Type species

Cyrtoceras longitudinale Angelin in Angelin & Lindstrom, 1880, Kallholn, Dalama, Sweden, Boda

Limestone, Boda Core Member, late Katian, Ordovician; by montotypy.

20 30 40 50 60 70 80 90

conch diameter in mm

■(D

20 30 40 50 60 70 80 90

conch diameter in mm

Fig. 38. Morphological variation of Siljanoceras gen. nov. Black dots = Siljanoceras varians sp. nov.;

grey dot = Siljanoceras sp. A.

KROGER B., Cephalopods of the Boda Limestone

Diagnosis

Continuously expanding gyroeones with eireular, slightly eompressed or slightly depressed eross

seetion; angle of expansion in premature stages ea. 13°, deereasing during growth; ornamented with

fine, irregularly spaeed growth lines that form broad, shallow sinus on eonvex side of eoneh and with

fine irregularly spaeed longitudinal striae; mature body ehamber with only weak terminal eonstrietion;

sutures straight and nearly direetly transverse, with shallow lobe on prosiphuneular side of eoneh; ea.

4-5 ehambers per distanee similar to eorresponding eoneh height; siphunele eeeentrieally positioned,

with SPR of ea. 0.1 at eonvex side of eoneh eurvature; siphuneular segments slightly expanded within

ehamber, siphunele diameter ea. 0.09 of eorresponding eoneh eross seetion; eonneeting ring thin; septal

neeks short, loxoehonoanitie-suborthoehoanitie.

Etymology

In honor of Elsa Warburg (1886-1953), a Swedish paleontologist who published her doetoral thesis on

the trilobites of the Boda Limestone (Warburg 1925) and eolleeted most of the eephalopods of the Boda

Limestone during the first deeades of the 20^*^ Century.

Remarks

The position and shape of the siphunele and the longitudinal ornamentation are eharaeters that are

typieal of the Uranoeeratidae and justify an assignment of this new genus within this family.

Comparison

Deckeroceras Foerste, 1935 from the late Katian Femvale Formation of Oklahoma is most similar to

Warburgoceras gen. nov. in general eoneh shape, but the body ehamber is more infiated in the former,

the siphunele is more expanded and less eeeentrie, and the features of the external shell are not known.

It is possible that Warburgoceras gen. nov. is a subjeetive junior synonym of Deckeroceras. However,

sinee no details of the external shell are known from the latter and the types of both genera differ in some

details, Warburgoceras gen. nov. is ereeted herein.

Warburgoceras gen. nov. differs from Uranoceras Hyatt, 1884 in having a nearly eireular eoneh eross

seetion, non-lobate, direetly transverse sutures and in beeing more openly eurved.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Species included

Type speeies only.

Warburgoceras longitudinale (Angelin Angelin & Lindstrom, 1880) eomb. nov.

Figs 18F, 39C

Cyrtoceras longitudinale Angelin Angelin & Lindstrom, 1880: 11, pi. 16, fig. 5.

Uranoceras (?) longitudinale -Mutvei 1957: 245, text-figs 6e, 7b, 10, 11, 20, 21, pi. 4, fig. 3, pis 6, 7,

17, 18. — Dzik & Kom 1992: 84, 85, text-fig. 1.

Uranoceras longitudinale - Dzik 1984: 150, 154, text-fig. 59.2.

Diagnosis

Same as for genus by monotypy.

European Journal of Taxonomy 41: 1-110 (2013)

Type locality and horizon

Osmundsberget, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Material

Four speeimens, two from Kallholn (PMU 26919,26921), one from Osmundsberget (NRM Mo 154065)

and one from Unskarsheden (PMU 26920); Boda Limestone, late Katian, Dalama, Sweden.

Remarks

This speeies was extensively deseribed by Mutvei (1957). Additionally, the ventromyarian periphraet

was figured in three speeimens with the mature body ehamber preserved (Mutvei 1957: pi. 4.3, fig. 4; pis

6, 7). Two more speeimens with eomplete mature body ehambers are in the eolleetions of the NMR and

PMU. Both body ehambers are nearly identieal in maximum eoneh height (58 mm), whieh is reaehed at

the peristome. The body ehamber eontraets only very slightly elose to the peristome and has a length of

90-100 mm (NRM Mo 154065, PMU 26919) (height/length ratio of body ehamber ea. 0.6).

Comparison

Warburgoceras longitudinale eomb. nov. is very similar to Redpathoceras bullatum sp. nov. withrespeet

to ornamentation (both speeies have a similar distinetively longitudinally lirate surfaee; Fig. 18F), and

are identieal in angle of expansion, eoneh eurvature, eoneh eross seetion and mature size (Fig. 39C).

They differ, however, in two main aspeets: (1) the mature body ehamber of R. bullatum sp. nov. is

infiated, with a maximum height at the mid-length, whereas the body ehamber of W. longitudinale eomb.

nov. opens gradually, (2) the eoneh of R. bullatum sp. nov. displays deeply eoneave septa of truneation

at regular distanees. This similarity strongly suggests a elose phylogenetie relationship between the two

speeies, genera and higher taxa to whieh they belong (see diseussion above).

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Order Aseoeerida Kuhn, 1940

Family Aseoeeratidae Barrande, 1867

Genus Schuchertoceras Miller, 1932

Type species

Ascoceras anticostiensis Billings, 1866. Junction eliff, Antieosti Island, Canada. Probably the Ellis Bay

Formation, Himantian, Late Ordovieian; by original designation.

Diagnosis

Aseoeeratid eephalopods with basal non-aseoeeroid septum between septum of tmneation and the first

aseoeeroid septum in mature eoneh. (Adopted from Frye 1982.)

Schuchertoceras fryi sp. nov.

um:lsid:zoobank.org:aet:BAQ2C2EE-982A-483B-9QDF-46E5E5F8QFD4

Figs lOF, 39F

Schuchertoceras troedssoni -Trye 1982: 1280, pi. 1, fig. 3 (non pi. 1, figs 1, 2, 5).

KROGER B., Cephalopods of the Boda Limestone

Diagnosis

Schuchertoceras with gibbous mature eoneh with slightly depressed eross seetion, a basal septum and

one aseoeerid septum, a highly eonvex septum of truneation and a mature body ehamber height of ea.

40 mm.

Fig. 39. Aseoeerida and Uranoeeratidae of the Boda Limestone. A-B. Redpathoceras bullatum sp. nov.

A. PMU 26923, holotype, Kallholn; mature truneated body ehamber, lateral view. B. Same speeimen,

view from antispihuneular side. C. Warburgoceras longitudinale (Angelin in Angelin & Lindstrom,

1880) eomb. nov., NRM-PZ Mo 154065, Unskarsheden; mature body ehamber and part of phragmoeone

in lateral view. D-E. Probillingsites scandinavicum sp. nov., PMU 26922, holotype, Kallholn. D.

Mature truneated body ehamber, lateral view. E. Same speeimen, view from prosiphuneular side. E.

Schuchertoceras fryi sp. nov., PMU 24744, holotype, Kalllholn, lateral view. Seale bars: A-E =10 mm;

F = 10 mm.

European Journal of Taxonomy 41: 1-110 (2013)

Etymology

Refers to Mark W. Frye, who first deseribed some of the aseoeerids of the Boda Limestone (Frye 1982).

