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BULLOUGH, W. S. 1960. Practical invertebrate anatomy. 2nd ed. London: Macmillan.

FISCHER, P. H. 1948. Données sur la résistance et de la vitalité des mollusques. Journal de conchyliologie 88:

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FISCHER, P. H., DUVAL, M. & RAFFY, A. 1933. Etudes sur les échanges respiratoires des littorines.

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KOHN, A. J. 1960a. Ecological notes on Conus (Mollusca: Gastropoda) in the Trincomalee region of Ceylon.

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KOHN, A. J. 19606. Spawning behaviour, egg masses and larval development in Conus from the Indian Ocean.

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THIELE, J. 1910. Mollusca. B. Polyplacophora, Gastropoda marina, Bivalvia. In: SCHULTZE, L. Zoologische

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Fig. 1. A. Aplidium flavolineatum, showing both red and grey colour forms. Red form

photographed at 8 m depth in False Bay, grey form in intertidal rock pool, Isipingo.

B. Aplidium mernooensis, Sodwana Bay, 28 m. C. Aplidium tubiferus sp. nov., Sodwana

Bay, 21 m. D. Polyclinum isipengense, intertidal rock pool, Isipingo. E. Pseudodistoma

africanum, showing both orange-red and white morphs, Sodwana Bay, 24-34 m.

F. Pseudodistoma delicatum sp. nov., Sodwana Bay, 24 m. G. Riterella solida sp. nov.

Oudekraal, Cape Peninsula, 10 m. H. Eutherdmania divida sp. nov., intertidal rock pool,

Isipingo. I. Eudistoma illotum, intertidal rock pool, False Bay.

Fig. 2. A. Polyclitor africanus, Durban outer anchorage. B. Cystodytes dellechiajei, under

rock on intertidal pool, False Bay. C. Distaplia skoogi, Miller’s Point, False Bay, 15 m.

D. Sycozoa arborescens, intertidal cave in Old Harbour, Hermanus. E. Sigillina digitata, in

rock pool, False Bay. F. Clavelina lepadiformis, Knysna Estuary, growing on jetty.

G. Trididemnum cerebriforme, Oudekraal, Cape Peninsula, 0-15 m. H. Didemnum

globiferum sp. nov., Kommetjie, Cape Peninsula, intertidal. =

Fig. 3. A. Didemnum leopardi sp. nov., Sodwana Bay, 14-15 m. B. Didemnum obscurum,

Sodwana Bay, 15 m. C. Didemnum rodriguesi, Sodwana Bay, intertidal to 22 m.

D. Polysyncraton aspiculatum, Sodwana Bay, 14-15 m. E. Polysyncratom millepore,

Sodwana Bay, 8-12 m. F. Ascidia caudata, False Bay, low intertidal. G. Botryllus closionis

sp. nov., Sea Point, Cape Town, in low intertidal pool. H. Botryllus elegans, growing on

fronds of Epymenia obtusa in intertidal rock pool, Sea Point, Cape Town.

Fig. 4. A. Botryllus gragalis, under jetty, Saldanha Bay. B. Botryllus meandrius, under

intertidal boulder, Sea Point, Cape Town. C. Botryllus magnicoecus, Miller’s Point, False

Bay, 2-10 m, growing on Pyura stolonifera. D. Botryllus mortenseni, intertidal rock pool,

Isipingo. E. Symplegma bahraini, Sodwana Bay, 30-33 m. F. Stolonica multitestis sp.

nov., intertidal rock pools, Isipingo. G. Gynandrocarpa placenta, Oudekraal, Cape

Peninsula, 6 m. H. Polycarpa insulsa, in rock pools, Isipingo.

SOUTH AFRICAN ASCIDIANS

CLAUDE MONNIOT, FRANCOISE MONNIOT

Biologie des Invertébrés Marins, Muséum national d’Histoire naturelle,

55 rue Buffon, 75005 FR Paris

CHARLES L. GRIFFITHS

Zoology Department and Marine Biology Research Institute,

University of Cape Town, Rondebosch, South Africa

MICHAEL SCHLEYER

Oceanographic Research Institute, Marine Parade, Durban, South Africa

(With 60 figs)

[MS accepted 10 November 2000]

ABSTRACT

Tunicates are described from the shallow waters of South Africa from Saldanha Bay to

Sodwana Bay, and include 22 new species. A list of ascidians previously recorded from this

area is also presented with relevant comments. The new material represents only part of the

fauna as few stations were investigated and many specimens could not be identified as they

were single, immature or without larvae. A transition was found between the tropical

KwaZulu-Natal area and the Eastern and Western Cape provinces, but no significant

differences were noted between the western (Atlantic Ocean) and eastern (Indian Ocean) sides

of the Cape. Cosmopolitan fouling species inhabit harbours.

CONTENTS

PAGE

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Ann. S. Afr. Mus. 108 (1), 2001: 1-141, 60 figs.

1 ANNALS OF THE SOUTH AFRICAN MUSEUM

INTRODUCTION

Among the 82 species collected and described in this study, 22 are new to

science. The order Aplousobranchia is dominant with 44 species, the order

Phlebobranchia is represented by only eight species, and the order Stolido-

branchia by 30 species. It is likely that these numbers greatly under-represent

the ascidian fauna of South Africa, even when the 63 species previously

described are included. Among the species recently collected, several were not

mature and cannot be identified, but they do not belong with certainty to any

already known taxa. Several species were collected by chance, hidden between

other closely packed ascidians, often covered with sand.

Many of the newly collected ascidians represent new species, whereas

previously described forms have not been found again. This can be easily

explained. Both collections, recent and past, do not represent a systematic

inventory of the South African fauna but were the result of occasional

collections undertaken at distantly spaced stations. The ascidians described here

were collected on hard substrata, either at low tide or by SCUBA diving. All

previously described species were collected by dredging, often on soft bottoms,

sometimes in deep water at 200-400 m on the Agulhas Bank far from the shore.

Their collection was incidental to larger investigations undertaken during

famous oceanographic expeditions, such as the Valdivia, Challenger, Siboga or

Deutsche Tiefsee expeditions. Apart from this, the ascidians have never been the

subject of a local study. Many of the species already described came from more

northern locations along the African or Madagascan coasts, or from the

southern or western parts of Australia, and very few from the Antarctic.

With such a miscellany of data, it is not possible to draw conclusions about

the geographic distribution, or endemism rate of South African ascidians.

Nevertheless, a boundary appears to exist between the warmer waters of the

Indian Ocean and the Eastern and Western Cape provinces region, where

tropical species have not been recorded. The opposite is less evident, and

southern species have been encountered in KwaZulu-Natal and farther north, in

Mozambique and Tanzania. Some species are common to the Atlantic and

Pacific oceans. These are fouling species mainly encountered in harbours.

Among them are Cystodytes dellechiajei, Clavelina lepadiformis, Didemnum

psammathodes, Diplosoma listerianum, Ciona intestinalis, Ascidiella aspersa,

Botryllus schlosseri, Microcosmus squamiger, Styela canopus, Cnemidocarpa

humilis.

The algal bearing didemnids common to the Indo-Pacific region—Didemnum

molle, Lissoclinum bistratum, and Diplosoma virens—penetrate KwaZulu-Natal.

MATERIAL AND METHODS

The ascidians were fixed and preserved in 4 per cent formalin in sea water.

All identifications required dissection after removing the tunic. The organs were

stained with hemalum and dehydrated in ethyl and butyl alcohols for mounting

on microscope slides in a plastic medium. The China ink drawings were made

with a camera lucida. The tunic spicules and spinules were observed with a

scanning electron microscope Jeol 800. The type specimens of new species are

SOUTH AFRICAN ASCIDIANS 3

registered in the South African Museum. The additional material is stored in the

Museum National d’Histoire Naturelle Paris.

SYSTEMATICS

Family Polyclinidae

Aplidium circulatum (Hartmeyer, 1912)

Fig. 5

Amaroucium circulatum Hartmeyer, 1912: 349, pl. 39 (fig. 2), pl. 44 (fig. 6). Michaelsen,

1934: 130: Millar, 1955: 171; 1962: 122.

Material

One colony, Miller’s Point, False Bay, Cape Peninsula, 8-12 m (Griffiths

coll.).

Description

The colony has a hemispheric head on a conical peduncle narrowed at the

base. The tunic is encrusted with sand in the peduncle and between the zooid

systems. The oral siphons are arranged in circles around common cloacal

apertures. The zooids can be easily seen through the pale tunic when the colony

heads do not contain too much sand.

The zooids are very long, sometimes more than 15 mm (Fig. 5A). The six

oral lobes have a straight margin or a median slit. The cloacal languet may be

simple (Fig. 5D), but is more often divided into three unequal lobes (Fig. 5B,

C); it originates from the dorsal edge of the siphon. The thorax is long with

11-14 rows of stigmata (Fig. 5B, C). The stomach is almost spherical with

25-28 longitudinal folds on tranverse sections, some of them interrupted

(Fig. SE). An oblique protruding fold is present on the post-stomach (Fig. 5B).

The post-abdomen is very long (Fig. 5A). The ovary is located far from the

gut (Fig. 5B), followed by a double row of very numerous testis lobes reaching

the heart (Fig. 5A).

Several larvae are brooded in the posterior part of the cloacal cavity

(Fig. 5C). The trunk measures 0.75 mm. The ocellus and otolith are present.

The three adhesive papillae are well separated between four odd triangular

vesicles (Fig. 5F). In addition there are four round vesicles on each side and

some on the dorsal side, and several irregular ones along the ventral line.

Remarks and distribution

These specimens correspond well to Hartmeyer’s description and figures,

and to the type specimen (ZMB 2769) from St Francis Bay, South Africa, but

his colony was not mature. They also agree with Millar’s (1955) sample from

False Bay.

In 1962 Millar, following Michaelsen (1920b), hesitated concerning the

possible synonymy with Aplidium erythraeum (Michaelsen, 1921) a species

itself a synonym of A. flavolineatum (Sluiter, 1898a).

4 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 5. Aplidium circulatum. A. Entire zooid. B. Thorax, abdomen and anterior part of the

post-abdomen. C. Thorax and abdomen of a brooding zooid. D. Siphons of another zooid.

E. Detail of the stomach. F. Larva.

Aplidium circulatum and A. flavolineatum are indeed very closely allied.

They have in common circular systems, the same tunic consistency and shape of

the zooids, the cloacal siphon in a short tube, and an average of 12 rows of

stigmata. The differences are that A. circulatum has pedunculate colonies and

different larvae of a larger size and with fewer anterior vesicles.

We have also not found in this species the dark pigment cells found in the

zooid tissues of A. flavolineatum.

SOUTH AFRICAN ASCIDIANS 5

Aplidium crustatum F. Monniot sp. nov.

Fig. 6

Material

Holotype. SAM-A25841, Saldanha Bay (33°03’S 18°02’E), 1-2 m,

collected by C. and F. Monniot, 8 February 1996.

Other material. Several colonies, Miller’s Point (Cape Peninsula) and

Saldanha Bay; intertidal (Monniot coll.).

Description

Colonies densely impregnated with sand to form irregular pads, about

10 mm thick, encrusting rocks at the interface with sand in the bottom of pools,

or deeply embedded in rocky crevices. Their general consistency is hard and the

Fig. 6. Aplidium crustatum sp. nov. A. Thorax and abdomen. B. Other side of the same

abdomen. C-D. Anterior and posterior part of the post-abdomen. E. Larva.

6 ANNALS OF THE SOUTH AFRICAN MUSEUM

zooid openings cannot be seen among the sand grains. The colonies are tightly

attached to the substratum and cannot be torn off without damage. Some

colonies contain amphipods.

The zooids are particularly thin and elongated, with the post-abdomens

crossing each other in all directions. The oral siphon is short and narrow with

six pointed lobes (Fig. 6A). The cloacal siphon opens through a simple hole or

short tube and is located in front of the first row of stigmata. Its dorsal edge is

prolonged into a simple, stout, pointed languet (Fig. 6A). The thorax is narrow

with 12 rows of a small number of stigmata. The abdomen is as long as the

thorax and narrow (Fig. 6A, B). The stomach lies at mid-length of the gut loop

and its wall has 10-14 folds (Fig. 6A). It is followed by the annular post-

stomach. The anus opens at the level of the eighth row of stigmata. The post-

abdomen is very long. The ovary is far behind the gut loop (Fig. 6C), at least at

a distance equal to the abdomen length. The testicular vesicles are numerous, in

a simple row extending from the ovary to the heart (Fig. 6D).

Three larvae mature in the cloacal cavity. They are small with a trunk

0.4 mm long. Their three anterior adhesive papillae are short and well separated

with a continuous anterior crescent of small ampullae on each side (Fig. 6E).

Remarks

This species is characterized by colonies that are densely embedded with

sand, have no definite shape, and thin zooids about 10 mm long, irregularly

arranged, with a single line of testes.

Aplidium flavolineatum (Sluiter, 1898a)

Figs 1A, 7

Amaroucium flavolineatum Sluiter, 1898a: 30, pl. 1 (fig. 7), pl. 4 (fig. 12).

Aplidium flavolineatum: Millar, 1962: 120, fig. 2 (with synonymy).

non Aplidium flavolineatum: Monniot, F., 1987: 522, fig. 9F-I.

Material

Several colonies. From Saldanha Bay to Sodwana Bay, in rock pools and

down to 9 m (Griffiths, Schleyer and Monniot coll.).

Description

The colonies form soft, thin, gelatinous crusts or cushions varying in

colour: cream, pink, red or sometimes grey. The circular systems are always

obvious. Each oral aperture is circled with a white line. Although there is no

sand at the colony surface, there are often some sparse particles between the

systems inside the colony.

The zooids are very variable in size, increasing with the size of the colony

and linked to the length of the post-abdomen. The latter is elongate (Fig. 7A),

the largest observed being 30 mm long. The oral siphon is wide with six large

petal-like lobes (Fig. 7B). The cloacal siphon is anterior, in a short tube whose

dorsal part is elongated as a long and simple languet, rarely with basal teeth

SOUTH AFRICAN ASCIDIANS 7

Fig. 7. Aplidium flavolineatum. A. Zooid. B. Details of the thorax and abdomen.

C. Abdomen and ovary. D. Larva.

(Fig. 7B). Six long tentacles alternate with six smaller ones and a dozen buttons,

located on a ring situated very high in the oral siphon. The thoracic muscles are

essentially longitudinal with thin, regularly spaced fibres.

All tissues of many colonies contain dark, round pigment cells that may be

dense or scarce, accumulated mostly in the thoracic body wall and branchial

sinuses. The branchial sac has 10-12 rows of 12-15 stigmata, depending on

zooid size (Fig. 7B). The dorsal line is not perforated and the dorsal languets

are displaced to the left side in the posterior part of the thorax. The abdomen is

approximately as long as the thorax. The oesophagus is long. The stomach is

shorter dorsally than ventrally. Its wall has about 30 folds, some of them

8 ANNALS OF THE SOUTH AFRICAN MUSEUM

interrupted and oblique (Fig. 7B). The post-stomach is annular, followed by an

oval mid-intestine. The rectum begins with caeca at the bottom of the gut loop

(Fig. 7C) and remains isodiametric when empty until its aperture. The anus has

two lobes.

The post-abdomen is extremely long. The ovary is far from the gut and at

some distance from the testis (Fig. 7C). The double row of testicular vesicles

occupies at least half the length of the post-abdomen, and reaches the heart. In a

large zooid we counted more than 100 testicular vesicles (Fig. 7A).

Two or three embryos were maturing in the cloacal cavity, which is

distended at their level, but the body wall does not protrude in a pouch. The

larvae (Fig. 7D) have an oval trunk 0.5 mm long, an otolith and an ocellus. The

three adhesive papillae are distally flattened into discs and have thin, long

stems. They alternate with four long digitiform ampullae. There are two pairs of

digitiform ampullae on each side of the median adhesive papillae. In addition,

there are numerous dorsal and ventral round vesicles (Fig. 7D). The tail is

coiled in a three-quarter turn.

Remarks and distribution

Aplidium flavolineatum differs from A. circulatum in colony shape, in having

more numerous stomach folds, and in larval structure. Nevertheless, the

uncertainty of several authors regarding the two species can be easily

understood, as the colonies are variable. The synonymy with Amaroucium

erythraeum after Michaelsen (1921) needs to be verified. The Chesterfield

Islands (New Caledonia) specimens previously identified as A. flavolineatum

by F. Monniot (1987) are very similar, but differ in having a protruding

brood pouch. Kott (1992) re-identified the material as different species

(A. multilineatum, A. multiplicatum, A. gastrolineatum, and A. robustum)

specimens she had previously attributed to A. flavolineatum. Consequently, the

known geographical distribution of A. flavolineatum remains limited to South

Africa, from Saldanha Bay to Sodwana Bay. It is common intertidally along the

whole south coast.

Aplidium haesitans F. Monniot sp. nov.

Fig. 8

Material

Holotype. SAM-A25842, Isipingo, KwaZulu-Natal (30°00’S 30°57’E), in

rock pool, collected by C. L. Griffiths, 19 July 1994.

Description

A single colony 5 mm across, covered with sand, was attached to the

underside of a colony of Didemnum granulatum. The soft tunic is glassy,

perfectly transparent and does not contain sand. There is a common central

cloacal aperture, but oral openings are not evident. The zooids are parallel with

orange-red thoraces in formalin, fading progressively.

SOUTH AFRICAN ASCIDIANS 9

Fig. 8. Aplidium haesitans sp. nov. A. Entire zooid. B. Other side of the abdomen.