Holotype

PMU 24744.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The speeimen is a eomplete fragment of a mature eoneh. The outer shell is partially preserved and nearly

smooth with fine, irregularly spaeed growth lines. The total eoneh length is 65 mm and the maximum

height of 40 mm and width of 44 mm (ratio width/height 1.1) are reaehed at approximately mid-length

of the mature body ehamber (Fig. 39F). The length/height ratio of the mature eoneh is 0.61. The aperture

is depressed, elliptieal in eross seetion, with a height of 32 mm and a width of ea. 36 mm. The septum

of truneation is highly eonvex and dome-shaped, with a height of ea. 14 mm and oblique. The septal

perforation is elose to the eoneh margin (ea. 5 mm). The aseoeerid septum forms a short and pointed lobe

and a wide and shallow sinus and almost reaehes the aperture on the antisiphuneular side of the eoneh.

The prosiphuneular side is slightly fiattened in eross seetion (Fig. lOF).

Remarks

This speeimen was assigned to Schuchertoceras troedssoni Frye, 1982 by Frye (1982: 1280) and

deseribed as an “unusually gibbous, and nearly egg-like” speeimen. A reinvestigation of the speeimens

deseribed by Frye (1982) reveals that PMU d727 is not only signifieantly larger than the other speeimens

assigned to S. troedssoni, whieh have a mature length of 40-50 mm only, but differs in having a highly

eonvex septum of truneation. This is in strong eontrast to the type of S. troedssoni, whieh possesses a

relatively shallow and fiat septum of truneation and whieh is elearly less gibbous in general eoneh form.

These differenees are eonsidered to be signifieant here and justify the ereetion of a new speeies for this

speeimen.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Family Probillingsitidae Flower, 1941

Genus Probillingsites Foerste, 1928

Type species

Probillingsites welleri Foerste, 1928, Wiseonsin, USA; probably Galena Dolomite, early-mid Katian,

Ordovieian; by original designation.

Emended diagnosis

Cyrtoeones with tmneated eoneh; mature eoneh infiated, higher than long or height similar to length;

eoneh eross seetion eireular to depressed; mature sutures generally oblique and slightly sinuous or

sigmoid, but not laeunose; septal neeks in latest septa strongly reeumbent, eyrtoehoanitie, in earlier

septa suborthoeoanitie; siphuneular segments expanded.

KROGER B., Cephalopods of the Boda Limestone

Remarks

The morphology of Probillingsites scandinavicum sp. nov. indieates that the eoneept of Probillingsites

requires adjustment as it is transitional between Redpathoceras and typieal Probillingsites. In faet,

the distinetion between Redpathoceras and Probillingsites must be drawn relatively arbitrarily at the

tenuous border between a mature body ehamber eharaeterized as “strongly inflated” {Probillingsites)

or “inflated” {Redpathoceras), or between a mature truneated eoneh that is “obese” {Probillingsites)

or brevieonie {Redpathoceras). The ratio of the height/length of the mature eoneh may be used as a

quantitative measure to distinguish between the two genera. In Redpathoceras clarki Flower, 1963, the

type of Redpathoceras, this ratio is 0.48 and in R. magum sp. nov. and R. bullatum it is 0.46; in typieal

Probillingsites the height is greater than or equal to the length. In P. scandinavicum sp. nov. this ratio

is 0.52. Consequently, here Probillingsites is restrieted to Probillingsitidae with eoneh heights that are

greater than or equal to the mature eoneh length.

Probillingsites scandinavicum sp. nov.

um:lsid:zoobank.org:aet:42510E86-B2FE-40F7-8ED5-319BD939BDD4

Fig. 39D-E

Diagnosis

Probillingsites with a smooth mature eoneh with depressed eoneh eross seetion; eoneh margins in

longitudinal view eonvex on prosiphuneular side and eoneave on antisiphuneular side; maximum eoneh

height of ea. 55 mm at mid-length of body ehamber; septa of mature eoneh slightly oblique; sutures

nearly straight.

Etymology

Refers to the larger type area; this is only the seeond speeies of Probillingsites known from the region.

Holotype

PMU 26922.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The speeimen is a nearly eomplete fragment of a mature eoneh, with a length of ea. 105 mm. The height

of the septum of truneation is 39 mm and the apertural height is ea. 40 mm. The maximum height

of 55 mm of the eoneh is approximately at mid-length of the body ehamber, where the width is 59

mm (width/height ratio 1.07) (Fig. 39D, F). In eross-seetion the prosiphuneular side is more rounded,

the prosiphuneular side slightly flattened. The aperture is eonstrieted and depressed with an elliptieal

eross-seetion. The eoneh surfaee is poorly preserved but appears to be ornamented with line, irregularly

spaeed growth lines.

The phragmoeone is ea. 35 mm long and eonsists of four ehambers. The septa are simple eonvex and

slightly oblique, projeeting toward the aperture on the antisiphuneular side. The septum of truneation is

relatively shallow with a depth of ea. 6 mm.

Comparison

This speeies is unique amongst the known speeies of Probillingsites in having only simple straight septa

in the mature eoneh, a relatively long body ehamber and a shallow eonvex septum of truneation.

European Journal of Taxonomy 41: 1-110 (2013)

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Genus Redpathoceras Flower, 1963

Type species

Redpathoceras clarki Flower, 1963, northeast of Joliette, Quebee, Canada; Leray Limestone, early-mid

Katian, Ordovieian; by original designation.

Diagnosis

Gyroeones with eireular to depressed mature eoneh eross seetion; mature body ehamber inflated with

greatest diameter at approximate mid-length; broad shallow hyponomie sinus; septum of truneation

deeply rounded; suture of septa in mature speeimen slightly oblique, sloping in adoral direetion on

eoneave side of eoneh eurvature; siphunele eeeentrie, elose to eoneh margin at eonvex side of eoneh

eurvature. (Adopted from Flower 1963.)

Remarks

Redpathoceras was assigned to the Probillingsitidae by Flower (1963) beeause of its deeply rounded

septum of truneation and its inflated mature body ehamber. The type speeies, Redpathoceras clarki, is

eharaeterized by a mature shell with only two ehambers adoral of the terminal truneation; this is similar

to Probillingsites. Some speeimens of Redpathoceras from the Boda Limestone have mature truneated

shells with flve ehambers {Redpathoceras magnus sp. nov.); this is very similar to Montyoceras Flower,

1941, and supports Flower’s (1963) hypothesis of an aneestry of Billingsites and other aseoeerids from

a Montyoceras-WkQ form. (The truneated parts of premature Redpathoceras phragmoeones eonsist of ea.

seven to eight ehambers.)

On the other hand, the strongly eurved eoneh portions of Redpathoceras are very similar to some

uranoeeratids, sueh as Deckeroceras Foerste, 1935, Siljanoceras gen. nov. and Warburgoceras gen.

nov., from whieh it mainly differs in having a deeply eonvex septum of truneation. This suggests a

relationship of Uranoeeratidae with aseoeerids (see diseussion below).

The shape of the septal neeks and eonneeting ring of the speeies of Redpathoceras known from the

Boda Limestone are similar to those of Probillingsites (eompare with Furnish & Glenister 1964a: flg.

189.4; Fig. 40A-C). The eonneeting ring is slightly expanded in juvenile ehambers and nummoidal and

strongly expanded in the latest ehambers. The septal neeks are suborthoehoanitie in juvenile stages and

distally thiekened and aehoanitie in the latest stages.

Stratigraphic and geographic range

Leray Limestone, early-mid Katian, Quebee, Canada; Boda Limestone, late Katian, Dalama, Sweden.

Redpathoceras bullatum sp. nov.

um:lsid:zoobank.org:aet:B2601C0D-00FD-4084-B303-E0A0CB27E4A3

Figs lOG, 39A-B, 40, 41, 42

Diagnosis

Redpathoceras with eurved mature body ehamber, inflated in lateral view with maximum height of ea.