C. Brooding zooid. D. Detail of the siphons. F. Anterior part of the branchial sac.

G. Larva.

The zooids are thin and long. The cylindrical oral siphon has eight sharp

lobes (Fig. 8D). The cloacal siphon is a narrow tube, its dorsal rim elongated as

a stout short languet with a pointed (Fig. 8A), bilobed (Fig. 8E), or trilobed

(Fig. 8D) tip. The longitudinal thoracic muscles are thin, number eight per side,

and are regularly spaced. Thirty-two oral tentacles of three sizes are crowded

against each other in a single ring. The branchial sac has 13 rows of stigmata in

the most mature zooids, but fewer in others. Several rows are cut by a

parastigmatic vessel (Fig. 8F) and some of them have divided stigmata. The

rows of stigmata are interrupted along the dorsal line (Fig. 8F). On the left side,

thin dorsal languets arise from the transverse vessels and smaller ones arise

from the parastigmatic vessels (Fig. 8F).

The gut loop is as long as the thorax. The stomach is cylindrical with five

longitudinal folds (Fig. 8B), followed by a narrow segment enlarged in a ring at

middle length. The mid-intestine is wide. The rectum begins with caeca at the

bottom of the gut loop. The anus opens far back in the thorax, at the third row

of stigmata, above the oesophageal entrance (Fig. 8A).

10 ANNALS OF THE SOUTH AFRICAN MUSEUM

The post-abdomen is longer in zooids with developed testis, shorter when

the ovary has large oocytes. The ovary is anterior, just behind the abdomen

(Fig. 8A), followed by a single row of testicular vesicles extending to the body

extremity.

Up to nine embryos are incubated in the peribranchial cavity (Fig. 8C). The

larval trunk measures 0.4 mm (Fig. 8G). Larvae possess an ocellus, an otolith

and three adhesive papillae on long peduncles, separated by two odd, long

conical ampullae. Numerous small round vesicles are accumulated dorsally and

ventrally.

Remarks

A single colony of such small size with few but mature zooids may be an

incompletely developed specimen. Nevertheless it contains many larvae, so the

zooids have probably attained their final morphology. We hesitated before

including this specimen in the genus Aplidium (thus the species name). Eight

oral lobes occur in several genera of Polyclinidae and have limited specific

diagnostic value. The cloacal siphon in a tube with a languet is also a character

common to some species of Aplidium, Ritterella and Synoicum; Synoicum has a

smooth-walled stomach. The difficulty is to decide, in so small a colony,

whether the common cloacal aperture is the opening of a true common cloacal

cavity or only a depression into which separate cloacal siphons open, as in some

Ritterella species. Parastigmatic vessels are more common in the genus

Ritterella than in Aplidium, but in the genus Aplidium the number of rows of

stigmata is generally higher. The larval structure could correspond to one or the

other genus.

The presence of eight oral lobes, 13 or more rows of stigmata with

parastigmatic vessels, five stomach folds, and a larva with two odd ampullae

between the three adhesive papillae excludes all already described species of

Aplidium or Ritterella. The presence of a small common cloacal aperture

persuades us finally to place this new species into the genus Aplidium.

Aplidium mernooensis (Brewin, 1956)

Figs 1B, 9

Amaroucium mernooensis Brewin, 1956: 132, fig. 4A.

Aplidium mernooensis: Millar, 1982: 22, fig. 8. Monniot, F., 1987: 528, fig. 11H, K.

Aplidium filiforme Kott, 1992: 542, fig. 75.

Material

Two colonies. Sodwana Bay, KwaZulu-Natal, 14-28 m (Schleyer coll.).

Description

The colonies are densely impregnated with sand and consist of lobed masses

of spherical outline. The zooids are located in circular systems around very

small central cloacal apertures. The zooid thoraces are red in life but yellow in

formalin; the abdomens are colourless in a colourless tunic. Some lobes of the

a e

SOUTH AFRICAN ASCIDIANS 11

Fig. 9. Aplidium mernooensis. A. Zooid. B. Thorax and abdomen of a brooding zooid.

C. Other side of the abdomen. D. Gonads. E. Larva.

colonies consist of only one system, but most often the lobes are grouped in

large common masses.

The zooids are thin and long (Fig. 9A). The oral siphon has eight small

lobes (Fig. 9B). The narrow cloacal siphon is prolonged by a trifid languet that

extends its upper rim (Fig. 9B). The longitudinal thoracic musculature is made

up of 7-8 muscles on each side, issuing from the oral siphon, and 4-6 muscles

12 ANNALS OF THE SOUTH AFRICAN MUSEUM

coming from the cloacal siphon. The branchial sac has five rows (Fig. 9B) of

12-13 stigmata on each side. The abdomen is narrower than the thorax. The

stomach wall has five deep folds (Fig. 9C), the mid-intestine is olive-shaped and

the rectum begins with caeca (Fig. 9B). The post-abdomen is long, even when it

does not contain gonads. The ovary is far from the gut, half way along the post-

abdomen. Few testicular vesicles occur in a single row before and behind the

ovary (Fig. 9D), but do not reach the cardiac extremity. |

Two to three larvae are incubated in the peribranchial cavity. They are

small with an average trunk length of 0.5 mm. They have three well-spaced

anterior adhesive papillae, between each of which is a branched protuberance of

bunched, small vesicles. Numerous small additional vesicles extend in an

anterior crescent on each side of the papillae (Fig. 9E). The median vesicles

between the papillae only appear at an advanced stage of the larva. They are

also present in the material from New Caledonia (Brewin 1956).

Remarks and distribution

All characteristics correspond well to the Brewin’s (1956) type specimen

from Chatham Rise, to the material described by Millar (1982) from New

Zealand, and to the specimens from New Caledonia (Monniot, F. 1987). The

only difference is that the present colony is more massive and most of the lobes

consist of several systems. |

The species Aplidium filiforme Kott, 1992, comprising specimens from

Western Australia and Queensland, perfectly corresponds to the South African

specimens, and only differs from the type in that the colony lobes are made of

several systems. We consider it a synonym.

Aplidium monile F. Monniot sp. nov.

Fig. 10

Material

Holotype. SAM-A25843, Thompson’s Pool, near Ballito (29°31’S

31°13’E), KwaZulu-Natal, collected by C. L. Griffiths, 11 July 1994.

Other material. Several specimens, Sodwana Bay, KwaZulu-Natal, intertidal

(Schleyer coll.).

Description

Several cushion-shaped colonies were collected, the largest being 30 mm in

diameter; they are of variable thickness, up to 10 mm. They are very soft and

pink with paler apertures arranged in irregular double rows, giving a botryllid

appearance. The common cloacal openings are simple holes. No sand is

embedded in the colony but some sediment is stuck to the sides and the basal

layer of the pads.

The zooids have a red thorax in life. In formalin, the colour fades

progressively, leaving only four red spots at the base of the oral siphon,

sometimes linked in pairs by a red line. The other tissues turn yellow and later

become colourless. The zooids are perpendicular to the colony surface. The six

oral lobes are large but the siphon itself is short (Fig. 10A). The cloacal opening

SOUTH AFRICAN ASCIDIANS 13

XK tally, » B

Fig. 10. Aplidium monile sp. nov. A. Thorax. B. Post-abdomen. C. Thorax and abdomen

of a brooding zooid. D. Larva.

faces the first row of stigmata. Its upper rim has a simple pointed languet

(Fig. 10A), sometimes with two small lateral lobes. The thoracic muscles are

mostly longitudinal with thin fibres. The branchial sac has 10-11 rows of

stigmata (Fig. 10A) that are not interrupted on the dorsal line.

The abdomen is about the same length as the thorax. The posterior side of

the stomach is half way along the gut loop. There are 18-20 longitudinal folds

in a transverse section, some of which are cut or interrupted (Fig. 1OA, C). The

post-stomach has the usual annular swelling (Fig. 10A). The olive-shaped mid-

intestine is separated from the rectal caeca by a constriction. The anus has two

lobes and is mid-way along the thorax. The pyloric duct enters the stomach in

the middle of its side. The post-abdomen may be very long. The ovary is far

14 ANNALS OF THE SOUTH AFRICAN MUSEUM

from the gut loop (Fig. 10B), and is followed by a double row of testis vesicles

that occupy the posterior half of the post-abdomen to the heart (Fig. 10B).

The larvae are brooded inside the peribranchial cavity, rather posteriorly

(Fig. 10C). They often protrude on the dorsal side of the thorax. We observed a

maximum of five in any zooid. The larvae (Fig. 10D) have a trunk 0.6 mm in

length. The tail encircles three-quarters of the trunk. The sensory vesicle is

located rather far back. The three adhesive papillae are short. A half ring of

round vesicles on each side of the anterior side is reminiscent of a pearl

necklace (Fig. 10D), giving this ascidian its specific name. There are no median

ampullae between the adhesive papillae.

Remarks

This species nearly fits the description given by Kott (1992) for what she

named Aplidium altarium (Sluiter, 1909). However, the type specimen from

Indonesia (ZMA TU 176) has conspicuously different larvae and a short post-

abdomen. Millar’s (1956) description of samples from Mozambique, identified

as A. altarium, corresponds better to the type of A. altarium with regard to the

larvae, but the post-abdomen is in a resting state and the colonies are very

small. The distance between these localities increases the doubt about the

species identification. ;

Aplidium monile sp. nov. has many characteristics in common with Aplidium

rosarium Kott, 1992, from Queensland; both are gelatinous colonies and the

zooids have 12 rows of stigmata and 20 stomach folds. The gonads of

A. rosarium are not described. Its larvae also have a half-ring of vesicles on

each side of the adhesive papillae, but differ in having median ampullae between

the papillae.

Aplidium monile differs from A. flavolineatum in the shape of the zooid

systems (which are not circular), the number of stomach folds and the larval

structure.

Aplidiopsis tubiferus F. Monniot sp. nov.

Figs 1C, 11A-C

Material

Holotype. MNHN A1 APL.A 16, Ibo Island, Mozambique, 10 m, collected

by Monniot, 1995.

Other material. One colony, Sodwana Bay, KwaZulu-Natal, 21 m (Schleyer

coll.).

Description

The colonies form balls, the largest collected being 25 mm in diameter,

supported by a wide cylindrical stalk 15 mm high. The colour is tan due to

sparse clear sand grains adhering to the colony surface mixed with the dark

purple colour of the tunic. The colonies turn orange in formalin. Sand is totally

absent inside the tunic, which has a tough surface layer, but soft internally

between the zooids.

SOUTH AFRICAN ASCIDIANS IV

‘oot. o

go 00 () 000) s oe

uu” (000000 :

gg ie :

0.25 mm 0.5 mm

Fig. 11. A-C. Aplidiopsis tubiferus sp. nov. A. Zooid. B-C. Siphons. D-H. Polyclinum

isipingense. D. Zooid. E. Siphons of another zooid. F. Details of the thorax and abdomen.

G. Branchial papillae. H. Larva.

16 ANNALS OF THE SOUTH AFRICAN MUSEUM

The zooids are perpendicular to the colony surface, and are arranged in

circles around common cloacal apertures. In formalin their colour is orange.

The oral siphon is short with six lobes (Fig. 11B, C). The cloacal siphon forms

a long tube (Fig. 11B, C) and the dorsal margin can be elongated into a short,

wide languet with teeth on the anterior edge (Fig. 11A). A papilla protrudes

dorsally below the cloacal siphon (Fig. 11A-C). The thoracic muscles are

oblique within the thin, transparent body wall (Fig. 11A). The oral tentacles

alternate in three orders of size. The branchial sac contains 12-13 rows of

14-18 stigmata on each side (Fig. 11A). An unperforated area is located on

each side of the endostyle. The rapheal languets are long and wide. There are

no papillae along the transverse vessels.

The abdomen is clearly shorter than the thorax and the spherical, smooth-

walled stomach is located in its middle (Fig. 11A). The gut loop is not twisted.

The post-abdomen is inflated by the gonads and the heart, and linked to the

abdomen by a long, thin, straight peduncle. No larvae were present in the

colonies from South Africa or Mozambique.

This species is characterized by its long, tubular cloacal siphon (from which

the specific name is derived) and the long, narrow, post-abdominal peduncle.

Remarks

The shape of the colony of A. tubiferus resembles the Tasmanian

A. confluata Kott, 1992, and the Southern Australian A. mammillata Kott, 1992.

However, these differ in having the cloacal languet inserted above the siphon,

more stigmata rows, and zooids arranged in double rows.

Aplidiopsis pyriformis (Herdman, 1886) from Kerguelen has a shorter post-

abdomen and more rows of stigmata.

Polyclinum isipingense Sluiter, 1898

Figs 1D, 11D-H

Polyclinum isipingense Sluiter, 1898a: 21, pl. 2 (fig. 1), pl. 4 (fig. 3). Millar, 1962: 136,

fig. 10, synonymy. Plante & Vasseur, 1966: 144, pl. 1 (fig. 4). Monniot & Monniot,

1976: 358.

Material

Several colonies. Isipingo, KwaZulu-Natal, rock pools (Griffiths coll.);

Saldanha Bay and Miller’s Point, False Bay, low tide (Monniot coll.).

Description

The colonies form large cushions, the largest collected being 50 mm in

diameter. They are covered with sand but there are far fewer particles inside the

tunic. The colour is dark green or brown. The common cloacal apertures are

raised in short chimneys above the colony surface. The zooids are arranged in

circular systems. The tunic is transparent and soft but resistant.

The six oral lobes are pointed. The cloacal siphon has a long languet ending

in a sharp thin tip or several teeth on a straight margin (Fig. 11D, F). There is a

small papilla on the dorsal body wall behind the cloacal siphon (Fig. 11D, F).

SOUTH AFRICAN ASCIDIANS 7

The muscles are restricted to the anterior part of the thoracic wall (Fig. 11D).

The branchial sac (Fig. 11F) contains 11-15 stigmata rows, a number which

varies with zooid and colony growth. The papillae on the transverse vessels are

about as numerous as the stigmata (Fig. 11G). The abdomen has the usual shape

in the genus. The post-abdomen hangs on a long thin peduncle (Fig. 11D). The

ovary lies in the centre of a cluster of testis vesicles. The larvae are incubated

within the oviduct in the cloacal cavity (Fig. 11F). The trunk is 0.5 mm long

(Fig. 11H). The three adhesive papillae are separated by two vesicles, and four

ampullae are present on each side. There are also a dorsal and ventral series of

vesicles. One or several calcium oxalate crystals are found in the visceral mass.

Remarks and distribution

The species is well characterized by the shape of the colony and the raised

common cloacal apertures above circular systems of zooids. Its known

distribution extends from Madagascar (Plante & Vasseur 1966) and

Mozambique (Monniot & Monniot 1976) to the Western Cape Province. It

differs from P. neptunium Hartmeyer, 1912, in its larval structure.

Pseudodistoma africanum Millar, 1954

Figs 1E, 12A-D

Pseudodistoma africanum Millar, 1954: 128, fig. 1; 1962: 138, fig. 12.

Material

Several colonies. Sodwana Bay, KwaZulu-Natal, 24-34.5 m (Schleyer

coll.).

Description

All colonies are equivalent in shape, and correspond to that of the type

specimen in the British Museum. They consist of one to several stalked lobes,

each with a sandy peduncle and a wider conical head containing the thoracic and

abdominal parts of the zooids. The tunic around the siphons has no sand but

some particles are embedded deeper between the zooids. The colour of the

colonies varies from white (rarely) or pink to a deep orange-red. The colour is

partly due to the tunic, but mostly to the zooids in which the thoraces are deeply

pigmented. In formalin the pigment becomes yellow and later disappears.

The zooids (Fig. 12A) are immature in all colonies. The thorax is short

(Fig. 12B). The siphons are also short and have six lobes. There are at least

30 stigmata per half row. The gut forms a simple loop. The stomach, at the

mid-length of the abdomen, is square in cross section, giving it longitudinal

crests when contracted. The base of the rectum is enlarged. The post-abdomen

is extremely long. The gonads were not developed, and no larvae were found.

Remarks and distribution

In spite of the absence of gonads and larvae, the colonies and zooids were

characteristic enough to identify the species by comparison with the Millar

18 ANNALS OF THE SOUTH AFRICAN MUSEUM

cotypes from the British Museum. The distribution of P. africanum is presently

restricted to South Africa.

Pseudodistoma delicatum F. Monniot sp. nov.

Figs 1F, 12E-G

Material

Holotype. SAM-A25844, Sodwana Bay (27°33’S 32°42’E), KwaZulu-

Natal, 24 m; collected by M. Schleyer, 8 November 1994.

Other material. Several colonies from Sodwana Bay (Schleyer coll.).

Description

The colonies form a soft encrustation on polychaete tubes which are over

100 mm in length. They are folded back on themselves when they extend

beyond the support of the tubes. The colony thickness varies from 5 to 10 mm

when fixed. In life, the colour is bright orange with transparent red siphons

slightly raised above the surface. The colour disappears when fixed, and the

tunic becomes perfectly transparent. There is no embedded sand. The zooids are

arranged in sinuous lines, with their siphons placed one behind the other. The

general consistency is soft, but the tunic is resistant.

The short zooids (Fig. 12E, F) are only 5-6 mm in length when partially

contracted. Both siphons are short and have six round lobes. There is a pigment

spot on the neural ganglion. The tentacles are numerous and short, in three

orders of size in three circles at the base of the oral siphon. There is a large

unperforated area before the branchial sac. The first row of stigmata is dorsally

curved (Fig. 12F) with 22-24 perforations on each side. The waist between the

thorax and abdomen is circled by a belt of pigmented tunic. The abdomen is

short, with a smooth-walled stomach in the middle (Fig. 12F). The rectum

begins with the usual caeca (Fig. 12E, F).

The post-abdomen length depends on the gonad development. It is generally

short and may be much reduced when the testis vesicles regress and the ovary

develops. In the male phase, there is a cluster of about 25 round testis vesicles

that does not reach the heart. When the ovary develops, it grows close to the gut

and against the testis, so that the male vesicles gather in the anterior part of the

post-abdomen, swelling it and giving the post-abdomen a triangular shape

(Fig. 12E, F). The post-abdomen terminates in several vascular appendages

(Fig. 12E, F).

The larvae (Fig. 12G) measure 0.75 mm in length in trunk, with a tail in

three-quarters of a turn around it. They are incubated, one at a time, in an

extremely distended dilation of the thoracic body wall which has no peduncle

(Fig. 12E, F). In mature larvae three rows of stigmata are open (Fig. 12G). The

ocellus and the otolith are present. The three anterior papillae are very wide,

forming large cups that are crowded together to form a compact mass separated

from the visceral mass by a constriction. No vesicles or ampullae were

observed.

SOUTH AFRICAN ASCIDIANS 0

Remarks

This species is clearly distinct from P. africanum by the colony shape and

consistency, the absence of embedded sediment, and the shorter post-abdomen.

Pseudodistoma delicatum differs from P. fragile Tokioka, 1958, in the

colour of the colonies, the less brittle consistency of the tunic, and, mostly, in

the size and anatomy of the larvae.

Ritterella solida F. Monniot sp. nov.

Figs 1G, 13A, B

Material

Holotype. SAM-A25845, Oudekraal, Cape Peninsula (33°59’S 18°21’E),

10 m; collected by C. L. Griffiths, 18 August 1994.

Etymology

The specific name refers to the particularly solid and massive colony.

Description

The large, ridged and folded colony is white in life, 45 mm thick, tough,

impregnated with sediment but with little sand at the surface. The zooid

apertures do not manifest any regular arrangement. When fixed, the colony

turns brown.

The zooids are slender (Fig. 13A) and perpendicular to the colony surface.

Both siphons are closely spaced, cylindrical and of equal size with six sharp

lobes (Fig. 13B). The siphons are orange in life. The cloacal siphon is closed by

a velum. There are 16 tentacles in three orders of size. The thoracic

musculature is weak. The branchial sac (Fig. 13B) has nine rows of stigmata

with an average of 14-15 stigmata on each side. There are no parastigmatic

vessels nor are there papillae on the transverse vessels.

The abdomen is slightly shorter than the thorax. The stomach is as wide as

it is long and has five deep longitudinal folds (Fig. 13B). The gut loop is very

narrow. The rectum begins with two caeca at some distance from the bottom of

the loop. The anus opens in the middle of the thorax through two large lobes.

The post-abdomen is long (Fig. 13A). The gonads are poorly developed in

the single colony studied. The ovary is far behind the abdomen (Fig. 13A). The

testis vesicles are in two rows and occupy the second half of the abdomen but

do not reach the heart at this stage.

The colony does not contain embryos or larvae.

Remarks

Of the species of the genus Ritterella that have about ten rows of stigmata,

many have colonies made of pedunculate lobes: R. cornuta Kott, 1992;

R. multistigma Kott, 1992; R. pulchra (Ritter, 1901); and R. tokiokai Kott,

1992. Among the massive colonies only two deep-sea species have stigmata

rows approaching these in number: R. mirifica Monniot, C. & Monniot, F.,

1983, and R. rete Monniot, C. & Monniot F., 1991. They are very different

from Ritterella solida sp. nov.

20 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 12. A-D. Pseudodistoma africanum. A. Zooid. B. Detail of the thorax. C. Thorax

and abdomen of another zooid. D. Abdomen of a zooid from the type colony.

E-G. Pseudodistoma delicatum sp. nov. E-F. Two zooids. G. Larva.

Euherdmania divida F. Monniot sp. nov.

Figs 1H, 13C-E

Material

Holotype. SAM-A25846, Isipingo, KwaZulu-Natal (30°00’S 30°57’E), in

rock pools; collected by C. L. Griffiths, 10 July 1994.

SOUTH AFRICAN ASCIDIANS 21

Fig. 13. A-B. Ritterella solida sp. nov. A. Zooid. B. Detail of the thorax and abdomen.

C-E. Euherdmania divida sp. nov. C. Zooid. D. Thorax. E. Abdomen and ovary.

Description

Minute, elongate, stalked zooids, each coated with sand, are joined at their

base into the colony. Each zooid is 20 mm long, and 2 mm in diameter at the

enlarged distal end. Each cylindrical siphon has six pointed lobes (Fig. 13D).

The oral siphon is oriented toward the ventral side. The number of tentacles is

variable, most often 16 in three orders of size.

22 ANNALS OF THE SOUTH AFRICAN MUSEUM

The thoracic musculature is weak in a network of thin transverse and longi-

tudinal fibres, but circular muscles make sphincters around the siphons. The

longitudinal thoracic fibres extend over the abdomen and post-abdomen. The

branchial sac and endostyle form a posterior horn at the base of the thorax

(Fig. 13D).

The branchial sac (Fig. 13D) has 6-7 rows of elongated stigmata, generally

with 32 stigmata in the first half row and 20 in the last half row. The first and

the last rows have a complete or partial parastigmatic vessel (Fig. 13D). The

transverse vessels are low with dorsally 5-6 languets. There are no languets at

the level of the parastigmatic vessels. Some stigmata rows occasionally have

incomplete parastigmatic vessels. The abdomen is about the same length as the

thorax. The oesophagus is short, as long as the stomach. The stomach wall is

irregularly folded (Fig. 13E) and 10-12 folds can be counted in transverse

sections. The typhlosole is conspicuous. The intestine is thin beyond an annular

swelling (Fig. 13E). A constriction before the rectal caeca marks the bottom of

the gut loop. The bilobed anus opens at the level of the second to last row of

stigmata.

The post-abdomen is very long (Fig. 13C), longer than the thorax plus

abdomen.

The ovary, located at some distance from the gut loop, is immediately

followed by a line of testicular vesicles that are limited to the anterior half of the

post-abdomen (Fig. 13C). No larvae were present in the colonies studied.

Remarks

The genus Euherdmania contains few species but is widely distributed in the

world. Some of them have massive colonies with zooids grouped in a common

tunic. They are E. gigantea (Van Name, 1921) in the western Atlantic Ocean,

E. morgani Millar & Goodbody, 1974, from Jamaica, E. rodei Pérés, 1949,

from Senegal and E. solida, Millar, 1953, from the Gold Coast, in which only

the thoraces are isolated. Among the species with separated zooids, many have

numerous rows of stigmata, as in E. areolata Millar, 1978, from Guyana which

has an areolated stomach, E. claviformis (Ritter, 1903) from California,

E. digitata Millar, 1963, from the western Pacific, E. fasciculata Monniot, F.,

1983, from Guadeloupe, and E. translucida Kott, 1992, from southern

Australia.

The nearest species to E. divida is E. dumosa Monniot, F., 1987, from New

Caledonia. It has the same colony structure with embedded sand. However,

E. dumosa has only four rows of stigmata cut by parastigmatic «vessels, seven

rapheal languets, and a very different stomach in which the wall is slightly

spotted. The thoracic muscles and the gonad disposition are similar in both

species.

Family Polycitoridae

Eudistoma bituminis F. Monniot sp. nov.

Fig. 14A-C

SOUTH AFRICAN ASCIDIANS 23

Material

Holotype. SAM-A25847, Sodwana Bay, KwaZulu-Natal (27°33’S

32°42’E), intertidal pools, collected by M. Schleyer, Nov. 1994.

Other material. Several colonies, Sodwana Bay, KwaZulu-Natal, intertidal

pools (Schleyer coll.); Mayotte, Comoros islands (Gaydou coll.).

Description

The colonies are about 10 mm thick, large, dark pads. They are several

centimetres across, tough, encrusted with sand, and resemble bitumen (hence

Fig. 14. A-C. Eudistoma bituminis sp. nov. A-B. Zooids. C. Larva. D-E. Eudistoma

caeruleum. D. Zooid from South Africa. E. Zooid from Madagascar.

24 ANNALS OF THE SOUTH AFRICAN MUSEUM

the species name). The zooid apertures are arranged in circular systems, with

the oral and cloacal lobes slightly protruding above the smooth colony surface.

The tunic is black in the upper part, slightly more translucent deeper. It contains

embedded sand that is more abundant in the interior than at the colony surface.

The tunic contains abundant brown pigment cells.

The zooids (Fig. 14A, B) are contracted and light brown in formalin. Both

siphons have six sharp lobes. The longitudinal muscles are very strong and

extend in two ribbons along the abdomen, making horns at the body extremity.

The tentacles are very numerous in a single ring. There is no unperforated

space anterior to the branchial sac. The stigmata are very elongated, about

15 per half row. The abdomen is much longer than the thorax. The stomach is

as long as it is wide and is followed by a narrow cylindrical section (Fig. 14B).

The mid-intestine is wide and short, sometimes as wide as the stomach. The

rectum, without caeca, begins after a constriction in the descending limb of the

gut loop (Fig. 14B).

The gonads are located within the gut loop, behind the stomach, and consist

of a few round testicular vesicles (Fig. 14A, B) and an ovary with several

oocytes varying in size. Two or more long vascular processes arise from the

centre of the gut loop.

The larvae (Fig. 14C) are incubated in the peribranchial cavity. They have a

light brown, elongated trunk 0.8 mm in length and half encircled by the tail.

The three adhesive papillae have stout, long, brown stems. They are separated

by two double, long, median ampullae. On each side are several long ampullae

with shorter ones at their base (Fig. 14C). The number of these lateral ampul-

lae seems a little variable, as well as their shape, but they are always numerous.

The ocellus and otolith are present between the embryonic siphons. The

branchial sac is not yet differentiated when the adhesive ampullae begin to evert.

Remarks

This Eudistoma species is different from other known African species. It

differs from E. atrum Monniot, F. & Monniot, C., 1997, from Tanzania and

Djibouti, which has a black but mucous-covered and naked colony with notably

different larvae.

The enlarged mid-intestine and the brown base of the larval adhesive

papillae in E. bituminis resemble those in the western Pacific species E. reginum

Kott, 1990, but the latter has different larval anterior ampullae, colonies devoid

of sand and an asymmetrical stomach.

Although only collected in Sodwana Bay and Mayotte, Comoros islands,

this species probably has a wider distribution in the Indian Ocean.

Eudistoma caeruleum (Sluiter, 1898a)

Fig. 14D, E

Distoma caeruleum Sluiter, 1898a: 14, pl. 2 (fig. 4), pl. 4 (fig. 11).

Polycitor (Eudistoma) caeruleum: Hartmeyer, 1909: 1431.

Polycitor (Eudistoma) caeruleus: Michaelsen, 1919: 73.

SOUTH AFRICAN ASCIDIANS 2

Sigillina (Eudistoma) caerulea: Michaelsen, 1934: 141.

Eudistoma caeruleum: Millar, 1956: 919, fig. 6; 1962: 157, fig. 21; 1964: 163. Plante &

Vasseur, 1966: 147, pl. 3 (figs 17-19). Lafargue & Vasseur, 1989: 61.

Material

Several specimens. Sodwana Bay, KwaZulu-Natal, intertidal pools (Schleyer

coll.); Thompson’s Pool, near Ballito, KwaZulu-Natal (Griffiths coll.); Nosy

Bé, Madagascar, 15 m (Laboute coll.).

Description

The colonies are club-shaped and dark blue in colour. Several lobes may

arise from a common base. The heads are naked but some epibionts are fixed on

the peduncle. The zooids, restricted to the head, do not form systems. They are

regularly spaced with the cloacal siphon above the oral siphon. The tunic in the

head region is a translucent blue. Dark pigment cells are accumulated around

the zooids.

The zooids are a dark or lighter blue, with the siphons darker than the

remainder of the body wall. Both siphons are short with six round lobes. The

longitudinal and transverse thoracic muscles are regularly spaced in a well-

developed network, and longitudinal bundles extend along the abdomen. The

oral tentacles are thick in two orders of size, in two circles. The urn-shaped

dorsal tubercle protrudes.

The first row of stigmata curves dorsally. In a relaxed zooid, we counted on

the right side 35 long stigmata in the first row and 28 stigmata in the two last

rows. They are less numerous on the left side. The unperforated areas anterior

and posterior to the branchial sac are very narrow (Fig. 14E). The abdomen is a

least three times as long as the thorax in relaxed zooids (Fig. 14E). The stomach

is asymmetrical at the posterior extremity of the abdomen and the post-stomach

and mid-intestine are especially short; the rectum with caeca begins with

widening at the bottom of the gut loop. The gonads consist of a cluster of round

testis vesicles and a central ovary contained in the gut loop behind the stomach

(Fig. 14D, E). The abdomen is prolonged by a thin and very long vascular

process, devoid of muscles.

The larvae are brooded in the peribranchial cavity, which contains up to five

embryos. The most mature larvae that we found have an ocellus, an otolith,

three anterior adhesive papillae but no other differentiation. The tail encircles

the trunk, which is 0.5 mm in length.

Remarks and distribution

The colonies and zooids exactly correspond to the type specimen, which has

been re-examined. The geographic distribution of this spectacular species

extends from KwaZulu-Natal in South Africa to Mozambique, the west coast of

Madagascar, and Mayotte (Comoros islands).

Eudistoma hospitale F. Monniot, 1998

Eudistoma hospitale Monniot, F., 1998: 430, figs 1-2. Monniot, F. & Monniot, C., 1999:

19, fig. 13A-C, pl. 2F.

26 ANNALS OF THE SOUTH AFRICAN MUSEUM

Material

Several colonies. Sodwana Bay, KwaZulu-Natal, 19 m (Schleyer coll.).

Gouritz River mouth (Griffiths coll.). Port Elizabeth, intertidal (Monniot coll.).

Description

In South Africa, this ascidian is a fleshy cushion, black at the surface and

grey and soft in the interior, with superficial sticky mucus and threads emerging

from the siphons. One colony from the southern Cape coast had bright blue

specks overlaid on a dark undertone at the colony surface. The colonies are

always thick pads with a flat surface or with low swellings. The zooids are

arranged in circular systems that are sometimes inconspicuous.

Remarks and distribution

This recently described material has the same structure in all locations and

the same filiform symbionts of unknown taxonomic status (Monniot, F. 1998).

This species has a wide geographic distribution, from the south-western

Pacific to South Africa and Tanzania, and it also occurs in a wide depth range

from low tide down to 30 m. .

Eudistoma illotum (Sluiter, 1898)

Fig. il, 15A-C

Distoma illotum Sluiter, 1898: 16, pl. 1 (fig. 3), pl. 3 (fig. 7).

Polycitor illotus: Hartmeyer, 1912: 303, pl. 38 (fig. 2), pl. 43 (fig. 5).

Sigillina (Hyperiodistoma) illota: Michaelsen, 1930: 491; 1934: 139.

Eudistoma illotum: Millar, 1955: 181, fig. 12; 1962: 160, fig. 24; 1964: 162, fig. 2.

non Eudistoma illotum: Rho, 1971: 110. Rho & Huh, 1984: 106. Rho & Lee, 1989: 65.

Material

Several colonies. Saldanha Bay; Kommetjie; Miller’s Point, False Bay;

under overhangs intertidally or in pools (Griffiths and Monniot coll.).

Description

The colonies are brown or purple encrusting cushions. The largest specimen

in this collection is 90 mm across and 20 mm thick. Paler zooids are visible

through a semi-transparent tough tunic. The siphons are not arranged in

systems. The tunic contains some faecal pellets and green, spherical inclusions,

but no sand. :

The zooids are not densely packed. Their siphons are short, equal in size,

with six round lobes. The most relaxed zooids reach 10 mm in length but have a

thorax only | mm long (Fig. 15A). The thoracic musculature consists of a

regular network of longitudinal and transverse fibers of equal thickness. The

longitudinal muscles extend in bundles along the abdomen. The oral tentacles

are numerous, in three orders of size, on three circles. There are unperforated

areas anterior and posterior to the branchial sac. In large zooids, the first row of

stigmata curves dorsally and contains 20 stigmata on the right side.

SOUTH AFRICAN ASCIDIANS 75)

The gut forms a long loop and the two limbs are thin and parallel

(Fig. 15A). The stomach is laterally flattened with a round outline and the

oesophagus enters it dorsally. A longitudinal crest often raises its side near the

typhlosole (Fig. 15A) but may have been caused by contraction. The conical

post-stomach and ovoid mid-intestine are separated by constrictions. The rectum

begins at an expansion of the bottom of the gut loop. The pyloric gland covers a

long segment of the rectum with a network of curled tubules.

The heart is not situated inside the gut loop but behind it, in the lower part

of the abdomen where the muscles are anchored. Several vascular processes of

varied lengths arise on the side of the gut loop.

The gonads, made of a cluster of testis vesicles and a central ovary, lie

behind the stomach, inside the gut loop (Fig. 15B). One to five larvae are

brooded in the peribranchial cavity. They distend the thoracic body wall and

protrude when mature and numerous.