60 mm at mid-length of body ehamber; in longitudinal seetion mature body ehamber eoneh margin at

eoneave side of growth axis eoneave throughout total length; eoneh eross seetion eompressed to eireular

in earlier growth stages; premature eoneh expands at 15°; diameter of terminal septum of tmneation ea.

KROGER B., Cephalopods of the Boda Limestone

45 mm; ornamented with fine longitudinal striae and irregularly spaeed transverse growth lines, whieh

form a wide hyponomie sinus.

Etymology

From Latin bullatus, sausage, referring to the form of the mature eoneh of this speeies.

Type material

Holotype

PMU 26923.

Paratypes

Three paratypes (PMU 26924-26926), Kallholn, Dalama, Sweden, Boda Limestone, Boda Core

Member, late Katian.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is an ineomplete internal mould of a mature body ehamber with partly reerystallised shell

fragments attaehed (Figs lOG, 39A-B). The septum of tmneation and parts of the phragmoeone are not

preserved in the holotype. The base of the body ehamber is 51 mm high and 49 mm wide (height/width

ratio 1.04). The dimensions of the aperture are not preserved, but its total length is estimated at ea. 105

mm. The body ehamber reaehes its greatest height of 60 mm at mid-length. The eoneh margin at the

eoneave side of the eoneh eurvature is eurved throughout the total length of the body ehamber.

The shell surfaee is nearly smooth with irregularly spaeed growth lines, whieh form a broad shallow

sinus on the eonvex side of the eoneh eurvature. Traees of longitudinal striae are visible in parts of the

surfaee.

Fig. 40. Polished median seetion of Redpathoceras bullatum sp. nov., PMU 26926, Kallholn, Boda

Limestone. A. Complete truneated phragmoeone fragment. B. Adoral part with erowded septa and

expanded siphuneular segments. C. Adapieal part with wide septald distanee and elongated siphuneular

segments. Seale bars: A = 10 mm; B-C = 5 mm.

European Journal of Taxonomy 41: 1-110 (2013)

The siphuncular perforation measures 5 mm (ea. 0.1 of eoneh height) and is positioned ea. 7 mm from

the eoneh margin on the eonvex side of the eoneh eurvature. The shell is ea. 1 mm thiek at mid-length

of the body ehamber.

Speeimen PMU 26926 is a eomplete, tmneated portion of the phragmoeone with a length at growth

axis of ea. 40 mm and a eoneh height inereasing from 33 to 44 mm (angle of expansion 15.4°) (Figs

40, 41). The shell surfaee is well preserved and exhibits a fine longitudinal striation. The distanee of the

longitudinal striae varies between 0.5 and 1 mm. Another speeimen, representing the tmneated part of a

phragmoeone (NRM Mo 152774), is 60 mm long and inereases from 31 to 45 mm in height, and eonsists

of eight ehambers.

PMU 26926 (Fig. 40) eomprises seven ehambers with sueeessively deereasing depth and eonvexity in

the direetion of growth. The depth of the apieal-most ehamber is 8 mm, and its septa are deeply eonvex.

By eontrast, the adoral-most ehamber is only 4 mm deep, with only a very shallow, eonvex septa.

The septal perforation is positioned ea. 7 mm from the eoneh margin at the adoral-most septum. The

septal neeks are very unusual in being distally thiekened, with the eonneeting rings forming an adnate

attaehment in the three erowded adoral-most septa. The septal neeks assoeiated with the remaining septa

are suborthoehoanitie. The eonneeting ring is thin and expanded between the ehambers. The expansion

of the siphuneular segments is highest in the adoral-most ehambers.

Fig. 41. Redpathoceras bullatum sp. nov., PMU 26926, Kallholn, Boda Limestone. A. Polished median

seetion of detail of the septal neek and eonneeting ring. B. Reeonstruetion of A. C. Reeonstruetion of the

total tmneated fragment. Seale bar: A-B = 1 mm.

KROGER B., Cephalopods of the Boda Limestone

Comparison

This speeies of Redpathoceras differs from R. magnum sp. nov. in having a smaller mature eoneh of

maximum height of 60 mm (Fig. 42), and in being entirely eurved in lateral view on both the eonvex and

eoneave side of the eoneh eurvature. R. bullatum sp. nov. is larger than the type of the genus and has a

less eompressed eoneh eross seetion.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Redpathoceras depressum sp. nov.

um:lsid:zoobank.org:aet:C6767BCC-4FD2-4A7E-BE5C-F4738889A43E

Figs lOE, 18G, 42, 43D-F

Diagnosis

Redpathoceras with eurved mature body ehamber; inflated in lateral view with maximum height of ea.

55 mm at mid-length of body ehamber; mature body ehamber margin at eoneave side of eoneh eurvature

eoneave throughout total length; eoneh eross seetion depressed; premature eoneh expands with angle

of expansion less than 10°; diameter of terminal septum of truneation ea. 45 mm; ornamented with flne

longitudinal striae and irregularly spaeed transverse growth lines, whieh form a wide hyponomie sinus.

Etymology

Refers to the distinetively depressed eoneh eross seetion of this speeies.

35 40 45 50 55

conch diameter in mm

Fig. 42. Variation in angle of expansion in Redpathoceras Flower, 1963, Boda Limestone. R. magnum

sp. nov. (grey dots); R. bullatum sp. nov. (blaek dots); R. depressum sp. nov. (blaek eireles).

European Journal of Taxonomy 41: 1-110 (2013)

Type material

Holotype

PMU 26927.

Paratypes

Seven paratypes (PMU 26928-26934), Kallholn, Dalama, Sweden, Boda Limestone, late Katian.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is a nearly eomplete mature eoneh, 120 mm long. The eoneh is depressed with a height of

41 mm and width of 48 mm at the septum of tmneation (width/height ratio 1.2). At the aperture, these

measurements are 50 mm and ea. 65 mm, respeetively (width/height ratio 1.3; Figs lOE, 43D, F). The

mature eoneh is moderately eurved. The eonvex side of the eoneh eurvature is more strongly eurved

than the eoneave side, resulting in a maximum eoneh height at approximately the mid-length of the

mature body ehamber of 55 mm. Immediately adoral to the septum of truneation the eoneh appears to be

a slighty eonstrieted. The length of the phragmoeone and the numbers of ehambers of the phragmoeone

are not known, as the eoneh wall obseures details of the septa. The outermost layer of the shell is poorly

preserved, with no traees of the ornamentation remaining (Fig. 18G).

Four speeimens (PMU 26930-26933) represent truneated portions of the phragmoeone. All four

speeimens possess at their apieal end a deeply eurved septum of truneation. The eoneh height at the

septum of truneation varies between 23 and 28 mm and the adoral-most diameters lie between 36 and

38 mm, giving angles of expansion ranging from 6 to 8° (Fig. 42). The eoneh eross seetion in these

speeimens is depressed (width/heigh ratio 1.03-1.16) and they are more eurved than the mature fragment

(holotype). In speeimen NRM Mo 152301 the entire length eomprises seven ehambers. The suture is

nearly direetly transverse, but forms a shallow, wide lobe on the eonvex side of the eoneh eurvature. All

four speeimens are distinetively ornamented with fine longitudinal striae and fine, irregularly spaeed

growth lines, forming a wide sinus on the eonvex side of the eoneh eurvature.