The fully developed larvae (Fig. 15C) have a trunk 1 mm long and three

large adhesive papillae on stout stems. Between each of them are two dorso-

ventrally flattened vesicles. There are also one dorsal and one ventral vesicle of

variable shape. A flat ampulla covers the base of the most dorsal adhesive

papilla on each side of the larva.

Remarks and distribution

All the above characteristics correspond well with Hartmeyer’s (1912) and

Millar’s (1962) descriptions of E. illotum from the same geographic area. It is

not possible to retain as synonyms the Korean specimens identified as

E. illotum, by Rho (1971) and Rho & Huh (1984) as their descriptions are of a

different species.

Eudistoma illotum differs from other species in the Indian Ocean in its larval

structure and in the posterior location of its heart behind the gut loop. Its

geographic distribution is presently limited to the Western Cape Province, South

Africa.

Eudistoma modestum (Sluiter, 1898)

Fig. 1SD-H

Distoma modestum Sluiter, 1898a: 18.

Eudistoma modestum: Millar, 1962: 158, fig. 22.

Material

Several colonies. Isipingo, KwaZulu-Natal, intertidal (Griffiths coll.);

Sodwana Bay, KwaZulu-Natal, intertidal (Schleyer coll.).

Description

The colonies were found on vertical rock faces, which were exposed at low

tide. They are pale pink ‘buttons’, each colony consisting of several erect, club-

shaped heads above an encrusting base embedded with sand. The largest lobe is

10 mm in diameter. The zooids can be seen through a glassy tunic, free of

foreign matter.

28 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 15. A-C. Eudistoma illotum. A. Zooid. B. Gonads. C. Larva. D-H. Eudistoma

modestum. D. Zooid. E-F. Both sides of an abdomen. G. Pyloric gland. H. Larva.

The zooids are rather small (Fig. 15D), 5 mm long when relaxed. The

thorax represents 25-35 per cent of the total length of the zooid. The siphons

are short with six lobes. The thoracic musculature is weak. On the right side

SOUTH AFRICAN ASCIDIANS 29

there are about 18 stigmata in the first row and 15 stigmata in the second and

third rows. The stomach is asymmetrical with a smooth wall (Fig. 15E). It is

followed by a long post-stomach and a short mid-intestine. The rectum begins

with caeca at the pole of the gut loop (Fig. 15F); it remains straight and parallel

with the oesophagus. A pyloric gland of undulating, densely packed parallel

tubules (Fig. 15G) covers the rectal wall facing the stomach and more

anteriorly. The pyloric duct enters the posterior side of the stomach (Fig. 15G).

The gonads lie in the gut loop. The ovary is central within a group of a few

testis vesicles (Fig. 15E, F).

One or two larvae are incubated in the peribranchial cavity. The trunk,

three-quarters of which is encircled by the tail, is up to 0.5 mm long. The three

adhesive papillae are wide, alternating with three odd ampullae (Fig. 15H). The

ocellus and the otolith are present.

Remarks and distribution

At Isipingo, some specimens of Molgula scutata had settled between the

lobes of E. modestum.

This species differs from the smallest colonies of E. illotum in its paler

colour, the shape of the gut loop and the larvae. It has only been found in South

Africa.

Eudistoma occultum F. Monniot sp. nov.

Fig. 16A-D

Material

Holotype. SAM-A25848, Sea Point, Cape Town (33°55’S 18°23’E),

intertidal, collected by C. and F. Monniot.

Other material. Several colonies, locality data as for holotype.

Description

Numerous colonies were collected at low tide. They are barely visible in the

field (hence the species name), being colourless or pale pink, lobate colonies

with a gelatinous surface on a base encrusted with sand and all kinds of foreign

matter. The colonies are 20 mm in diameter and consist of several irregular

lobes no more than 3 mm thick when fixed. No sand is embedded in their

interior.

The zooids (Fig. 16A) are haphazardly intermingled inside the mucous

tunic. Most of them are strongly retracted and very short, the most relaxed

individuals being 7 mm in length. Both siphons are short with six lobes

(Fig. 16A). About 20 longitudinal muscles are regularly spaced on each side of

the thorax. There are numerous tentacles in three orders of size. The

unperforated areas anterior and posterior to the three rows of stigmata are

narrow. Twenty stigmata were counted in the first and third rows but only 15 in

the second row.

The abdomen occupies 80 per cent of the body length in relaxed zooids

(Fig. 16A). The stomach has a smooth wall, followed by a conical post-stomach

30 ANNALS OF THE SOUTH AFRICAN MUSEUM

0.3 mm

Fig. 16. A-C. Eudistoma occultum sp. nov. A. Zooid. B-C. Gut loop of two different

zooids. D. Larva. E. Tetrazona porrecta. E. Zooid.

and a short mid-intestine well separated by constrictions. The rectum begins at

the bottom of the gut loop and parallels the straight oesophagus (Fig. 16A). The

gonads (Fig. 16B, C) and the heart are located in the gut loop, behind the

stomach. There are one or several short post-abdominal vascular processes

(Fig. 16A-C). Five or six embryos are brooded in the distended peribranchial

cavity.

Mature larvae (Fig. 16D) are round, the trunk being 0.5 mm long. The

three adhesive papillae are short and thick, alternating with four odd ampullae.

SOUTH AFRICAN ASCIDIANS 31

There is a flat round vesicle on each side of the dorsal adhesive papilla. A

crescent of numerous filiform ampullae lies at the base of the papillae on each

anterior side. The larval branchial sac is already pierced with elongated first and

third rows of stigmata when the second row remains incomplete (Fig. 16D).

The ocellus and otolith are present.

Remarks

This very modest species differs from all other Eudistoma species in the

Indian Ocean in its small, lobed colonies and the structure of the larva. The

second row of stigmata being shorter than the first and third ones is also

distinctive.

Polycitor africanus Monniot & Monniot, 1999

Fig. 2A

Polycitor africanus Monniot, F. & Monniot, C., 1999: 22, fig. 13, pl. 3A.

Material

Two colonies, Durban, outer anchorage (Schleyer coll.).

Remarks and distribution

This species is common along the East African coast at shallow depth. It has

been collected at Pemba Island (Tanzania), Ibo Island (Mozambique), Nosy Bé

(Madagascar) and Durban (KwaZulu-Natal). The present colonies are not

sexually mature.

Tetrazona porrecta Millar, 1962

Fig. 16E

Tetrazona porrecta Millar, 1962: 146, fig. 15.

Material

Two colonies, Oudekraal, Cape Peninsula, 8 m and 9 m (Griffiths coll.).

Description

The colonies are encrusted with sand and form white small pads or crusts,

irregular in outline and 10-20 mm in diameter. The tunic is tough. Both siphons

of the zooids open at the colony surface with no arrangement into systems. The

cylindrical siphons are spaced well-apart at the same level and have six short

lobes (Fig. 16E). The oral tentacles are distributed in three circles. The

branchial sac has 16-18 stigmata on each side in the first of the four rows.

The abdomen is narrower than the thorax and most often folded under it.

The stomach is located midway down the gut loop and its wall has six

longitudinal folds. In these specimens only male gonads are present at the

bottom of the gut loop, with the testis vesicles compacted together in a tight

32 ANNALS OF THE SOUTH AFRICAN MUSEUM

mass. The heart lies behind the gut loop. Some vascular processes prolong the

abdomen.

Remarks and distribution

The newly collected specimens correspond well to Millar’s (1962) descrip-

tion. The species is common on the fronds of the red alga, Epymenia; it has

only been recorded from South Africa.

The only other species of Tetrazona is the Antarctic T. glareosa (Sluiter,

1906), which is very different, being closer to the Holozoinae, and containing

spicules (Monniot, C. & Monniot, F. 1983: 37, fig. 6E-G).

Cystodytes dellechiajei (Della Valle, 1877)

Figs 2B, 17

Distoma dellechiajei Della Valle, 1877: 40.

Material

Several colonies. Woolley’s Pool, False Bay, intertidal; Isipingo and

Sodwana Bay, KwaZulu-Natal, 15-20 m (Griffiths, Schleyer and Monniot coll.).

Description

The colonies look remarkably different depending on their size, stage of

zooid development and the abundance of spicules. Some of the pink colonies

from False Bay, which are at least 100 mm across and 10 mm thick, have

densely distributed disc-shaped spicules around the zooids and elsewhere

throughout the tunic mass. Others lack any well-formed spicules, having only

irregular crystals in some places. When abundant, the disc-shaped spicules,

which have a smooth thin edge and a maximum diameter of 250 um,

encapsulate the zooids. Smaller discs are crowded throughout the semi-opaque

or transparent tunic. The spicule density varies from place to place within the

same colony.

All of the colonies have zooids grouped into systems with 4-10 oral

apertures in a ring and the cloacal apertures juxtaposed in the centre of each

system. The colony surface is flat. Pigment cells are sometimes numerous

throughout the tunic thickness, and sometimes restricted to a thin layer around

the calcareous capsules. The zooids are not pigmented.

The less contracted zooids (Fig. 17A) are 5 mm long and perpendicular to

the colony surface. They are generally partially or fully retracted into the

spicule capsules if these are present. Both siphons have six round lobes. The

oral tentacles in 3-4 orders of size regularly alternate along a single ring.

The thin thoracic muscles are mostly longitudinal and regularly spaced, they

converge in two ribbons along the abdomen. Unperforated areas extend in front

of and beneath the branchial sac (Fig. 17A). The four rows of stigmata are

separated by high transverse membranes. The first stigmata row, with about

20 perforations on each side, is curved dorsally. In the most relaxed zooids the

waist is long and the body wall forms an asymmetrical fold on its side

(Fig. 17A), which is sometimes large but in others hardly visible.

SOUTH AFRICAN ASCIDIANS 33

Fig. 17. Cystodytes dellechiajei. A. Zooid. B. Gonads. C. Larva.

The gut loop is not twisted. It is divided into a narrow oesophagus, a wide

smooth-walled stomach, a narrow post-stomach and a wide rectum beginning in

the descending limb of the gut loop (Fig. 17B). When mature, the testis has

many lobes in a cluster (Fig. 17B). The ovary begins to develop against the

testis lobes, which disappear as the oocytes reach a large size and protrude

outside the abdomen. The eggs remain in the oviduct in a pouch of the body

wali hanging from the waist.

The larvae (Fig. 17C) have a trunk 1 mm long, the tail being coiled in about

half a turn around it. The ocellus and the otolith are present and four rows of

stigmata are already differentiated. The three adhesive papillae are linearly

arranged in the centre of terminally fused ampullae supported by their bases as

four pillars on each side.

Two or three vascular processes of variable length are sometimes present on

the side of the abdomen.

34 ANNALS OF THE SOUTH AFRICAN MUSEUM

Remarks and distribution

Except for European collections, we do not accept previous identifications

from distant geographic areas without seeing well-preserved and mature

colonies. Thus, no further synonymy is given here.

Variability in C. dellechiajei at the same station and even within a same

large colony is surprising. We have tentatively, but unsuccessfully, tried to find

significant differences allowing us to describe geographically separate species.

The tunic is transparent or opaque and the colour in life varies from white to

pink and purple. The spicules may be abundant, well-formed or absent, with all

possible intermediates. The anatomy of the zooids is very difficult to compare as

they are never totally relaxed. The number of testis lobes increases during

growth; these are radially arranged at the beginning and later compressed in a

cluster. The larval size is also variable.

The colours and spicule density seem less variable in material from the

eastern Atlantic Ocean and the western Mediterranean Sea than from the eastern

Mediterranean Sea. The variability of South African material identified as

C. dellechiajei thus precludes establishing a new species, a conclusion also

drawn by Millar (1962).

Distaplia skoogi Michaelsen, 1934

Figs 2C, 18A-C

non Holozoa domuncula Hartmeyer, 1913.

Distaplia domuncula: Millar, 1955: 187, fig. 15.

Distaplia skoogi: Michaelsen, 1924: 331, nov. nom. for Distaplia domuncula Michaelsen,

1923a: 15, fig. 3.

Material

Several colonies. Miller’s Point, False Bay, 4-15 m (Griffiths coll.).

Description

The colonies are large pads or balis, white, cream, mauve or light brown.

The common cloacal apertures open in simple holes with an unpigmented rim.

The zooids form conspicuous round systems as the oral siphons are circled with

white. The zooids are limited to the superficial layer of the colony. The oral

siphon has six low lobes. The cloacal siphon is either elongated in a tube with

no languet (Fig. 18B), or widely opened between a wide anterior lobe and a

posterior body wall extension (Fig. 18A). The thoracic musculature is thin with

regularly spaced oblique fibres. The four rows of stigmata are crossed by

parastigmatic vessels (Fig. 18A). There are 20-22 stigmata per side in the first

rows. The zooids are colourless except for the stomach, which is brown. The

stomach wall has internal thin ridges or areoles (Fig. 18A). The gut loop is wide

with a central pyloric ampulla (Fig. 18A). The gonads hang in a pedunculate

pouch behind the abdomen, with the testis vesicles clustered around a central

ovary (Fig. 18C).

SOUTH AFRICAN ASCIDIANS 35

eee

a) SS

SAN

Saas

yay

Fig. 18. A-C. Distaplia skoogi. A. Fully developed zooid. B. Zooid bud with gonads.

C. Gonads. D-G. Sycozoa arborescens. D-E. Zooids. F. Thoracic musculature.

G. Digestive tract.

The zooids were very young in the colonies examined and no trace of an

incubatory pouch or larvae was found, but gonads already appear in young

buds.

This species corresponds well with Millar’s (1955, 1962) descriptions for

D. domuncula. Our colonies were not attached to crabs but occur on hydroids

or soft corals.

36 ANNALS OF THE SOUTH AFRICAN MUSEUM

Remarks and distribution

Among the species that also have a smooth stomach wall and gonads in a

pouch below the abdomen, D. prolifera Kott, 1990, from western Australia,

differs by its encrusting colonies. Distaplia domuncula (Hartmeyer, 1913), from

False Bay, also has thick colonies with zooids in circular systems, but the

gonads were not developed.

Distaplia skoogi has been recorded from the Cape area, but has also been

collected by Monniot in 1995 at Ibo Island in Mozambique.

Sycozea arborescens Hartmeyer, 1912

Figs 2D, 18D-G

Sycozoa arborescens Hartmeyer, 1912: 316, pl. 38 (fig. 6), pl. 43 (fig. 6). Millar, 1962:

147, fig. 16; 1964: 166, fig. 5.

Material

One colony, intertidal cave in Old Harbour, Hermanus (Griffiths coll.).

Description

Several lobes arise from a common base, with round or laterally flattened

heads held on narrower peduncles. The zooids are arranged in vertical double

rows in the head, along cloacal channels. The common cloacal apertures form

an oval line internal to the edge of the flat upper surface of each lobe. The

colour in life is red and the tunic is translucent. No foreign matter adheres to

the tunic.

The zooids measure 1-1.5 mm in length. The oral siphon is cylindrical

without lobes (Fig. 18D, E). The cloacal siphon is either in a tube or gapes

more with a wide upper languet (Fig. 18F). The four rows of 12-14 stigmata

are grouped in pairs in the younger zooids (Fig. 18D, E). The abdomen is the

same length as the thorax. The stomach tapers posteriorly with no differentiation

into the intestine (Fig. 18G). Its wall is smooth, but it is slightly spotted when

stained. A large pyloric ampulla (Fig. 18G) is located inside the gut loop, and

joins longitudinal parallel tubules which surround the intestine to the anterior

part of the stomach. The colonies in this species are dioecious The colonies

examined were only male. Four to six testis vesicles at the bottom of the gut

loop protrude posteriorly (Fig. 18E). The sperm duct emerges posteriorly from

the centre of the barrel-shaped group of testis vesicles and curves anteriorly to

follow the rectum. No ovary or brood pouch were present.

Remarks and distribution

The present colonies correspond well with Hartmeyer’s (1912) and Millar’s

(1962, 1964) descriptions of S. arborescens, except for the common cloacal

apertures. Hartmeyer (1912) mentioned a single cloacal aperture on the top of

each lobe, but his plate 38 (fig. 6) suggests several apertures at the top of each

cloacal channel. Millar did not describe the common cloacal apertures and his

figures are not clear. Hartmeyer’s type (ZMB 2778) was examined and clearly

SOUTH AFRICAN ASCIDIANS 37

shows one common cloacal aperture at the top of each cloacal channel, and all

apertures placed around a dense core of tunic.

Sycozoa arborecens is only known from South Africa.

Fig. 19. Sigillina digitata. A-B. Zooids. C. Details of the gut.

Sigillina digitata (Millar, 1962)

Figs 2E, 19

Eudistoma digitata Millar, 1962: 155, fig. 20; 1964: 163.

Material

Several colonies, False Bay, in pools; Oudekraal, Cape Peninsula, 2-15 m

(Griffiths coll.).

38 ANNALS OF THE SOUTH AFRICAN MUSEUM

Description

Numerous colonies were collected in pools at low tide and deeper down to

15 m depth in the Western Cape area. They are large, very soft masses of

irregular lobes, some of them 150 mm across, either white, pink, or pale

brown. They are very often inhabited by numerous amphipods.The zooids open

both their siphons independently at the colony surface without any arrangement

into systems. The tunic is transparent and has a thin surface layer more resistant

than the gelatinous internal matrix.

The zooids are perpendicular to the colony surface with six lobed siphons

opening at the same level (Fig. 19A, B). The 24 tentacles alternate regularly in

three orders of size. The branchial sac has about 25 stigmata in a half-row.