Comparison

This speeies of Redpathoceras is similar to the type of the genus in having a depressed eoneh eross

seetion, but differs in having a larger adult size. The adult size is similar to that seen in R. bullatum sp.

nov., whieh in turn differs in having a eireular-eompressed eoneh eross seetion in premature growth

stages.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Redpathoceras magnum sp. nov.

um:lsid:zoobank.org:aet:5B495FBE-A8DE-4886-ABF4-FB22AC2D588F

Figs 42, 43A-C

Diagnosis

Mature body ehamber with slightly depressed eross seetion, moderately eurved with maximum eurvature

elose to aperture; infiated in lateral view with maximum height of ea. 70-80 mm at mid-length of body

ehamber; mature body ehamber margin at eoneave side of eoneh eurvature nearly straight on adapieal

two-thirds; eoneh eross seetion eompressed to eireular in earlier growth stages; premature eoneh

expands with angle of expansion 15°; mature eoneh with ea. five phragmoeone ehambers adoral of the

KROGER B., Cephalopods of the Boda Limestone

Fig. 43. Redpathoceras Flower, 1963, Kallholn, Boda Limestone. A-C. Redpathoceras magnum sp.

nov. A. PMU 26935, holotype; mature tmneated body ehamber, lateral view. B. Same speeimen,

view from antispihuneular side. C. PMU 26946, premature tmneated phragmoeone, lateral view.

D-F. Redpathoceras depressum sp. nov. D. PMU 26927, holotype; mature tmneated body ehamber,

lateral view. E. Same speeimen, view from antispihuneular side. F. PMU 26931, premature tmneated

phragmoeone, lateral view. Seale bar = 50 mm for all figures.

European Journal of Taxonomy 41: 1-110 (2013)

terminal septum of tmneation; diameter of terminal septum of truneation ea. 55 mm; ornamented with

fine longitudinal striae and irregularly spaeed transverse growth lines, whieh form a wide hyponomie

sinus.

Etymology

Latin magnus refers to the large adult size of this speeies.

Type material

Holotype

PMU 26935.

Paratypes

Fourteen paratypes (PMU 26936-26948), Kallholn, Dalama, Sweden, Boda Limestone, late Katian.

Type locality and horizon

Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late Katian, Ordovieian.

Description

The holotype is a fragment of a mature shell with a nearly eomplete body ehamber eombined with a

phragoeone eonsisting of five ehambers (Fig. 43A-B). The maximum width of the body ehamber is ea.

70 mm, the maximum height 68 mm at a position approximately at body ehamber mid-length (width/

height ratio 1.03). The eomplete length of the body ehamber is ea. 100 mm. The width of the body-

ehamber at the aperture is 70 mm and its height 63 mm (width/height ratio 1.11), at the base of the

body ehamber the width is 58 mm and the height 60 mm (width/height ratio 0.97). The body ehamber is

moderately eurved, with a narrower eurvature in adapertural seetions.

The eross seetion of the aperture is slightly depressed with a more rounded margin on the eonvex side

of eoneh eurvature. The shell is thiekened at the aperture with a thiekness of ea. 2.5 mm, eompared with

a thiekness of 1.3 mm at body ehamber mid-length. The surfaee of the shell is poorly preserved but

apparently smooth.

The phragmoeone has a length of 40 mm and expands with an angle of 19°. The four adoral ehambers

are shallow with a depth 0.15 that of the eorresponding eoneh height; their septa are simple and eap

shaped, with a shallow eonvexity, whilst the sutures are direetly transverse, but slightly oblique and

projeeting toward the aperture on the eoneave side of the shell.

The septum of truneation is deeply eonvex, its depth is sueh that it is almost equal to the depth of the

next two ehambers. The siphuneular perforation is narrow, with a diameter of ea. 3 mm (ea. 0.07 of

eorresponding eoneh height) and positioned eeeentrieally at a distanee of 8 mm from eoneh margin on

eonvex side of eoneh eurvature (SPR 0.18).

PMU 26942 is the largest fragment assigned to this speeies. It is a fragment of a body ehamber with a

maximum width of 78 mm and a maximum height of 70 mm (width/height ratio 1.11). The length of the

body ehamber is 100 mm. The shell surfaee is ornamented with faint, irregularly spaeed rounded striae

or growth lines whieh form a broad, shallow hyponomie sinus on the eonvex side of the shell eurvature.

In well preserved fragments of earlier growth stages with eoneh heights of less than 50 mm, the shell

surfaee is ornamented with irregularly, ea. 0.5-1 mm distant longitudinal striae and irregularly spaeed

growth lines that form a wide u-shaped hyponomie sinus on the eonvex margin of the shell (Fig. 43C).

KROGER B., Cephalopods of the Boda Limestone

Remarks

Five speeimens (PMU 26945-26947; NRM Mo 8795, 152300) are interpreted as tmneated parts of

the phragmoeone (see, e.g.. Fig. 43C). All five speeimens possess at their apieal end a deeply eurved

septum of tmneation. Speeimens NRM Mo 8795 and 152300 possess seven and eight ehambers,

respeetively. The eoneh height at the septum of tmneation varies between 36 and 45 mm and the adoral-

most diameters are 55 mm, resulting in angles of expansion of 14-15°(Fig. 42). The eoneh eross seetion

in these speeimens is slightly eompressed to eireular and they are more eurved longitudinally than the

mature fragments. The suture is nearly direetly transverse, but forms a shallow, wide lobe on the eonvex

side of the eoneh eurvature. The assignment of these fragments to R. magnum sp. nov. is justified by

their similar eoneh eross seetion and by the sizes of their adoral-most septa, whieh agree well with the

size of the septum of tmneation of the mature stage of the holotype.

Based on the fragments of different growth stages a eoneh ean be reeonstmeted, that, if it had not been

tmneated at several stages, would possess an angle of expansion of ea. 15° in juvenile growth stages, a

rate of expansion of more than 20° at the adoral end of the phragmoeone and a deereasing height during

its final growth stages. The infiation of the body ehamber is a result of a nearly straight outline of the

shell margin at the antisiphuneular side of the eoneh during the initial stages of growth of the mature

body ehamber.

Comparison

This is a large speeies of Redpathoceras, its mature eoneh width being more than twiee that of the type

speeies. It differs from the type speeies in having a eoneh eross seetion whieh ehanges during growth

from eompressed to depressed. R. bullatum sp. nov. differs in having a smaller adult size and a less

infiated mature body ehamber, with a eoneave outline of the eoneh margin on the eoneave side of the

eoneh eurvature. In R. magnum sp. nov. the outline of the mature body ehamber at the antisiphuneular

side is nearly straight in the apieal two-thirds.

Stratigraphic and geographic range

Boda Limestone, late Katian, Dalama, Sweden.

Family Hebetoeeratidae Flower, 1941

Genus Parvihebetoceras Kroger, 2007

Type species

Parvihebetoceras wahli Kroger, 2007, from the Porkuni Formation, Himantian, Porkuni, Estonia, by

monotypy.

Diagnosis

Small longieonie orthoeones with slightly depressed or eireular eross seetion; tmneated adult shell nearly

tubular with few, elosely spaeed, shallow eoneave septa possessing straight, direetly transverse sutures;

eoneh surfaee smooth or ornamented with faint growth lines; septum of tmneation oeeurs at a eoneh

diameter of about four to five millimeters; adult eross seetion diameter approximately seven millimeters;

siphuneular diameter approximately one-tenth of eoneh diameter; siphunele positioned between eentre

of eoneh and eoneh margin; siphuneular diaphragm present slightly adorally of the septum of tmneation;

septal neeks are asymmetrie, more elongated at ventral side, aehoanitie and suborthoehoanitie in juvenile

growth stages, suborthoehoanitie in adult growth stages; apex bullet-shaped, slightly eyrtoeonie, eieatrix

present, with diameter at first septum approximately 1.4 mm; no endosiphuneular deposits are known.

(Adopted from Kroger 2007.)

European Journal of Taxonomy 41: 1-110 (2013)

Parvihebetoceras wahli Kroger, 2007

Fig. 44

Parvihebetoceras wahli Kroger, 2007: 599, figs 4e, 7e, 9.

Diagnosis

Same as for genus, by monotypy.

Type locality and horizon

Porkuni, Estonia, Porkuni Formation, Himantian, Ordovieian.

Fig. 44. Parvihebetoceras wahli Kroger, 2007, PMU 26949, Kallholn, Boda Limestone. A. Lateral

view. B. Adapieal view. C. Median seetion with one septum preserved. Seale bar = 5 mm for all figures.

KROGER B., Cephalopods of the Boda Limestone

Material

One speeimen (PMU 26949), Kallholn, Dalama, Sweden, Boda Limestone, Boda Core Member, late

Katian, Ordovieian.

Description

The speeimen is a fragment of a body ehamber with one apieal ehamber of the phragmoeone (Fig. 44).

The eoneh is slightly eurved, the eross seetion eireular, 5.4-8.3 mm in diameter and 16 mm long (angle

of expansion 10°). The shell surfaee is partly preserved and smooth. Apieally the eoneh is tmneated with

a dome-shaped, deeply eonvex septum of tmneation. The adapieal surfaee of the septum of truneation

is rugged. The eonvexity of the septum is 3.5 mm. The tip of the septal dome is slightly subeentral, off

the eenter of the eoneh in direetion toward the eonvex side of the eoneh eurvature. A seeond septum is

preserved, ea. 4 mm adorally of the septum of truneation, whieh is less eonvex and with a subeentral septal

perforation (Fig. 44C). The shape of the septal neek is poorly preserved, but probably was aehoanitie

or very short suborthoehoanitie; it appears longer on the prosiphuneular side of the eoneh. Parts of the

eonneeting ring are preserved, whieh indieate a slightly expanded siphuneular segment. Beeause of

the poor preservation of the internal details, the presenee or absenee of eameral deposits is diffieult

to evaluate, but thin hyposeptal deposits appear to be present at the adoral septum (Fig. 44C) and the

rugged surfaee of the septum of truneation may be interpreted as the surfaee of episeptal deposits.

Remarks

The deeply eonvex, dome-shaped septum of truneation, the shape of the septal neeks and the position

and shape of the siphunele are diagnostie eharaeters of Parvihebetoceras. The eoneh size of the Boda

speeimen is identieal to that of Parvihebetoceras wahli Kroger, 2007 from the Porkuni Formation of

northern Estonia. P. wahli reaehes its adult size with a diameter of ea. 7 mm and has a septum of

truneation at diameters of ea. 5 mm. Beeause of the general similarity of the Boda speeimen with the

Estonian speeimens deseribed in Kroger (2007), it is regarded as eonspeeifie with P. wahli. However,

the Estonian speeimens of P. wahli appear slightly more brevidomie and have slightly smaller adult

sizes.

The speeimen deseribed herein shows features that ean be interpreted as hyposeptal deposits on the

adoral septum. However, beeause of the poor preservation of the internal eharaeters, it is impossible to

evaluate if these are primary or seeondary deposits. Therefore, they are not ineluded within the diagnosis

of the speeies.

The rough, poorly preserved surfaee of the septum of truneation is similar to that in the middle Silurian

Sphooceras Flower, 1962, but in Sphooceras the shape of the septal neeks and siphunele differ and

heavy eameral deposits are developed, whieh are absent in Parvihebetoceras.

Order, family, genus and speeies indet. A

Figs 4D, 18A

Material

Speeimen PMU 26950, Kallholn, Siljan Distriet, Sweden; Boda Limestone, Boda Core Member, late

Katian, Late Ordovieian.

Description

The speeimen is a nearly eomplete fragment of a body ehamber 110 mm long; parts of the basal

septum are preserved, as are parts of the aperture (Fig. 4D). The eoneh is slightly eurved and inereases

from ea. 55 to 75 mm in height and is 50 mm wide at the base (angle of expansion 13°, width/height ratio

European Journal of Taxonomy 41: 1-110 (2013)

0.91). The conch opens gradually. The conch cross section is subrectangular with lateral flanks and anti-

and prosiphuncular surfaces. The position and shape of the siphuncle cannot be determined. The shell

is ornamented with distinctive transverse annuli, which are slightly irregularly spaced (distance ca. 3-5

mm) and form a broad shallow sinus on the convex side of the conch curvature (Fig. 18A). Additionally,

a number of 8-10 crenulated and frilled lirae run parallel to the annulations within the distance of one

cycle of annulations. On the inner surface of the shell a distinctive wrinkle layer is preseverved

Remarks

Because no closely similar cephalopod conch is known from the Late Ordovician and no details of

the position and the shape of the siphuncle is preserved, no determination, even at the ordinal level, is

possible. The ornamentation and slight curvature of the shell might indicate an affinity with a member

of the Dawsonoceratidae or Barrandeoceridae.

Discussion

Remarks the evolution of the Ascocerida

Several cephalopod species with truncated conchs occur in the Boda Limestone. These are morphologically

transitional between typical ascocerids such as Billingsites Hyatt, 1884 and large gyroconic non-

truncated forms such as Warburgoceras gen. nov., traditionally assigned to the Uranoceratidae. Within

the Boda Limestone a nearly continuous morphological transition may be drawn between the un¬

truncated curved Warburgoceras gen. nov., possessing a nearly tubular mature body chamber and the

truncated Redpathoceras with its inflated mature body chamber. The strongly inflated body chamber

of Probillingsites Foerste, 1928 and of Schuchertoceras Miller, 1932 has adventitious septa (Fig. 44).

When comparing the Boda Limestone cephalopods, exclusively, an unambiguous reconstruction of the

origin of the ascocerids may be hypothesised such that ascocerids originated from strongly curved forms

related to Uranoceras Hyatt, 1884 and Warburgoceras gen. nov. (Fig. 44).

This contrasts with earlier hypotheses. Previously, only the juvenile conchs of Ascoceras Barrande,

1847 were known (e.g., Lindstrbm 1890). In Ascoceras the juvenile conch is slender, orthocerid-like,

and only slightly curved. Based probably on the detailed reconstructions of the Mid Silurian Ascoceras,

Kesling (1961) reconstructed an orthocerid-like, slender and widely curved juvenile shell in Billingsites

and Probillingsites. Generally, a slender, nearly orthoconic shell was considered to be a synapomorphy

of the lineage Probillingsites-Ascoceras lineage (Flower 1941: flg. 1). The Mid Ordovician truncated

orthocone Hebetoceras Flower, 1941 was considered central in this reconstruction.

Hebetoceras in turn was regarded as the hypothetical descendent of another Mid Ordovician truncated

form described by Flower (1941), the relatively large and cnr\Q&Montyoceras Flower, 1941. Montyoceras

was considered the ancestral ascocerid (Flower 1941, 1963). In Flower’s phylogenetic reconstructions,

MontyocerasAike cyrtocones evolved into Hebetoceras-like orthoceracones that Anally evolved into the

highly specialized H^cocera^'-like forms.