About 20 thoracic longitudinal muscles extend through the abdomen and farther

to the long post-abdominal process. The stomach has a smooth wall. It is

followed by a wide mid-intestine that is clearly separated from the rectum by a

constriction in the descending limb of the gut (Fig. 19C).

The gonads consist of a long cluster of testis vesicles lying partially on the

gut loop and extending beyond it (Fig. 19B), and an ovary in the centre of the

testis (Fig. 19A). A long post-abdominal process contains longitudinal muscle

fibres and reserve cells. The heart is located inside the gut loop.

No larvae were found in the colonies examined, but a dilation of the

posterior part of the cloacal cavity containing an egg (Fig. 19B) was observed in

zooids having gonads.

Remarks and distribution

The present specimens collected in the Western Cape Province correspond

well with Millar’s descriptions of samples collected in the same area. The

gonadal extension under the gut loop is a characteristic of the species, even

when no larvae are present.

The distribution of S. digitata is restricted to South Africa.

Family Clavelinidae

Clavelina lepadiformis (Miller, 1776)

Riga

Ascidia lepadiformis Miller, 1776: 226.

Clavelina lepadiformis: see Berrill, 1950: 70, figs 14-15. Brunetti, 1987: 102.

Material

Several colonies. Knysna Estuary and Port Elizabeth Harbour (Griffiths and

Monniot coll.).

Distribution

This European species, well defined by its morphology and square stomach,

has recently been introduced to South Africa, probably on ship hulls. Clavelina

lepadiformis was previously recorded only along the European coast from the

SOUTH AFRICAN ASCIDIANS 39

latitude of Trondheim (Norway) down to the Mediterranean Sea, but has not

been found on the African Mediterranean coast. Isolated or introduced

populations have also been found in Morocco, Madeira and Azores Islands.

Family Didemnidae

Trididemnum cerebriforme Hartmeyer, 1913

Figs 2G, 20, 24A

Trididemnum cerebriforme Hartmeyer, 1913: 139, pl. 7 (fig. 1), pl. 8 (figs 4-5); Millar,

1982: 55, synonymy. Monniot, C. & Monniot, F., 1976a: 363. Monniot, F., 1990:

518, fig. 1. Nishikawa, 1990: 75.

Material

Several colonies. Saldanha Bay to Port Elizabeth (Griffiths and Monniot

coll.). Sodwana Bay, KwaZulu-Natal (Schleyer coll.). Mozambique (Monniot

coll.).

Description

Colonies of T. cerebriforme are very common along the South African coast

but vary remarkably in appearance. These range from thin encrustations to thick

colonies with a convoluted surface, but the consistency is always firm. Their

colour varies from light grey to pink-grey or dark grey. The colour and

thickness may vary in the same colony. In life the surface of the colonies is

smooth; when fixed the oral siphons protrude slightly, the spicules preventing

retraction. The basal layer of the colonies, in which the spicules are less dense,

often includes foreign matter.

The size of the zooids is also variable, being much larger in the thicker

areas than in thinner parts of the same colony. The oral siphon is either short

and lobeless or cylindrical with six lobes (Fig. 20A). It may be colourless or

contain black pigment. A black spot is located at the anterior extremity of the

endostyle. The cloacal siphon is tubular and differently oriented according to the

position of the zooid in the colony. The cup-like lateral thoracic organs, at the

level of the third stigmata row, may attain a very large size (Fig. 20A) or

remain small. There are 8-10 stigmata in the first row. The retractor muscle

emerges from the oesophageal peduncle (Fig. 20A) and can be longer than the

thorax.

The abdomen has no special characteristics. The gut loop is straight or more

or less twisted. The testis vesicle is conical (Fig. 20B) and covered with seven

or, rarely, nine sperm duct coils. The ovary develops after the testis.

The larvae are colourless and variable in size and structure in the same

colony (Fig. 20C, D). They possess an ocellus and otolith, three adhesive papil-

lae and on each side a variable number of lateral ampullae. At the beginning of

their development, these ampullae are well separated with four on each side

(Fig. 20C). During growth they increase in length and either remain undivided

or divide partially or fully, becoming bifid or doubled (Fig. 20D). As a result

there may be four, six, seven or eight ampullae on each side.

40 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 20. Trididemnum cerebriforme. A. Thorax. B. Abdomen. C-D. Larvae.

The spicules always have the same stellate shape with sharp rays

(Fig. 24A). Their abundance is variable from one colony to another. They are

always dense in the upper layer, especially around the oral apertures, but often

less numerous in the basal tunic. The spicule size and the number of rays are

variable, independent of the size of the colony.

Remarks and distribution

This species has always raised difficulties in its identification in different

parts of the world, and doubts remain about its being a single species. The

variability is universal, and nobody has been able to find distinctive

characteristics allowing the separation of species. It was first described in South

Africa but has since been found throughout the Western Indian Ocean, around

Australia, in the western tropical Pacific Ocean, and off Japan.

Didemnum aures F. Monniot sp. nov.

Figs 21, 24B

Material

Holotype. SAM-A25849, Port Elizabeth (33°59’S 25°39’E), intertidal,

collected by C. and F. Monniot, 14 Feb. 1996.

Other material. Several colonies, Gerickespunt (Sedgefield), intertidal

(Monniot coll.).

SOUTH AFRICAN ASCIDIANS 41

Description

This spectacular species forms large, bright red crusts 2-3 mm thick and

commonly 100 mm across. The colonies are smooth but appear convoluted

growing on uneven substrata such as algae, sand, shells, polychaete tubes and

many hard surfaces. The margin of the colonies is thick. The cloacal channels

are wide at the thoracic level, but narrower channels cross the deeper part of the

tunic. The stellate spicules are crowded throughout the full thickness of the

colonies.

Fig. 21. Didemnum aures sp. nov. A-B. Thorax. C-D. Both sides of the abdomen.

Ean:

The oral siphon is cylindrical, only slightly narrower than the long thorax

(Fig. 21A). The cloacal aperture is wide, extending along the four rows of

stigmata (Fig. 21A, B). There is no languet. On each side of the body wall, on

the margin of the cloacal aperture, a very large leaf-shaped lateral thoracic

organ protrudes like ears (giving the species its name) (Fig. 21A, B). We

counted 6-7 stigmata in the first half row (Fig. 21A). The retractor muscle is at

least as long as the thorax (Fig. 21B). The abdomen is folded under the thorax.

The gut loop has the usual shape with well-separated components (Fig. 21C, D);

it is folded on itself. The single testis vesicle (Fig. 21C) protrudes and is

covered by 7-9 coils of the sperm duct; it is pushed aside over the rectum when

a large oocyte develops.

Larvae were found in samples from Port Elizabeth (Fig. 21E). The trunk is

0.75 mm long and encircled by the tail. The visceral mass is separated from the

anterior ampullae and papillae by a constriction. The three parallel adhesive

42 ANNALS OF THE SOUTH AFRICAN MUSEUM

papillae are encircled by 12-16 ampullae, which are not regularly spaced or

necessarily of equal size. The larvae have no buds.

The spicules (Fig. 24B) are small, the largest 33 wm in diameter, and are

stellate with few conical rays.

The main distinctive characteristics of this species are the size and shape of

the lateral thoracic organs, and the structure of the anterior ampullae of the

larva. )

Didemnum epikelp F. Monniot sp. nov.

Figs 22, 24C

Material

Holotype. SAM-A25850, Gerickespunt (Sedgefield) (34°02’S 22°45’E),

intertidal, collected by C. and F. Monniot, 14 Feb. 1996.

Other material. Several colonies, locality as above, intertidal (Monniot

coll.).

Fig. 22. Didemnum epikelp sp. nov. A-B. Thorax. C-D. Both sides of the abdomen.

E. Larva.

Description

This white species encrusts kelp roots (hence the species name) in 1-mm

thick sheets of irregular outline. The colony surface is smooth. The tunic is

SOUTH AFRICAN ASCIDIANS 43

filled with spicules and is hard but not brittle. The zooids are small, 0.8 mm in

length when extended; the abdomen is normally folded under the thorax.

The oral siphon has six sharp lobes (Fig. 22A). The thorax is generally

contracted and the cloacal opening forms a simple hole or a transverse slit

(Fig. 22B) without a languet. The lateral thoracic organs are round leaves

(Fig. 22A, B) that protrude from the body wall mid-way down the thorax but at

some distance from the rim of the cloacal aperture. The waist is short. A short

retractor muscle arises from the base of the thorax (Fig. 22A, B).

The abdomen is larger than the thorax (Fig. 22C, D). The gut loop is

twisted. The stomach is spherical, large, followed by a post-stomach with an

annular swelling, a short mid-intestine, and a rectum of variable diameter but

always enlarged at its beginning. A large testis vesicle covers part of the

abdomen. Nine coils of the sperm duct are tightly pressed against the external

side of the spherical vesicle (Fig. 22C). The ovary develops in the middle of the

gut loop.

The larvae (Fig. 22E) have an elongated trunk 0.45 mm long. An ocellus,

otolith and some branchial perforations are present, but no bud. There are only

two adhesive papillae, with four pairs of digitate ampullae on each side

(Fig. 22E). In less advanced stages of development, the young tadpoles have

only three pairs of digitate anterior ampullae.

The spicules (Fig. 24C) are stellate, with short rays that are frequently cut at

their extremity. Their average diameter is 30 pm.

Remarks

This species has no special characteristics except the elongated larval trunk

with only two adhesive papillae. The thin crusts of this white didemnid with tiny

zooids do not correspond to the description of any other species of Didemnum in

the South African area. It may have been previously collected but wrongly

identified as Didemnum candidum (Savigny, 1816), as has occurred with many

other white Didemnum species worldwide. Lafargue (1974) established a

neotype of Didemnum candidum after she studied numerous colonies from the

Red Sea. Her description mentions larvae with three adhesive papillae.

Didemnum globiferum F. Monniot sp. nov.

Figs 2H, 23, 24D

Material

Holotype. SAM-A25851, Kommetjie, Cape Peninsula (34°08’S 18°19’E),

intertidal, collected by C. and F. Monniot, 5 Feb. 1996.

Other material. Several colonies, locality and collection details as above.

Description

The colonies encrust hard substrata in thin sheets about 1 mm thick and

commonly more than 100 mm across. Live specimens are pure white. The

common cloacal apertures are inconspicuous. The oral siphons are evenly

distributed, and form small holes on the very flat and smooth colony surface,

44 ANNALS OF THE SOUTH AFRICAN MUSEUM

giving it a spotted pattern. The spicules are densely packed throughout the

tunic, and the colonies would be brittle but for their thinness. The cloacal

channels are limited to the thoracic level. The abdomens of the zooids are

folded under the thoraces.

The oral siphon has six pointed lobes (Fig. 23A). The cloacal aperture is

large in relaxed zooids (Fig. 23A) but narrow in other parts of a same colony.

There is no languet. The lateral thoracic organs protrude above the two last

stigmata rows (Fig. 23A, B). There are 6-7 stigmata per side in the first

branchial row. The retractor muscle originates from the oesophageal peduncle,

and it is shorter than the thorax (Fig. 23A, B).

The gut loop has the usual shape found in the genus, the intestinal segments

being without apparent separations. A single large, conical testis lobe protrudes

from the middle of the gut loop and is covered by 7-9 coils of the sperm duct

(Fig. 23C). The ovary lies at the side of the testis (Fig. 23C).

The larvae (Fig. 23D) have an oval trunk 0.5 mm long with the tail

encircling three-quarters of the perimeter. An ocellus and otolith are present.

The three narrow adhesive papillae have four round ampullae on each side. The

larva is not gemmiparous.

The spicules are spheres, providing the species name, and the largest are

40 um in diameter. They consist of numerous rays, formed from parallel fibres

of similar length (Fig. 24D).

0.3 mm

Fig. 23. Didemnum globiferum sp. nov. A-B. Thoraces. C. Abdomen. D. Larva.

Remarks

This species looks like D. epikelp, but the colonies are larger and the zooids

are slightly different, and the larvae have three adhesive papillae instead of two.

The spicules are quite different, being spherical but not stellate.

SOUTH AFRICAN ASCIDIANS 45

Didemnum globiferum sp. nov. has spicules quite different from Didemnum

candidum Savigny, 1816, as redescribed by Lafargue (1974) or Didemnum

stilense Michaelsen, 1934.

Didemnum granulatum Tokioka, 1954

Didemnum moseleyi f. granulatum Tokioka, 1954: 244.

For a detailed synonymy see Monniot, F., 1994: 311.

Material

Several colonies. Port Elizabeth (Monniot coll.); Isipingo and Thompson’s

Pool, near Ballito, KwaZulu-Natal, intertidal (Griffiths coll.).

Description

The thin colonies are white or yellow with a rugose surface. The common

cloacal openings have a radially striated rim due to the arrangement of the

spicules in converging lines, a strong characteristic of this species. The cloacal

channels are wide as the very wide cloacal siphons of the zooids uncover most

of the branchial sac.

Remarks and distribution

All characteristics of the zooids and larvae correspond well to the

description of specimens collected in many other areas.

This species is widely distributed. It has been recorded in the western

Pacific off Japan, Fiji, New Caledonia, Australia, Polynesia, Hong Kong; and in

the Indian Ocean off South Africa, Mozambique, Tanzania and in the Red Sea.

It has also been found in the Atlantic Ocean off Brazil.

Didemnum leopardi F. Monniot sp. nov.

Figs 3A, 25, 29A

Material

Holotype. SAM-A25852, Sodwana Bay, KwaZulu-Natal (27°33’S

32°42’E), 14-15 m. Collected by M. Schleyer, Dec. 1992.

Other material. Two colonies, locality details as above (Schleyer coll.).

Description

The three colonies are the same in appearance. They form thin and hard

crusts, about | mm thick, with the surface slightly but regularly raised in small

white spots caused by accumulations of spicules. A pinkish brown network is

evident between these spots. The dark holes of the regularly spaced common

cloacal apertures give the surface a leopard-skin aspect (hence the species

name). The spicules are densely packed throughout the tunic. Large, brown,

spherical cells are numerous, especially in the superficial layer of the colony,

and probably represent symbiotic unicellular organisms. Brown pigment cells

46 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 24. Spicules. A. Trididemnum cerebriforme. B. Didemnum aures sp. nov.

C. Didemnum epikelp sp. nov. D. Didemnum globiferum sp. nov.

Scale bars = 10 pm.

SOUTH AFRICAN ASCIDIANS 47

Fig. 25. Didemnum leopardi sp. nov. A. Thorax of a mature zooid. B. Thorax of a young

zooid. C. Abdomen. D-E. Larvae.

are found throughout the tunic and especially in the zooids. The zooids are thus

brown and small, less than 1 mm long, with their thoraces perpendicular to the

colony surface and their abdomens folded under them. The cloacal channels are

restricted to the thoracic level.

The zooids have a narrow, cylindrical oral siphon with six pointed lobes

(Fig. 25A). The cloacal siphon is rather narrow in young zooids (Fig. 25B), and

has anterior and posterior lips which form a kind of beak. In more mature

zooids, the cloacal aperture is wider and these lips disappear (Fig. 25A).

The branchial sac has no anterior and posterior unperforated areas, and we

counted six stigmata on each side in the first rows. The lateral thoracic organs

are round, small, and located at the level of the third transverse vessel or fourth

row of stigmata. A large area of the basal part of the thorax is unperforated.

The retractor muscle (Fig. 25A) is at least equal in length to the thorax in

mature zooids, and originates from the oesophageal peduncle.

The gut loop is short (Fig. 25C) with a small stomach and a comparatively

large post-stomach. A spherical testis lobe protrudes from the posterior part of

the gut loop (Fig. 25C). Its external hemisphere is covered by 7-9 coils of the

sperm duct. The ovary appears and replaces the testis when it regresses.

The deeply pigmented larvae lie in the basal layer of the colony. The trunk

is 0.5 mm long and has an ocellus, an otolith, three adhesive papillae and four

pairs of anterior ampullae (Fig. 25E). In mature larvae (Fig. 25D), one of the

48 ANNALS OF THE SOUTH AFRICAN MUSEUM

anterior ampullae is sometimes partially divided and a vascular process appears

on the left side of the trunk between the visceral mass and the ampullae.

The spicules (Fig. 29A) are of uniform stellate shape, the largest being

35 ym in diameter. The rays are fibrous and have blunt tips.

The leopard pigmentation of this species is characteristic, as is the kind of

beak made by the anterior and posterior rims of the cloacal siphon in youns

zooids.

The colonies are inhabited by amphipods.

Didemnum mesembrinum F. Monniot sp. nov.

Figs 26, 29B

Material

Holotype. SAM-A25853, Knysna (34°04’S 23°03’E), intertidal. Collected

by C. and F. Monniot, 12 Feb. 1996.

Other material. Several colonies. As above and from Fish Hoek, intertidal

(Monniot coll.).

Fig. 26. Didemnum mesembrinum sp. nov. A. Thorax. B-C. Both sides of the abdomen.

D. Larva.

Description

The colonies are large crusts, about 1 mm thick and reaching 100 mm

across, covering all kinds of hard substrata. The colour in life is whitish or

cream. As the spicules are not very abundant, the oral apertures and the roof of

SOUTH AFRICAN ASCIDIANS 49

the cloacal channels merge into a darker marbled pattern. Some amphipods are

burrowed in the tunic, which also includes algae, shell debris, bryozoans,

polychaetes and sponges.

The zooids are very similar to those of Didemnum millari. The oral siphon

is cylindrical with six lobes (Fig. 26A). The cloacal aperture is narrow, closed

to a slit when the zooid is contracted. The lateral thoracic organs (Fig. 26A)

protrude in the middle of the thoracic wall at the level of the third transverse

vessel, sometimes spreading over two stigmata rows.

The long retractor muscle originates from the base of the thorax or the

proximal part of the oesophageal peduncle (Fig. 26A). The abdomen (Fig. 26B)

is larger than the thorax, and forms a narrow loop folded on itself with clearly

distinguished segments (Fig. 26B, C). The large testis follicle (Fig. 26B)

protrudes below the bottom of the gut loop, and its external pole is coiled with

6-9 turns of the sperm duct. The ovary develops between the testis and the

stomach (Fig. 26).

The larvae (Fig. 26D) have an ovoid trunk, 0.46 mm in length, three-

quarters of its perimeter encircled by the tail. The visceral mass is separated by

a constriction from the three anterior adhesive papillae, which are surrounded

by four pairs of elongated ampullae. The three rows of branchial stigmata are

already pierced (Fig. 26D) and gut differentiation has commenced, but there is

no bud. An ocellus and otolith are present.

The spicules (Fig. 29B) are small, their a maximum diameter being 25 yum.

They consist of many blunt rays of similar length but slightly different

thickness. The spicules in the tunic around the oral apertures are smaller than in

other parts of the colony.

Remarks

This species is closely allied to Didemnum stilense sensu Millar (1955) (non

D. stilense Michaelsen, 1934) for the anatomical characters of the zooids.

Nevertheless D. mesembrinum sp. nov. differs in several points: the different

appearance of the colonies, the lack of a mucous sheet at the colony surface, the

Sparser spicules and the cloacal channels that are visible from the surface. The

shape of the spicules is completely different. No pigment inclusions were found

in the basal layer of the colony, whereas they occur in the other species

collected in the same locality.

Both species, D. mesembrinum and D. millari (the new name for D. stilense

non Michaelsen, 1934; Millar, 1955, 1962), were probably combined as

a single species by Millar, who remarked that he was not satisfied that all

colonies belonged to the same species, noting that his identification was

tentative.

Didemnum millari F. Monniot sp. nov.

Figs 27A-D, 29C

non Didemnum stilense Michaelsen, 1934: 146.

Didemnum stilense: Millar, 1955: 176 (part.).

?Didemnum Stilense: Millar 1962: 164 (part).

50 ANNALS OF THE SOUTH AFRICAN MUSEUM

Material

Holotype. SAM-A25854, Woolley’s Pool, False Bay (34°08’S 18°26’E).

Collected by C. Griffiths and C. and F. Monniot, 22 May 1994.

Other material. Several colonies. Wooley’s Pool and Miller’s Point, False

Bay; Kommetjie (Griffiths and Monniot coll.). Common intertidally and

subtidally.

Description

The cream-coloured colonies are thin, soft and no more than a few

centimetres across. Numerous amphipods inhabit cavities in the colonies; their

entrances are clearly visible in the surface as slits.

Fig. 27. A-D. Didemnum millari sp. nov. A. Zooid. B, C. Both sides of the abdomen.

D. Larva. E-F. Didemnum obscurum sp. nov. E. Thorax. F. Abdomen.

The colonies encrust all kinds of material: rocks, shells, sponges, bryozoans

and algae. The colony surface is either smooth or raised in tiny spots as the oral

siphons protrude when the animal is contracted. The spicules are irregularly

distributed and sometimes give the colony surface a thinly reticulated

appearance under magnification. A very thin layer of tunic without spicules or

vacuolar cells covers the surface of the colonies, giving them a shiny

appearance. Orange inclusions are irregularly scattered within the basal part of

the tunic. The cloacal channels are restricted to the thoracic region.

SOUTH AFRICAN ASCIDIANS 3)

The six oral lobes of the zooids are pointed (Fig. 27A). The thorax is

smaller than the abdomen, always contracted, and has a low, small cloacal

aperture without languet. There are six stigmata in each half row. The lateral

thoracic organs are circular, protruding, often large, extending above the third

row of stigmata, and located in the middle of the thorax width (Fig. 27A). The

retractor muscle separates from the oesophageal peduncle (Fig. 27A).

The gut loop (Fig. 27C) is folded back on itself. The single testis vesicle

(Fig. 27B) is covered with 6-9 coils of the sperm duct and lies on the bottom of

the gut loop, with the ovary on its side.

The larvae are small (Fig. 27D), 460 pm in trunk length, with three

diverging narrow adhesive papillae and four pairs of lateral digitiform ampullae.

They are not gemmiparous.

The spicules (Fig. 29C) are stellate with few conical pointed rays, the

largest being 30 ym in diameter.

Remarks

This description corresponds relatively well with what Millar (1955, 1962)

tentatively identified as D. stilense Michaelsen, 1934, from the same geographic

area. However, our colonies do not correspond with the original description by

Michaelsen (1934), who stated that his species had no spicules in the surface

layer of the colony but possessed large bladder cells, and spicules ‘with very

numerous short conical spines’. In addition Michaelsen gave the colony

thickness as 9 mm, this being quite different to the thin crusts of D. millari.

Didemnum molle (Herdman, 1886)

Diplosomoides molle Herdman, 1886: 310.

Didemnum molle: see Monniot, F., 1994: 316, fig. 10.

Material

Several colonies, Sodwana Bay, KwaZulu-Natal, 15 m (Schleyer coll.).

Distribution

This urn-shaped species is very common in all tropical areas of the Indian

and western Pacific oceans. Its presence in KwaZulu-Natal probably represents

the southernmost distribution of the species. Didemnum molle contains abundant

mucus and unicellular symbiotic algae.

Didemnum ?obscurum F. Monniot, 1969

Figs 3B, 27E, F, 29D

Didemnum obscurum Monniot, F., 1969: 453; 1994: 319. Monniot, C. & Monniot, F.,

1997: 1626.

Material

Two colonies, Sodwana Bay, KwaZulu-Natal, 15 m (Schleyer coll.).

52 ANNALS OF THE SOUTH AFRICAN MUSEUM

Description

The two colonies from different stations are encrustations, 2-4 mm thick

with a smooth surface. The common cloacal openings are stellate. The colony

surface is very smooth and olive green to gold. The narrow cloacal channels are

limited to the thoracic level. The tunic is tough. The spicules are limited to a

thin layer at the colony surface and another at the interface with the substratum.

The tunic is filled with large vacuolar cells throughout its thickness. It is brown

in formalin.

The zooids only occupy the upper layer of the colony. They are dark brown

in formalin. The oral siphon has six short sharp lobes (Fig. 27E). The cloacal

languet (Fig. 27E) is very variable in size. It is wide around the common cloacal

aperture and has two lobes and a transverse musculature. Elsewhere, the

languet is small, T-shaped or simple. It is always fragile and difficult to extract

from the tunic. The lateral thoracic organs are round and protrude at the rim of

the body wall facing the second transverse vessel (Fig. 27E). The branchial sac,

dark brown in formalin, has 8-10 stigmata per side in the first row. The

retractor muscle is attached at the anterior part of the short waist (Fig. 27E).

The gut loop is flat (Fig. 27F). The single testis vesicle is particularly large,

filling almost the whole abdomen (Fig. 27F). The sperm duct has 8-9 coils. The

ovary develops simultaneously with the testis. Only one very young embryo was

found in a single colony. |

The spicules (Fig. 29D) are rather uniform in size and consist of numerous

sharp rays.

Remarks and distribution

Didemnum obscurum Monniot, F., 1969, was described from Dakar and

also collected at Bahrain, the Seychelles Islands and New Caledonia. The

samples from KwaZulu-Natal do not contain larvae, so the identification

remains uncertain. It is based on the similarity of the spicule shape and

distribution, the dark pigment and the zooid anatomy.

Didemnum psammathodes (Sluiter, 1895)

Leptoclinum psammathodes Sluiter, 1895: 11.

Didemnum psammathodes: for synonymy see Monniot, F., 1994: 324.

Material

One colony. Thompson’s Pool, near Ballito, KwaZulu-Natal (Griffiths

coll.).

Description

A very small piece of colony was collected at low tide. The tunic is filled

with faecal pellets, mixed with sparse spicules, except around the oral aperture,

where spicules are more abundant. The zooids are similarly arranged as in

colonies from other oceans (Monniot, F. 1983).

Didemnum psammathodes is widely distributed in the Atlantic Ocean from

the Caribbean islands to Brazil (Rocha & Monniot 1995), in the western

SOUTH AFRICAN ASCIDIANS 53

and central Pacific Ocean and the whole tropical Indian Ocean south to

KwaZulu-Natal.

Didemnum rodriguesi Rocha & F Monniot, 1993

Figg. 3¢

Didemunum rodriguesi Rocha & Monniot, F., 1993: 261, figs 1-2. Monniot, F., 1994: 326,

pl. 5A.

Material

Several colonies. Sodwana Bay, KwaZulu-Natal, intertidal to 22 m

(Schleyer coll.).

Description

Underwater, the colonies are orange with common cloacal apertures on the

top of swellings, circled with white. Under magnification, the colony surface

has the thin reticulated pattern of the spicular arrangment observed in Atlantic

and Pacific specimens. The spicules, zooids and larval anatomy are universally

identical.

The presence of Didemnum rodriguesi in KwaZulu-Natal, recorded

previously only from Brazil and New Caledonia, confirms that it has a

worldwide tropical distribution.

This species can easily be confused with Didemnum moseleyi in the absence

of larvae.

Polysyncraton ?aspiculatum Tokioka, 1949

Figs 3D, 28, 29E

Didemnum (Polysyncraton) aspiculatum Tokioka, 1949: 2, pl. 2 (figs 1-3). Kott, 1962: 301,

figs 36-38; 1975. Nishikawa, 1990: 111.

Material

Several colonies. Sodwana Bay, KwaZulu-Natal, 14-15 m (Schleyer coll.).

Djibouti, 5 m (Monniot coll.). Philippines, south of Maricaban Island

(13°38.39’N 120°55.86’E), 16 m (CRRF coll.).

Description

The colonies from KwaZulu-Natal are pure white, thick crusts of a soft

consistency. The spicules may be dense throughout the colonies, or limited to

the surface and basal layers. Large cloacal channels are apparent from the

surface as yellowish transparent lines delimiting irregular masses on the edges

of which the oral siphons open.

The general structure of specimens from Djibouti is similar, but with fewer

spicules and more pigment cells, giving the colonies a light brown colour. The

network of the cloacal channels is the same. The only difference in colonies

54 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 28. Polysyncraton aspiculatum. A-D. Specimens from South Africa. A. Thorax.

B. Abdomen. C-D. Larvae. E-G. Specimens from Djibouti. E. Thorax. F. Abdomen.

G. Larva.

from the Philippines is their darker brown colour caused by a greater abundance

of pigment cells in the tunic and zooids, and the absence of spicules.

The zooids are similar in structure to material from all of the above regions,

as well as to the type specimen loaned from the Seto Marine Biological

Laboratory.

SOUTH AFRICAN ASCIDIANS 55

The oral siphon is short with six lobes (Fig. 28A, E). The cloacal aperture

may be very wide in relaxed zooids, exposing a large part of the branchial sac

(Fig. 28A). The cloacal languet varies in shape according to its proximity to the

common cloacal aperture. Close to it, it is always large, with two thin, long

lobes (Fig. 28A, E), but these may be thicker and shorter elsewhere. The round

lateral thoracic organs are located over the second row of stigmata or over the

second transverse vessel. The branchial sac has ten stigmata on each side in the

three first rows.

The retractor muscle originates in the anterior from the oesophageal

peduncle (Fig. 28A, E).

The gut loop is wide open (Fig. 28B, F). The stomach is spherical and

relatively small. The testis vesicles are arranged in a rosette of 5-10 elongated

lobes, in the gut loop (Fig. 28B, F). The sperm duct is coiled in 3-5 loose

turns. The ovary lies inside the last turn of the sperm duct and the oviduct

follows the straight ascending part of the rectum.

Larvae were only present in colonies collected in KwaZulu-Natal, Djibouti

and the Philippines, not Japan. They are large (Fig. 28C, D, G), with a trunk

about 1 mm long and half encircled by the tail. Mature larvae have eight pairs

of elongated ampullae on either side of the three adhesive papillae (Fig. 28D),

resulting from the division of four pairs of ampullae in less developed tadpoles

(Fig. 28C). An ocellus and an otolith are present. One bud develops on each

side of the visceral mass.

The spicules (Fig. 29E) are about 30 um in diameter; they consist of needles

gathered in numerous rays to form balls. Their size varies according to their

density within the colonies. They are very small and located within the lateral

thoracic organs in the type colony described by Tokioka (1949). In colonies

from Djibouti, the spicules are only present in tracks at the colony surface. In

the specimens from KwaZulu-Natal, the spicules are sparse in some colonies

and more abundant in others (Fig. 29E).

Remarks and distribution

The identification of the South African colonies would have been very

speculative if the material had not been compared with samples from other

areas. The colour and the density of the spicules, being variable within the same

geographical region, do not allow us to separate the material into different

species. The type specimen and other colonies collected by Nishikawa were

examined but did not contain larvae.

Millar (1962) described Polysyncraton magnilarvum from a colony collected

in KwaZulu-Natal. He recorded it as having a greyish-pink colour, soft

consistency and few spicules. The description corresponds well with Millar’s

type specimen in the South African Museum. This confirms that Polysyncraton

magnilarvum is different from P. aspiculatum Tokioka, 1949, in having larger

spicules with fewer rays and larger larvae.

The distribution of P. aspiculatum is widespread, ranging from Japan to the

Philippines, southern Australia, Djibouti and South Africa, if the material

attributed to it consists of a single species.

56 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 29. Spicules. A. Didemnum leopardi sp. nov. B. Didemnum mesembrinum sp. nov.

C. Didemnum millari sp. nov. D. Didemnum obscurum. E. Polysyncraton aspiculatum.

F. Lissoclinum bilobatum. Scale bars = 10 um.

SOUTH AFRICAN ASCIDIANS ail

Polysyncraton millepore Vasseur, 1968

Fig. 3E

Polysyncraton millepore Vasseur, 1968: 917. Monniot, F. & Monniot, C., 1999: figs 7B,

8A-D, pl. 1D, E.

Material

Several colonies, Sodwana Bay, KwaZulu-Natal, 8-22 m (Schleyer coll.).

Description

The colonies are large, convoluted sheets, with a smooth surface irregularly

stained in tan and dark brown. The general consistency is hard, as the spicules

are very densely packed throughout the tunic thickness.

The species has been recorded from Madagascar, Mozambique, and

KwaZulu-Natal in South Africa, but not further south.

Atriolum marsupialis F. Monniot, 1989

Fig. 30C

Atriolum marsupialis Monniot, F., 1989: 674, text-fig.1, pl. 1A.

Material

Two colonies. Sodwana Bay, KwaZulu-Natal, 15 m, on Polycarpa (Schleyer

coll.); Ibo Island, Mozambique, 10 m (Monniot coll.).

Description

The largest colony is 25 mm across and 3 mm thick. The colour is

yellowish. The tunic is soft but resistant, containing few spicules in a single

layer at the colony surface, sometimes gathered in white trails in the surface

layer, which has small, irregular, erect papillae. Tracks of orange pigment and

dark pigment cells are present in the basal tunic. Zooids and larvae are

colourless. The cloacal channels are narrow.

The oral siphon is long compared to the zooid size, and without lobes at

its rim. It is closed by a strong basal sphincter. The cloacal siphon is located

at the postero-dorsal angle of the thorax. It has a peculiar shape: a

sphincter encircles the cylindrical tube, the free extremity of which is divided

in two unequal lips with the posterior lip being larger and curved in a kind

of spoon. Both lips are edged with a crescent of transverse muscle fibres.

The thorax is wide and almost square. Its wall has about ten longitudinal

fibres on each side that are regularly spaced and not ramified. The lateral

thoracic organs are located above the third transverse vessel in the middle of

each side.

The branchial sac has four rows of 14 stigmata per side behind an

unperforated area of one stigma length. An incubatory pouch with a narrow

peduncle arises in the posterior part of the thorax against the oesophageal

peduncle. There is no retractor muscle.

58 ANNALS OF THE SOUTH AFRICAN MUSEUM

The waist is narrow and the abdomen is folded under the thorax. The gut

loop is made of a narrow cylindrical oesophagus, a spherical stomach with a

smooth wall, a conical post-stomach and an oval mid-intestine separated from

the rectum by a constriction. The anus opens at the level of the third row of

stigmata.

Five to seven testis vesicles in a rosette are covered by 7-8 coils of

the sperm duct. The ovary develops against the testis. Two or three

vascular processes arise from the centre of the gut loop on the side opposite the

gonads.

The larvae (Fig. 30C) are brooded in the basal layer of the tunic, but only

young, empty brood pouches were found attached to the zooids. The trunk is

0.65 mm long and spherical with the tail encircling three-quarters of the

perimeter. The three adhesive papillae are thick, in a line, with four large,

rounded ampullae on each side. The papillae and vesicles are separated from the

visceral mass by a constriction. The larval branchial sac is already developed,

as are the different parts of the digestive tract. A vascular process is

differentiated on the right side of the larva, but there are no buds. The spicules

are stellate, with numerous sharp rays.