The occurrence of curved truncated forms in the Late Ordovician Boda Limestone suggests that

Hebetoceras did not lie in the direct ancestry of the Ascoceras lineage. Instead, an early divergence must

be assumed between slender orthoconic truncated forms and cyrtoconic truncated forms. The large and

considerably curved Montyoceras titaniforme Flower, 1941 is much more similar to the Boda ascocerids

than any orthocone.

Flower (1941: 543) had already emphasized that several Mid-Late Ordovician depressed cyrtocones

existed, which were probably closely related to Montycoceras. The internal characters of most of these

cyrtocones are poorly known. Within this group the truncated Katian Redpathoceras Flower, 1963, now

KROGER B., Cephalopods of the Boda Limestone

known in greater detail from the Boda Limestone, represents one sueh genus. It is highly probable that

the late Katian non-tmneated Deckeroceras Foerste, 1935 from the Femvale Formation of Oklahoma

and Warburgoceras gen. nov. from the Boda Limestone are elosely related to Redpathoecras and

Montycocems. This group of four genera is eharaeterized by relatively large eurved shells and, most

likely, a fine longitudinal ornament (eompare Figs 18F and 18G), as well as a ventrally, eeeentrieally

positioned siphunele with expanded siphuneular segments and aehoanitie to suborthoehoanitie septal

neeks with very thin eonneeting rings.

Warburgoceras longitudinale (Angelin in Angelin & Lindstrom, 1880) eomb. nov., the type of

Warburgoceras gen. nov., is very similar to the truneated Redpathoceras. The eurved shell, the

ornamentation, the position and form of the siphunele, and the short septal neeks are nearly identieal in

both genera (eompare Fig. 40 and Mutvei 1957: fig. 17.1). Earlier this speeies, whieh was deseribed in

great detail by Mutvei (1957), was assigned to Uranoceras Barrande, 1866 (Mutvei 1957; Dzik 1984).

Here it is regarded as a distinet genus, mainly beeause of moderate differenees in the shell outline

(see below). Without doubt, both speeies are elosely related and represent a relatively long ranging

evolutionary lineage, the Uranoeeratidae.

The affinities of this lineage were disputed. The Uranoeeratidae were assigned to the Barrandeoeerida

by Sweet (1964a) and to the Centroeeratina by Dzik (1984), but a elose affinity with aseoeerids was

never proposed. The similarity between Warburgoceras gen. nov., Uranoceras, Redpathoceras,

Probillingsites and Billingsites may be a eoineidenee, but a more parsimonious solution would be to

assume a elose phylogenetie relationship between these genera. Here, it is assumed that a group of

non-tmneated Uranoceras-\ikQ eyrtoeones gave rise to the tmneated Montycoceras/Redpathoceras-\ikQ

forms, and the typieal aseoeeratids subsequently evolved from these forms. The uranoeeratids and the

aseoeerids originated from the same group of Mid Ordovieian non-tmneated eyrtoeones. The entire

group of tmneated and un-tmneated eyrtoeones is eharaeterized by a ventrally, eeeentrieally positioned

siphunele, whieh is slightly expanded within the ehambers and has a very thin eonneeting ring. The

fine longitudinal ornamentation is probably also a synapomorphy for this group. Moreover, a similar

very eharaeteristie ventromyarian periphraet is present in the uranoeeratids Warburgoceras gen. nov.,

Siljanoceras gen. nov. and in the aseoeeratid 5/7//>2g^/te (eompare Mutvei 1957; Sweet 1959).

This assumption opens a new perspeetive, not only on the origin of the Aseoeeratida, but also on the

phylogenetie relationships of the Barrandeoeeratidae. Formerly, the origin of the Aseoeeratida was

sought for in orthoeonie forms sueh as Sactorthoceras (Flower 1941). The eyrtoeonie and eoiled Mid

Ordovieian Barrandeoeeratidae and Aspidoeeratidae were not even eonsidered as potential aneestors

or as being elosely related to the Aseoeerida. These two families were plaeed in the Barrandeoeerida

by Sweet (1964a), and in the Tarphyeerida by Dzik (1984) and Flower (1984). Neither Dzik (1984) or

Flower (1984) aeeepted the order Barrandeoeerida, regarding the differenees in the thiekness of the

eonneeting ring between typieal Tarphyeeratida and Barrandeoeerida as insuffieiently signifieant for the

distinetion of an order.

By eontrast, Mutvei (2002) plaeed emphasis on the importanee of the stmeture of the eonneeting ring for

reeonstmeting the phylogenetie relationships of higher groups and distinguished between an Orthoceras-

type eonneeting ring and a Nautilus-typQ eonneeting ring. The Tarphyeerida are eharaeterized by a

Nautilus-typQ eonneeting ring (Mutvei 2002; Mutvei & Dunea 2011). The eonneeting ring of the the

Late Silurian uranoeeratid Cumingsoceras complanatus (Hisinger, 1831) was interpreted by Mutvei

& Dunea (2011) as being of the Orthoceras-tyv^, whieh may be taken to indieate an affinity with the

Orthoeerida. Mutvei & Dunea (2011) argued for an assignment of Cumingsoceras complanatus and

the Uranoeeratidae within the Barrandeoeerida and eonsidered the Orthoceras-typQ eonneeting ring as

a diagnostie eharaeter of that order. The eonneeting ring of Redpathoceras in the Boda Limestone is

European Journal of Taxonomy 41: 1-110 (2013)

only poorly preserved, but a median seetion (Fig. 40) reveals that it is thin, simple and resembles that of

Cumingsoceras complanatus and Warburgoceras longitudinale eomb. nov. At present, however, there is

no positive evidenee for a ealeified perforated layer in Redpathoceras.

In the eontext of the phylogenetie seheme presented here (Fig. 45), the nature of the eonneeting ring

might suggest that Aseoeerida and Uranoeeratidae were both deseendants of the Orthoeerida. This

eoneurs with the earlier hypothesis of Flower (1941) of an orthoeerid aneestor of the Aseoeerida.

It is, however, in eonfliet with the observations of Mutvei (2012) regarding the strueture of the

eonneeting ring of Choanoceras Lindstrom, 1890. Choanoceras is a Mid Silurian aseoeerid, whieh is

eonsidered as representing an early offshoot of the Montyoceras-Hebetoceras-Billingsites lineage by

Furnish & Glenister (1964a) and Dzik (1984). Mutvei (2012) interpreted the strueture of the siphunele

of Choanoceras as being of the Nautilus-ty^Q and questioned the idea of an orthoeerid origin of the

Aseoeerida. Instead, he found a greater similaritiy of Choanoceras to the Diseosorida in terms of the

strueture of the eonneeting ring and suggested a elose aseoeerid-diseosorid relationship.

443.7

460.9

471.8

Hebetoceratidae

Ascoceratidae

Uranoeeratidae

Upper Ord.

Hir.

Katian

Sand-

bian

Middle Ord.

Darri-

wilian

Dap-

inqian

Fig. 45. Hypothesis about the phylogenetie relationship of seleeted Aseoeerida and Barrandeoeerida.

Note the phylogenetie trend of deeoiling in aseoeerids. The diversifieation of aseoeerids oeeurred

during the late Mid Ordovieian. Star = truneation; 1 = thin subeentral siphunele with orthoeerid-like

thin eonneeting ring; 2 = uneoiling. The elose phylogenetie relationship between the uranoeeratid

Warburgoceras gen. nov. and aseoeerids is based on the general similarity of shell shape, ornamentation,

sipho-position and eonneeting ring shape of Redpathoceras Flower, 1963. Note also that Montyoceras

titaniforme Flower, 1941 is larger, more rapidly expanding and more strongly eoiled than the type

of the genus, and thus mueh more similar to Redpathoceras. Figures of Hebetoceras Flower, 1941;

Montycoceras Flower, 1941; Probillingsites Flower, 1941; Billingsites Hyatt, 1884; Schuchertoceras

Miller, 1932; ?indAscoceras Barrande, 1847 are modified from Kesling (1961). Figures of Choanoceras

Lindstrom, 1890 are based on Furnish & Glenister (1964a); those of Deckeroceras Foerste, 1935 and

Barrandeoceras Flower, 1950 are based on Sweet (1964a).

100

KROGER B., Cephalopods of the Boda Limestone

If Mutvei’s (2012) and Mutvei & Dunea’s (2011) eonelusions are eorreet and the eonneeting ring of

Choanoceras is of the Nautilus-\yx^Q and Redpathoceras and Cumingsoceras are of the Orthoceras-

type, the Aseoeerida and the evolution of truneation must be regarded as polyphyletie. This seems very

improbable, as all other eharaeters suggest a elose affinity between the straight and eurved aseoeerids

and the Uranoeeratidae.

Speeifieally, the position of the siphunele (near eonvex eoneh margin in aseoeerids/uranoeeratids, near

eoneave margin in diseosorids), the shape of the periphraet (ventromyarian in aseoeerids/uranoeeratids,

with multiple attaehment sears in diseosorids/oneoeerids, see Sweet 1959) and the features of the

eonneeting ring (thin and simple, probably of Orthoceras-typQ, and empty in premature aseoeerids/

uranoeeratids, thiek and often with endosiphuneular deposits in diseosorids and oneoeerids) speak

against a elose aseoeerid-diseosorid relationship.

The preservation of the Silurian forms deseribed by Mutvei & Dunea (2011) is rather imperfeet and

the illustrated struetures eould also be interpreted as very thin eonneeting rings of the Nautilus-type

(this is espeeially the ease for the figures la-e, and If of Mutvei & Dunea 2011) with a non-preserved

inner organie fibrous layer. There is no positive evidenee for a ealeified perforated layer in the figured

speeimen and the blaek layer of Mutvei & Dunea (2011) eould be interpreted as a diagenetieally altered

and expanded spherulitie prismatie layer. Similarily, the eonneeting ring struetures of Choanoceras

figured in Mutvei (2012) are imperfeetly preserved, and the bulletes, figured in Mutvei (2012: fig. 8a, b)

eould alternatively be interpreted as an effeet of the plane in whieh the speeimen was eut, whieh appears

to be oblique to the axis of the siphunele.

In eonelusion, the new data from the Boda Limestone indieates that aseoeerid aneestors were eyrtoeones

possessing eeeentrie, slightly expanded siphuneles with thin eonneeting rings and short septal neeks.

These aneestors most probably belong to the Mid Ordovieian Barrandeoeeratidae or Aspidoeeratidae.

The strueture of the eonneeting ring of the Aseoeerida is still poorly known and largely subjeet to

interpretation. Ineonsisteneies in eurrent hypotheses of the evolution of the Aseoeerida result from

ineomplete knowledge of the eonneeting ring strueture of the group of eoiled and eurved Mid-Late

Ordovieian eephalopods that were assigned within the Barrandeoeerida by Sweet (1964a). Future

researeh needs to foeus on the analysis of the strueture of the eonneeting ring of these forms.

Conclusions

The taxonomie revision of the eephalopods in the museum eolleetions of the NRM and the PMU

reveals the presenee of 62 speeies, aeross 32 genera, eomprising eephalopods of the orders Aseoeerida,

Barrandeoeerida, Diseosorida, Endoeerida, Oneoeerida, Orthoeerida and Tarphyeerida (Tables 2,

3). Of these, three genera and 16 speeies are new. Additionally, the revision led to a number of new

eombinations (Table 4).

The number of eephalopod genera known from the Boda Limestone is almost equal to that of the bivalves

(34, see Isberg 1934) and is larger than the number of strophomenid braehiopod genera (25, see Coeks

2005). Bearing in mind that eephalopods were among the top predators of the Boda reef eeosystem,

their high diversity indieates an extremely rieh fauna of organisms lower in the food ehain. Indeed,

extremely high Boda trilobite diversities were reported, and very high gastropod diversities have been

estimated by Ebbestad & Hogstrom (2007). However, the main food resourees of the Boda eephalopods

are probably not preserved. Crustaeeans, whieh have a poor preservation potential (Plotniek 1986), are

the main eomponent in the diet of modem eephalopods (Glynn & Enoehs 2011). The most co mm on and

the most diverse Boda eephalopods are orthoeerids (Table 3), whieh are interpreted as vertieal migrants

in the water eolumn (Westermann 1998; Kroger et al. 2009). Therefore, a eephalopod feeding within

the water eolumn is likely (Kroger et al. 2009). This eould be interpreted as indireet evidenee for a high

101

European Journal of Taxonomy 41: 1-110 (2013)

Table 2. Number of specimens in the collections of the NRM and PMU from the most important Boda

Limestone localities. Note that sample sizes are not always identical with number of specimens examined

and described in the text, because not all specimens in the collections of the NRM have been examined

in detail. (A&L = Angelin & Lindstrom)

species

Kallholn

Osmnnds-

berget

Unskars-

heden

Rattvik

Skal-

berget

Ost-

bjorka

Beloitoceras siljanense Frye, 1987

Beloitoceras sinuososeptatum (Roemer, 1861)

Beloitoceras sp.

Bodoceras torticoni Frye, 1982

Cameroceras regulus (Eichwald, 1860)

Cameroceras hasta (Eichwald, 1857)

Cameroceras turrisoides sp. nov.

Charactoceras kallholnense Frye, 1982

Charactoceras raettvikense Frye, 1982

Charactoceras suecicum Frye, 1982

Charactoceras triangulum Frye, 1982

Cyrtorizoceras thorslundi sp. nov.

Dalecarlioceras bodense Frye, 1987

Dalecarlioceras constrictum Frye, 1987

Dalecarlioceras dalecarlicum (Frye, 1987)

Danoceras broeggeri (Strand, 1934)

Danoceras scandinavicum (Strand, 1934)

Dawsonoceras fenestratum (Eichwald, 1860)

Dawsonoceras stumburi sp. nov.

Dowlingoceras kallholnense Frye, 1987

Diestoceras parallelum Frye, 1987

Discoceras antiquissimum (Eichwald, 1842)

Discoceras roemeri Strand, 1934

Geisonoceras wegelini (Angelin in A&L, 1880)

Geisonoceras sp. A

Gorbyoceras alternestriatum (Strand, 1934)

Gorbyoceras sp. A

Gorbyoceras sp. B

Parvihebetoceras wahli Kroger, 2007

Isorthoceras angelini sp. nov.

Isorthoceras curvilineatum sp. nov.

Isorthoceras dalecarlense Kroger et at, 2011

Isorthoceras cf. elongatocinctum (Portlock, 1843)

Isorthoceras heroyense (Strand, 1934)

Isorthoceras junceum (Hall, 1847)

Isorthoceras leptaenarum (Angelin in A&L, 1880)

Isorthoceras suave (Angelin in A&L, 1880)

Isorthoceras wahlenbergi Niko, 2008

Kallholnoceras cornutum Frye, 1987

Kiaeroceras heroyense Strand, 1934

102

KROGER B., Cephalopods of the Boda Limestone

Table 2, eontinued.

Nathorstoceras kallholnense sp. nov.

Nathorstoceras adnatum sp. nov.