Remarks and distribution

The African samples correspond exactly to Atriolum marsupialis,

as described from New Caledonia. Only two other species of Atriolum have

been described: Atriolum quadratum Monniot, F. & Monniot, C., 1996,

from the western Pacific at Chuuk Island, and recently found again in

Mozambique; and Atriolum robustum Kott, 1983, from the north of Australia

but also present in New Caledonia (Monniot, F. 1990), Madagascar

(Millar 1988), Mayotte (Comoros islands) and Mauritius (Lafargue & Vasseur

1989).

Lissoclinum bilobatum Millar, 1955

Figs 29F, 30A, B

Lissoclinum bilobatum Millar, 1955: 180, fig. 11. Plante & Vasseur, 1966: 146, pl. 2

(fig. 11).

Material

Several colonies. Thompson’s Pool, near Ballito, KwaZulu-Natal (Griffiths

coll.); Port Elizabeth, intertidal (Monniot coll.).

Description

The colonies are thin and pink or white encrustations of a soft consistency.

The colony surface is smooth. The oral apertures are stellate. The cloacal

channels are very wide.

The zooids have a short oral siphon (Fig. 30A). The wide cloacal aperture

uncovers a large part of the branchial sac. A round languet is present (Fig. 30A)

but is sometimes is very small and barely visible. The round, protruding lateral

organs are located at the level of the second transverse vessel. There are eight

SOUTH AFRICAN ASCIDIANS 59

stigmata in the first and second half rows. The retractor muscle is absent. The

abdomen is folded under the thorax. The gut loop is very narrow and contains a

large, clear vesicle (Fig. 30B). The testis lies over the intestine and has two

longitudinal lobes (Fig. 30B). The sperm duct is straight and enlarged at its start

when the testis is fully developed.

Some larvae were present in a pink colony collected at Port Elizabeth. The

trunk is 0.65 mm long and entirely covered with large pigment cells, which are

dark brown in formalin. All larvae are immature and only have three adhesive

papillae and an indication of four pairs of lateral ampullae.

The spicules (Fig. 29F) are generally small, 20 wm in diameter, but there

are a few larger ones up to 35 pm. They are balls made of numerous rays of

parallel needles which are rather irregularly spaced.

Zeew Go’ wae:

i &Q) Ow \

Bir Fe O90 ig f Neate

Neg, ©0908 fasthy :

= 2 .

Se lg

“S

0.3 mm

Fig. 30. A-B. Lissoclinum bilobatum. A. Thorax. B. Abdomen.

C. Atriolum marsupialis. Larva.

Remarks and distribution

It was difficult to identify this species, as Millar’s (1955) type could not be

found at the British Museum. The description corresponds well with our

specimen as well as the spicule size. Millar did not mention the cloacal languet

or retractor muscle and they are absent in his figure.

This Lissoclinum species is closely allied to the Atlantic Lissoclinum fragile

(Van Name, 1902) as described by Monniot, F. (1983). The zooids and spicules

are similar. In the absence of mature larvae in the South African colonies, we

prefer to retain Millar’s name, L. bilobatum. Further collections of colonies

with larvae would perhaps allow us to synonymize both species.

The species distribution is presently restricted to Madagascar and the east

coast of South Africa.

Lissoclinum bistratum (Sluiter, 1905)

Leptoclinum bistratum Sluiter, 1905: 18, pl. 2 (fig. 10).

For detailed synonymies see Kott, 1982: 112; Monniot, F., 1992: 566, text-fig. 1, pl. 1A.

60 ANNALS OF THE SOUTH AFRICAN MUSEUM

Material

Several colonies. Sodwana Bay, KwaZulu-Natal, 19 m (Schleyer coll.).

Distribution

This species contains abundant symbiotic unicellular algae. It is very

common in the western tropical Pacific Ocean and in all the tropical Indian

Ocean from the extreme north to KwaZulu-Natal.

Diplosoma listerianum (Milne-Edwards, 1841)

Leptoclinum listerianum Milne-Edwards, 1841: 300.

For a description and synonymy see Lafargue, 1968: 406, fig. 9; Monniot, F., 1983: 41.

Monniot, C. & Monniot, F., 1987: 59.

Material

Several colonies. In all harbours from Saldanha Bay to Port Elizabeth.

Remarks and distribution

This European species has invaded numerous harbours in temperate and

tropical areas in the Atlantic, Pacific and Indian oceans. It is commonly found

on ship hulls and grows in thin soft sheets or thicker pads. The colony colour

varies from white to dark grey.

Diplosoma virens (Hartmeyer, 1909)

Leptoclinum virens Hartmeyer, 1909: 1456. (nom. nov. for Diplosoma viride Herdman,

1906.)

For a detailed synonymy see Monniot, F. & Monniot, C., 1996: 170.

Material

Several colonies. Rocky Bay, KwaZulu-Natal, 2 m (M. E. Aken coll.).

Remarks and distribution

The zooids and larvae are identical to western Pacific samples. All colonies

have symbiotic algae. This species is widely distributed in shallow tropical

waters in the Pacific and Indian oceans.

Family Cionidae

Ciona intestinalis (Linné, 1767)

Ciona intestinalis see Berrill, 1950: 131, figs 40-41. Hoshino & Nishikawa, 1985,

fig. LA-C, 2, 4.

Material

Several colonies. Cape Town; Hout Bay; Port Elizabeth (Griffiths and

Monniot coll.).

SOUTH AFRICAN ASCIDIANS 61

Remarks and distribution

Ciona intestinalis originated in the northern Atlantic Ocean, but has invaded

harbours throughout temperate and subtropical climes.

This species was recorded by Millar (1955) in Durban Harbour and by

Millar (1962) in Saldanha Bay. We collected this species in several harbours

such as Saldanha Bay, Cape Town, Hout Bay and Port Elizabeth. The

specimens from Hout Bay have short siphons circled by a thick rod of tunic that

is somewhat tuberculated. This morphology is sometimes encountered in

European harbours. On the contrary the red form of this species, which is

occasionally found in Europe, has not been recorded in South Africa.

Family Perophoridae

Ecteinascidia modesta C. Monniot sp. nov.

Fig: 311

Material

Holotype. SAM-—A25855, Knysna Estuary (34°04’S 23°03’E), collected by

C. and F. Monniot, Feb. 1996.

Other material. Several colonies. Locality details as above.

Fig. 31. Ecteinascidia modesta sp. nov. A. Left side of body. B. Dorsal area.

C. Gut and gonads.

Description

The colonies of small zooids (3 mm) are colourless and live on bryozoan

crusts. The individuals are isolated, sometimes have a short peduncle, and are

62 ANNALS OF THE SOUTH AFRICAN MUSEUM

united by a network of stolons. The oral siphon is on the top, and the cloacal

siphon somewhat lateral. Both apertures are encircled by six flat lobes

indented by deep clefts. The musculature (Fig. 31A) comprises about 20 thin

oblique and regularly spaced roughly parallel ribbons. They originate from a

region on each side of the body that runs from below the oral siphon to below

the cloacal siphon and includes the intersiphonal space (Fig. 31A). About

30 oral tentacles in three orders of size do not regularly alternate in a ring at

mid-length of the oval siphon (Fig. 31B). The prepharyngeal groove has

two inequal rims, the anterior higher. The urn-shaped dorsal tubercle

opens through a round hole (Fig. 31B). The dorsal lamina consists of

languets united by a basal membrane which is half the height of a languet

(Fig. 31B).

The branchial sac has 11 rows of stigmata and 12-13 generally entire

longitudinal vessels on each side. About 25 stigmata, consequently two per

mesh, are counted in a row. We did not observe divisions of stigmata or of

rows of stigmata. The. posterior row is somewhat irregular. The oesophagus

enters the posterior side of an oval stomach (Fig. 31C). The intestine is divided

into three parts by constrictions; it has no caeca. The simple anus opens

between the fifth and sixth row of stigmata.

The ovary contains numerous poorly developed oocytes. The testis

(Fig. 31C) is ventral to the ovary and consists of elongated lobes that protrude

just beyond the external edge of the gut. The wide sperm duct opens through a

papilla adjacent to the anus. The oviduct extends to the right side of the body.

The ovary was not mature and no larvae were found.

Remarks

This species is characterized by its small number of stigmata rows (11) and

oblique musculature. It differs from FE. multistigmata (= Perophora

multistigmata Kott, 1952) from Queensland, which has fewer stigmata rows

(eight), a musculature with numerous fibres more complex in origin and a single

testis with few lobes. It is closely allied to E. bandaensis Millar, 1975, from

Indonesia, Philippines, Madagascar and Mozambique (Monniot, F. & Monniot,

C. 2001), a species with similar musculature but 16 stigmata rows, a globular

stomach and a testis made of very numerous small lobes surrounding the ovary.

In addition, E. bandaensis has an opaque tunic with a red line encircling the

siphons.

Ecteinascidia modesta superficially resembles the small northern

Atlantic species E. minuta Berrill, 1932, and E. herdmani (Lahille, 1887),

but the gut loop is narrower and the stigmata more numerous in both those

species.

The species name Ecteinascidia modesta refers to its very discrete presence,

making it difficult to notice in the field.

Ecteinascidia thurstoni Herdman, 1891

Ecteinascidia thurstoni, Monniot, C. & Monniot, F., 1997: 1630, fig. 4.

Ecteinascidia hedwigiae Michaelsen, 1918: 60, pl. 1 (figs 1-2).

SOUTH AFRICAN ASCIDIANS 63

Material

One colony, Isipingo, KwaZulu-Natal (Griffiths coll.); Knysna, young

specimens (Monniot coll.).

Distribution

This species was described from material collected in Sri Lanka and later

from specimens collected in Western Australia, the Arabian Gulf, Djibouti,

Tanzania and Mozambique. It is the only record of the family Perophoridae in

South Africa that has been previously described.

Family Corellidae

Corella eumyota Traustedt, 1882

Corella eumyota Traustedt, 1882: 17, pl. 4 (figs 2, 3), pl. 5 (figs 13, 14).

Material

Two specimens. Saldanha Bay Harbour (Monniot coll.).

Remarks and distribution

This species was recorded for the first time in Cape Town by Sluiter

(1898a) and found again by Michaelsen (1934) and Millar (1955, 1962). It

inhabits seas around Antarctica, Tasmania, South Australia, and the southern

part of South America. In the Atlantic Ocean it was recorded off Tristan da

Cunha by Millar (19676), and Namibia by Michaelsen (1915) and Turon (1988).

The adult South African specimens are small (20 mm) compared to

individuals from the Antarctic, which attain 100 mm. The branchial sac is less

developed with fewer coils of stigmata. The development of the branchial sac

and the gut in this species varies according to environmental conditions

(Monniot, C. & Monniot, F. 1983). Numerous eggs were present in the cloacal

cavity in samples from New Zealand, and Lambert et al. (1995) described

brooded larvae.

Family Ascidiidae

Ascidia canaliculata Heller, 1878, part of A. sydneiensis aut. mult.

Fig. 32

Ascidia canaliculata Heller, 1878: 84, pl. 1 (fig. 1). Sluiter, 1898a: 41, pl. 5 (figs 15-18).

Michaelsen, 1921: 5.

Phallusia canaliculata: Hartmeyer, 1911: 576, pl. 57 (figs 13-14).

Phallusia longitubis Traustedt, 1882: 283.

Material

Several specimens. Fish Hoek, False Bay (Monniot coll.).

64 ANNALS OF THE SOUTH AFRICAN MUSEUM

Description

Ascidia canaliculata is closely allied to A. sydneiensis Stimpson, 1855. Both

species were synonymized by Van Name (1921). They have in common large,

grooved siphons with digitate lobes and a characteristic transverse musculature

limited to the right side of the body (Fig. 32B). The musculature consists of two

ribbons of parallel fibres, one ventral and one dorsal. These ribbons are linked

by very thin fibres which become visible when stained (Fig. 32B). The gut

always has a bulbous widening of the posterior intestine filled with sediment

(Fig. 32A) even in very young individuals.

Fig. 32. Ascidia canaliculata. A. Left side of body. B. Muscles on the right side.

C. Dorsal tubercle.

Remarks and distribution

The only distinguishing characteristic of the species is the structure of the

dorsal tubercle (Fig. 32C). In all the Atlantic, South African and Mozambican

populations this has the shape of a ‘V’ that is open anteriorly and has horns

curled interiorly. It is not regular in pattern but rather undulated (Fig. 32C). In

A. sydneiensis, a Pacific Ocean species, the dorsal tubercle is pierced by several

openings. Authors who have examined both species consider them distinct

(Sluiter 1898a; Hartmeyer 1911), except for Millar (1955) who was doubtful.

Ascidia sydneiensis is somewhat variable in the Pacific. Tokioka (1953)

recognized three subspecies in Japan: A. sydneiensis sydneiensis, which has a

SOUTH AFRICAN ASCIDIANS 65

simple dorsal tubercle; and A. sydneiensis divisa and A. sydneiensis samea,

whose divided dorsal tubercles differ. Nishikawa (1991) examined the same

material and showed that the position of the gut is variable and that the dorsal

tubercle is simple in small specimens before becoming more complex with

growth. He thus did not recognize Tokioka’s subspecies. An undulated opening

is not mentioned in any description of A. sydneiensis, the shape usually being

described as a ‘C’ open to the left side with horns slightly curved.

Although all specimens from the Atlantic Ocean, South Africa and Mozam-

bique correspond to A. canaliculata, those from the western coast of Australia

have complex dorsal tubercles (Kott 1985) and correspond to A. sydneiensis. In

Mauritius, Vasseur (1967) described A. sydneiensis as having simple or divided

dorsal tubercles; he found Tokioka’s three variant morphologies but refused to

use the subspecies. In Sri Lanka, Herdman (1906) described small specimens

24 mm in length, and these had a simple dorsal tubercle.

Traustedt & Weltner (1894) recorded the presence of Phallusia longitubis in

the Indian Ocean without providing a description.

Taking this disparity of characters into account and noting the limits of

variability in A. sydneiensis after all, we believe that A. canaliculata and

A. sydneiensis are different (vicariant) species.

Ascidia caudata Heller, 1878

igs s333

Ascidia caudata Heller, 1878: 85, pl. 2 (fig. 2).

Material

Several specimens. False Bay, low tide (Monniot coll.).

Description

Ascidia caudata has not been recorded in South Africa in over a century.

This is rather surprising as it is a common species at 1-2 m depth and attains a

size of 25 cm. It inhabits narrow crevices and the underside of large boulders

where there is a space of some centimetres between the rock and the sediment.

The ascidians are attached to the rock on their whole left side, including the

siphons. The right side of the body and the siphons are generally covered with

large shell fragments and gravel. The long siphons diverge and they may be

15 cm apart. The colour of the tunic surface varies from yellow to brown or

almost black, according to the distance from the edge of the rock, the pigment

being light-induced. The remainder of the tunic is pale grey or yellowish.

In life the body wall is sulphur yellow, pigmented by blood cells. When

fixed these cells turn black (as in many Ascidiidae rich in vanadocytes). The

tunic is thin on the left side of the body but forms a pad that protrudes internally

between the posterior intestine and the rectum. The siphons do not show lobes.

The muscles are strong on the right side, mostly transverse with some fibres

issuing from the cloacal siphon in the anterior part of the body. The muscles are

dense over the gut, almost joined, but more diffuse posteriorly. The left side of

the body wall and the tip of the siphons are devoid of musculature.

66 ANNALS OF THE SOUTH AFRICAN MUSEUM

C Il

Fig. 33. Ascidia caudata. A. Left side of body of a large specimen. B. Testis on the gut of

a small specimen. C. Dorsal tubercle.

More than a hundred oral tentacles are located on a thin high crest in large

specimens. They are 4 mm long, almost all equal in size (Fig. 33C) and form a

kind of comb that closes the oral aperture. The prepharyngeal band has two

equal rims. The dorsal tubercle (Fig. 33C) consists of two masses of tissue

pierced by numerous holes. The neural ganglion is close to the dorsal tubercle.

The low dorsal lamina has a smooth margin, which is stiffly delineated only on

the left side. The oesophagus entrance is located anteriorly to the bottom of the

branchial sac. It is large, sometimes smooth or with protruding crests. On the

right side of the branchial sac, the extremities of the transverse vessels form

hooks linked by a membrane. The branchial internal longitudinal vessels only

bear large papillae. The vessels are close to each other in small specimens

(7 cm) and the square meshes contain, on average, three small stigmata. In large

individuals, the meshes lengthen transversally and may have seven stigmata.

The transverse vessels are wide on the external side of the branchial sac; they

are linked together and form an irregular network covering at least half of the

branchial surface, even in young specimens. The fragile branchial tissue is

linked to the body wall by numerous short connections. The cloacal cavity is not

Spacious.

The gut describes a double loop (Fig. 33A, B). The exact path of the

digestive tract is difficult to follow even in small specimens, as the visceral mass

SOUTH AFRICAN ASCIDIANS 67

is rendered opaque by testis vesicles (Fig. 33B). The ovary is also hidden. The

anus is very small, has a plain margin and opens in the centre of the visceral

mass (Fig. 33B).

Distribution

Ascidia caudata has only been recorded from the Cape Peninsula, South

Africa.

Ascidia incrassata Heller, 1878

Fig. 34

Ascidia incrassata Heller, 1878: 88, pl. 2 (fig. 8). Michaelsen, 1934: 154.

Material

Several specimens. Miller’s Point, False Bay, 2-10 m. (Griffiths coll.);

Saldanha Bay Harbour (Monniot coll.).