Ordogeisonoceras foerstei (Strand, 1934)

Palaeodawsonocerina senckenbergi (Teiehert, 1930)

Palaeodawsonocerina sp. A

Palaeodawsonocerina'! nicolletoides sp. nov.

Pleurorthoceras osmundsbergense sp. nov.

Probillingsites scandinavicum sp. nov.

Redpathoceras bullatum sp. nov.

Redpathoceras depressant sp. nov.

Redpathoceras magnum sp. nov.

Redpathoceras sp.

Schuchertoceras bodense Frye, 1982

Schuchertoceras fryi sp. nov.

Schuchertoceras troedssoni (Foerste, 1929)

Siljanoceras varians sp. nov.

Siljanoceras sp. A

Strandoceras sphinx (Schmidt, 1858)

Striatocycloceras isbergi sp. nov.

Striatocycloceras sp.

Tyrioceras warburgae Frye, 1982

Tyrioceras kjaerulfi Strand, 1934

Warburgoceras longitudinale (Ang. in A&L, 1880)

Order, gen. et sp. indet 1

abundanee and diversity of nektonie and planktonie emstaeeans in the Boda reef waters. High nutrient

levels of the Boda reef waters are probably also indieated by the high abundanee of suspension feeders,

sueh as braehiopods (whieh is expressed in the old name “Leptaena Limestone” for the Boda Limestone;

see, e.g., Coeks 2005), andbyssate bivalves (Isberg 1934).

Despite the extraordinarily high eephalopod diversity (a detailed diversity analysis and eomparison

with eontemporary assemblages is in preparation and will be published in a fortheoming paper by the

author) and the relatively large number of observed speeimens (more than 500), not a single aetinoeerid

eephalopod has been reeorded in the Boda Limestone. Aetinoeerids are abundant in eontemporaneous

eephalopod assemblages of low palaeolatitudes and in Late Ordovieian reef settings and are present

in eontemporaneous assemblages of Norway and Estonia (Teiehert 1930; Strand 1934; Kroger et al.

2009). This absenee or extraordinary rarity is provisionally interpreted as evidenee for a depositional

environment in relatively deep waters or in relatively eold waters. However, a detailed faunal analysis

whieh ineludes absolute depth measurements based on hydrostatie strength estimates of the eephalopod

shells is required for a more substantiated interpretation, whieh is in preparation and will be published in

a fortheoming paper. Moreover, a reliable diversity analysis ean only be based on subsampled diversity

estimates.

The taxonomie revision presented here elearly demonstrates the importanee of eephalopods in the Boda

reef eeosystem and their potential to eontribute to a better understanding of the proeesses that led to the

formation of the Boda reefs.

103

European Journal of Taxonomy 41: 1-110 (2013)

Table 3. Systematic classification of cephalopods from the Boda Limestone, late Katian-Himantian,

Dalama, Sweden and sample size.

Order

Family

Genus

sample size

Ascocerida

Hebetoceratidae

Parvihebetocems

Probillingsitidae

Probillingsites

Redpathoceras

Schuchertoceratidae

Schuchertoceras

sum Ascocerida

Barrandeocerida

Apsidoceratidae

Bodoceras

Charactoceras

Uranoceratidae

Siljanoceras

Warburgoceras

sum Barrandeocerida

Discosorida

Cyrtogomphoceratidae

Kiaeroceras

Strandoceras

sum Discosorida

Endocerida

Endoceratidae

Cameroceras

sum Endocerida

Lituitida

Eituitidae

Tyrioceras

sum Lituitida

Oncocerida

Oncoceratidae

BeJoitoceras

Cyrtorizoceras

Dalecarlioceras

Diestoceratidae

Danoceras

Dawlingoceras

Diestoceras

Karoceratidae

Kallholnoceras

sum Oncocerida

Orthocerida

Dawsonoceratidae

Dawsonoceras

Geisonceratidae

Geisonoceras

Proteoceratidae

Gorbyoceras

Isorthoceras

164

Geisonceratidae

Ordogeisonoceras

Dawsonoceratidae

Palaeodawsonocerina

Orthoceratidae

Pleurorthoceras

Striatocycloceras

Proteoceratidae

Transorthoceras

Erititidae

Nathorstoceras

sum Orthocerida

329

Tarphycerida

Discoceratidae

Discoceras

sum Tarphycerida

104

KROGER B., Cephalopods of the Boda Limestone

Table 4. List of new name eombinations proposed in this paper. (A&L = Angelin & Lindstrom)

Original name New combination, herein

Cyrtorizoceras dalecarlicum Frye, 1987

Cyrtoceras longitudinale Angelin A&L, 1880

Endoceras akpatokeme Foerste & Cox, 1936

Endoceras coxi Foerste & Cox, 1936

Endoceras windriverense Miller, 1932

Geisonoceras foerstei Strand, 1934

Geisonoceras heroyense Strand, 1934

Michelinoceras dnestrovense Balashov, 1975

Monomuchites bacotense Balashov, 1975

Orthoceras elongato-cinctum Portlock, 1843

Orthoceras leptaenarum Angelin, />? A&L, 1880

Orthoceras suave Angelin in A&L, 1880

Orthoceras textumaraneum Roemer, 1861

Orthoceras wegelini AngQXin, /wA&L, 1880

Spyroceras alternestriatum Strand, 1934

Dalacarlioceras dalecarlicum (Frye, 1987)

Warburgoceras longitudinale (Angelin A&L, 1880)

Cameroceras akpatokense (Foerste & Cox, 1936)

Cameroceras coxi (Foerste & Cox, 1936)

Cameroceras windriverense (Miller, 1932)

Ordogeisonoceras foerstei (Strand, 1934)

Isorthoceras heroyense (Strand, 1934)

Isorthoceras dnestrovense (Balashov, 1975)

Nathorstoceras bacotense (Balashov, 1975)

Isorthoceras elongatocinctum (Portlock, 1843)

Isorthoceras? leptaenarum (Angelin A&L, 1880)

Isorthoceras suave (Angelin A&L, 1880)

Gorbyoceras textumaraneum (Roemer, 1861)

Geisonoceras wegelini (Angelin A&L, 1880)

Gorbyoceras alternestriatum (Strand, 1934)

Acknowledgments

This paper eould not have been realised without the ongoing support and help of Jan Ove Ebbestad,

Uppsala, Sweden. His engagement offered me the possibility to work several months at the PMU and to

use and install the equipment needed for this work. Many thanks also to Stefan Bengtson of the NRM

who granted me aeeess to the paleozoologieal eolleetions, and to Jonas Hagstrom of the NRM for his

support during my visits in Stoekholm. The diseussions with Harry Mutvei, Stoekholm inspired me to

develop hypotheses about the origin of the Aseoeerida. David Evans, Peterborough, UK and Kathleen

Histon, Varese, Italy thoroughly reviewed an earlier draft of the manuseript, improved the English and

with their eomments helped to inerease the quality of this work. I am grateful for their support.

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Manuscript received: 10 May 2012

Manuscript accepted: 21 December 2012

Published on: 27 March 2013

Topic editor: Christian de Muizon

Desk editor: Danny Eibye-Jacobsen

Printed versions of all papers are also deposited in the libraries of the institutes that are members of

the EJT consortium: Museum National d’Histoire Naturelle, Paris, France; National Botanic Garden

of Belgium, Meise, Belgium; Royal Museum for Central Africa, Tervuren, Belgium; Natural History

Museum, Eondon, United Kingdom; Royal Belgian Institute of Natural Sciences, Bmssels, Belgium;

Natural History Museum of Denmark, Copenhagen, Denmark.

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