Description

The largest specimens from Miller’s Point are erect, about 100 mm long and

only attached on the left posterior side. The tunic is translucent, hard, somewhat

cartilaginous, up to 20 mm thick and covered with epibionts. The siphons are

naked and protrude, the oral siphon to the anterior and the cloacal siphon

towards the anterior quarter of the body. Both siphons have 6-8 lobes that are

prolonged by a transparent tip. There is a red spot between each lobe. The

colour in life is purple or red; it disappears in formalin. The small specimens

from Saldanha Bay, 40 mm long, are deep red in life and the colour persists for

some time in formalin, but fades.

Muscles are only present in the dorsal part of the body wall. These are

symmetrically distributed on the sides of the body (Fig. 34A, B, D, E), an

exceptional characteristic among the Ascidiidae. These probably provide an

erect posture to these animals and stiffness to the tunic. In large specimens,

there are about 60 oral tentacles on a crest, in 3-4 orders of size, with an

underlying muscular ring. The prepharyngeal groove has two equal edges and is

curved slightly dorsally. The neural ganglion is anterior near the protruding

dorsal tubercle. The dorsal tubercle is C-shaped with an anterior opening and

curled horns (Fig. 34G). The dorsal lamina is doubled above the neural

ganglion and posteriorly forms a raised blade with small teeth on the rim. The

transverse thickenings do not reach the edge of the blade and have no

relationship to the teeth. The dorsal lamina encircles the oesophagus entrance;

at this level and on the right side, the transverse vessels form a dented

membrane (Fig. 340H).

The branchial tissue is undulated with 40 and 32 longitudinal vessels on the

right and left sides respectively. The main papillae are large. The elongated

branchial meshes may have up to 12 short stigmata. The branchial sac does not

extend posteriorly under the digestive tract.

The gut of the largest specimens is totally enclosed in whitish tissue that

consists of an accumulation of vesicles and testis lobes that largely conceal a

68 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 34. Ascidia incrassata. A-B. Both sides of a large specimen. C. Gut and gonads of a

large specimen. D-E. Both sides of a small specimen. F. Gut and gonads of a small

specimen. G. Dorsal tubercle of a small specimen. H. Oesophagus entrance of a small

specimen.

marked double gut loop (Fig. 34B, C). The stomach folds are not evident

externally. The intestine, which is uniform in diameter, ends in small anal

lobes. Although it is difficult to discern the shape of the different organs in large

Specimens, it is easier to observe the gut and gonads in small specimens from

Saldanha Bay (Fig. 34E, F). They are mature and have numerous eggs in the

cloacal cavity. They correspond to the descriptions of Ascidia multitentaculata

SOUTH AFRICAN ASCIDIANS 69

by Hartmeyer (1912) and Millar (1964). They possess a large number of oral

tentacles (more than 160) (Fig. 34G). The reduction in tentacle number during

the growth to a larger size has been described several times, particularly by

Millar (1960) for Ascidia translucida and Cnemidocarpa verrucosa. The

branchial sac of small specimens has a similar number of longitudinal vessels as

larger ones (36 on the right and 34 on the left), but the branchial meshes are

square and enclose an average of seven stigmata. We found numerous

duplications of the stigmata rows marked by intermediate papillae. The gut

makes a double loop (Fig. 34E, F). The ovary is located in the primary loop and

consists of numerous tight lobes that do not protrude beyond the gut loop. The

testis covers most of the gut on both sides (Fig. 34E, F).

Remarks and distribution

Ascidia incrassata is only known with certainty from the Western Cape

area, where it was last collected in 1931 (Michaelsen 1934). It possibly occurs

in southern Mozambique (Michaelsen 1918). Michaelsen noted that

A. multitentaculata differs from A. incrassata only in the number of oral

tentacles, and proposed that it be considered a variety of the latter. Ascidia

multitentaculata was only known from three specimens. Millar (1977: 204,

fig. 24) described from Salvador Beach (Brazil) an additional specimen of

similar size, which had very numerous tentacles and an S-shaped gut. The

Brazilian specimen differs from the South African material, having muscles

over the whole right side, more longitudinal vessels (80), no intermediate

branchial papillae and an ovary in two parts, located within the two intestinal

loops. Millar (1977) considered his identification doubtful, and this is also our

opinion.

The specimen of A. incrassata from Inhaca described by Millar (1956) has

the musculature and dorsal tubercle characteristic of A. canaliculata.

Ascidiella aspersa (Miller, 1776)

Ascidia aspersa Miller, 1776: 225.

For synonymy see Berrill, 1950: 154, fig. 47.

Material

Several specimens. Saldanha Bay Harbour; Cape Town; Hout Bay; Port

Elizabeth (Monniot coll.).

Distribution

Ascidiella aspersa is an European species whose distribution extends from

Norway (Trondheim Fjord) to the Mediterranean Sea and the Atlantic coast of

Morocco. It has been recorded in Senegal as (Ascidiella senegalensis

Michaelsen, 1915). Brewin (1946) noted its voluntary importation into the south

of New Zealand. This species has now invaded harbours and lagoons in

southern Australia. It has also been collected in Porto Nuovo Bay, Argentina

(42°53’S 64°42’W).

70 ANNALS OF THE SOUTH AFRICAN MUSEUM

Family Styelidae

Botryllus closionis C. Monniot sp. nov.

Figs 3G, 35

Sarcobotrylloides racemosum Hartmeyer, 1912: 274, pl. 37 (fig. 5), pl. 41 (fig. 9).

non Botryllus racemosus Quoy & Gaimard, 1834: 620, pl. 92 (figs 7-8).

Material

Holotype. SAM-A25856, Sea Point, Cape Town (33°55’S 18°23’E), low

tide. Collected by C. L. Griffiths, 25 May 1994.

Other material. Several colonies, locality data as above (Griffiths and

Monniot coll.).

Description

This species has a characteristic appearance in the photograph and in

Michaelsen’s colour plate (1912, pl. 37 (fig. 5)). The red zooids form circular

systems in hollows of the upper tunic, giving the colony surface a partitioned

pattern as suggested by the species name (closis = fence). It covers both sides

of the fronds of the seaweed Epymenia. The tunic has a firm constistency.

The zooids (Fig. 35A, B) are 1.5-2 mm long and perpendicular to the

colony surface. A large cloacal languet lies above a very wide cloacal opening

which reveals a large part of the branchial sac (Fig. 35A, B). There are nine

rows of stigmata. The branchial sac is asymmetrical: the two first rows are

complete on the right side (Fig. 35B), but the second row does not reach the

dorsal lamina on the left side (Fig. 35A). There are 12-15 stigmata in a half-

row and 2-3 stigmata between the longitudinal vessels.

The oval stomach wall has about ten protruding folds that are slightly

enlarged anteriorly.

The caecum is long, curved, and has a small dilation at the tip (Fig. 35A).

The gut loop is short. The pyloric gland is not well developed. The anus opens

at the level of the seventh stigmata row at the base of the exposed part of the

branchial sac and has a smooth edge (Fig. 35A, B).

Each zooid is linked to the vascular network of the colony by several

sinuses.

In the colony studied, the nourishing zooids only have rudimentary testes

(Fig. 35A, B). The first-order buds have mulberry-shaped testes that are more

developed than in the adult zooids. Several oocytes are present in the second-

order buds.

Remarks

The description of Botryllus racemosus by Quoy & Gaimard (1834) from

Australia is short and could apply to any Botryllus with circular systems. The

drawings (pl. 92 (figs 7-8)) clearly show systems of zooids at the tunic surface,

thus depicting material that does not belong to this species.

Sarcobotrylloides racemosum Hartmeyer, 1912, was synonymized with

Botryllus leachi by Hartmeyer & Michaelsen (1928), with B. magnicoecus by

SOUTH AFRICAN ASCIDIANS 71

0.5 mm

Fig. 35. Botryllus closionis sp. nov. A-B. Both sides of a zooid.

Tokioka (1967), and with B. schlosseri with some doubt by Kott (1985).

Botryllus schlosseri sensu Kott, from Australia, is a different species from the

European B. schlosseri and belongs to B. aster Monniot, C., 1991. None of the

above synonymies are valid. The partitioned appearance of the colonies and its

circular systems separate it from all other species of the genus.

Botryllus elegans (Quoy & Gaimard, 1834)

Figs 3H, 36

Distomus elegans Quoy & Gaimard, 1834: 623, pl. 42 (figs 11-13).

Synstyela monocarpa Sluiter, 1898a: 55, pl. 1 (figs 12), pl. 7 (figs 5-8).

Chorizocarpa elegans: Hartmeyer, 1912: 266. Michaelsen, 1915: 413, pl. 18 (fig. 37).

Botryllus anomalus Millar, 1962: 175, fig. 28. Monniot, C. & Monniot, F., 1976a: 359.

Material

Several colonies. Table Bay, Sea Point on Epymenia fronds (Griffiths and

Monniot coll.).

Description

The colonies were thin encrustations on sea-weed fronds. The common tunic

is transparent, often bluish with yellow circulatory ampullae of the tunic’s blood

system. The ampullae do not form a ring around the edge of the colony as is

often the case in the genus. The zooids are spherical and regularly distributed.

W2 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 36. Botryllus elegans. A. Dorsal side of a zooid. B. Ventral side of a zooid.

C. Bud with gonads.

There are no systems; the cloacal siphons of the zooids open independently. The

zooids are generally similarly orientated in the colony. There are white pigment

spots that vary in number on the edge of the siphons.

The body wall is often yellow, except where it is red around the siphons and

dorsally. All colour disappears after fixation.

We counted eight short oral tentacles. Three branchial longitudinal vessels

on each side cross eight rows of oval stigmata. The gut (Fig. 36B) forms a

closed loop. The globular stomach bears anterior grooves. The caecum has the

shape of a pedunculate vesicle (Fig. 36B). The pyloric gland is small and does

not encircle the intestine. The anus has a plain margin. The gonads are well

developed. On each side there is a massive lobed testis ventrally (Fig. 36B) and

a large egg dorsally (Fig. 36A). In some zooids the egg is segmented in four

blastomeres.

We rarely observed even slightly developed buds in our material, but the

few we found possessed Botryllus characteristics, i.e. gonads differentiated at

the beginning of branchial development (Fig. 36C). No larvae were brooded in

the zooids. Some were found in the common tunic enclosed in a membrane

linked to the colony vascular system. Holes at the colony surface provided some

evidence of degenerated zooids, and the larvae in their envelopes seemed to

occupy the spaces vacated by zooids. Only one larva lies in each of these

locations when the zooids produce two eggs. The larvae were not fully

developed and had no vascular ampullae, only the beginning of a tail and one

sensory organ.

Our specimens correspond well with the type material (MNHN BOT. B 14).

Remarks and distribution

We consider this a species of the genus Botryllus, as did Millar (1962), in

view of its parietal budding with early development of the gonad, a

characteristic only encountered in this genus.

SOUTH AFRICAN ASCIDIANS B

In térms of its other characteristics, this species could belong to two other

genera having three longitudinal branchial vessels on each side. In Chorizocarpa

the testis is on the left side, the ovary on the right side, and the budding is

vascular (Monniot, C. 1988). In Botryllocarpa the hermaphroditic gonads are

placed on each side of the body, but the testis is deeply divided into two lobes as

in the genus Symplegma.

Botryllus elegans has unique features for the genus: the absence of systems,

and larvae brooded in the common tunic rather than the zooids. The mode of

development of the larvae also seems different from that described by Zaniolo et

al. (1998) for Botryllus violaceus. The life cycle of this species thus merits

further studies.

The description of Distomus elegans Quoy & Gaimard, 1834, is extremely

short and only provides its external characteristics, but the coloured illustrations

leave no doubt about the species’ identification. The siphons are depicted as

having six lobes, which is not the case in our specimens and this is probably an

error in the illustrations.

Sluiter (1898qa) did not recognize Distomus elegans and created a new

species, Synstyela monocarpa. Hartmeyer (1912) ignored Sluiter’s species and

created yet another species, Chorizocarpa elegans.

Michaelsen (1924), on re-examining Sluiter’s samples, noticed labelling

errors between specimens from South Africa and colonies collected in the north

of Australia that Sluiter (1900) had described under the name Synstyela

michaelseni.

Moreover, other specimens labelled from South Africa were labelled as

Symplegma species. Michaelsen concluded that there were two species in South

Africa: one with four longitudinal vessels that he identified as Symplegma

Fig. 37. Botryllus gregalis. A-B. Both sides of a zooid. C-D. Details of the gut.

74 ANNALS OF THE SOUTH AFRICAN MUSEUM

elegans (Quoy & Gaimard, 1834), and another with three longitudinal vessels

identified as Chorizocarpa monocarpa (Sluiter, 1898a). This last species might

have been confused with Chorizocarpa michaelseni (Sluiter, 1900) from

northern Australia, in view of Sluiter’s labelling errors, and Michaelsen was

surprised by the synonymy considering the distance between the populations. He

suggested that further collections were necessary. He overlooked the fact that,

in 1915, he combined as synonyms Distomus elegans and Synstyela monocarpa.

He thus considered Distomus elegans to be the commonest species of the

genus Symplegma, partly because six oral lobes were figured by Quoy &

Gaimard, and because specimens of Symplegma were mixed with Sluiter’s

specimens.

We similarly found errors in the synonymies of Symplegma brakenhielmi

and Chorizocarpa michaelseni. The synonymies listed above only correspond to

descriptions of specimens and does not take into account more or less erroneous

citations.

Botryllus elegans is known from Namibia to southern Mozambique.

Botryllus gregalis (Sluiter, 1898a)

Figs 4A, 37

Botrylloides gregalis Sluiter, 1898a: 46, pl. 2 (figs 6-9).

Botrylloides nigrum non Herdman, 1886. Hartmeyer, 1912: 270, pl. 41 (fig.10).

Part Botrylloides leachi non Savigny, 1816. Hartmeyer & Michaelsen, 1928: 342.

?Botrylloides leachi: Michaelsen, 1934: 154.

?Botrylloides leachi: Millar, 1962: 177.

Botryllus gregalis: Monniot, C. & Monniot, F., 1997: 1633, text-figs 5-6, pl. 1C, D.

Material

Several specimens. Saldanha Bay, on kelp; False Bay, 8-12 m; Cape Town,

10 m; Isipingo, KwaZulu-Natal (Griffiths coll.); Knysna and Port Elizabeth

(Monniot coll.); Sodwana Bay, KwaZulu-Natal (Schleyer coll.).

Description

The colonies are 2-3 mm thick in this species. The colour varies and the

oral siphons and cloacal languets are generally opaque. The zooids are

distributed along an anastomosed network of cloacal cavities that have few

common cloacal openings.

The zooids have 12-13 rows of stigmata, the second row being dorsally

incomplete on both sides (Fig. 37A, B). The cloacal aperture extends one-third

of the branchial height, under a large cloacal languet. The anterior end of the

stomach (Fig. 37C, D) is wide and has about ten folds, which flare anteriorly

and attenuate posteriorly. The caecum is always small but sometimes enlarged

at the tip (Fig. 37C). A well-developed pyloric gland of joined vesicles

surrounds the intestine like a sleeve (Fig. 37C, D). The rectum is wide and

opens at the eighth or ninth row of stigmata without narrowing.

None of the colonies studied had eggs or embryos. The nourishing zooids

have degenerated testes located posteriorly against the gut (Fig. 37A, B). The

SOUTH AFRICAN ASCIDIANS I

first-order buds have well-developed testes. The ovaries have few oocytes and

develop on the second-order buds.

Remarks and distribution

It is possible that the specimen named Botrylloides leachi by Michaelsen

(1934) belongs to this species, together with the specimens that Millar (1962)

considered doubtful. The specimen described by Hartmeyer (1912) as

Botrylloides nigrum from the Cape Peninsula has exactly the same stomach as

the specimens in our collection, and Michaelsen (1934) expressed doubt as to its

identification.

This polymorphic species has a continuous distribution along the west coast

of South Africa, and extending to the Arabian Gulf.

Botryllus maeandrius (Sluiter, 1898a)

Figs 4B, 38

Botrylloides maeandrium Sluiter, 1898a: 48, pl. 2 (fig. 7), non pl. 6 (fig. 10).

?Botrylloides translucidum Hartmeyer, 1912: 272, pl. 37 (fig. 3), pl. 41 (figs 8-12).

Material

Several colonies; one of them adult, on a Mytilus shell, represents a

neotype, SAM-A25862. Sea Point, intertidal (Griffiths and Monniot coll.).

Description

The colonies are thin and encrusting. The zooids are distributed in double

rows on each side of large, branched cloacal channels. Some zooids are found

in circular systems, but are facing by their ventral part. There are only a few

common cloacal apertures that do not protrude and are hardly visible. The

colonies often have a branched pattern with rows of zooids radiating in all

directions from the colony centre. The edge of the colony is marked with an

accumulation of vascular ampullae. The colour is a uniform pink to reddish-

pink. The pigment cells are more dense around the oral siphons and in the

vascular ampullae. The tunic matrix is colourless. After fixation the pigment

fades and the zooids become brownish.

The zooids have a wide rectangular cloacal languet above a large cloacal

opening that reveals a large part of the branchial sac (Fig. 38A, D). There are

9-10 rows of a dozen stigmata per side and the second row does not reach the

dorsal line (Fig. 38E).

The conical stomach (Fig. 38B) is asymmetrical and dilated with a dozen

anterior folds that are mere protrusions on the left side but become

progressively longer and form folds on the right side (Fig. 38D). The caecum is

a small pedunculate ball (Fig. 38B). The intestine is constricted by a voluminous

pyloric gland that encircles it. The gut loop is well defined. The anus opens in

front of the fifth or sixth row of stigmata and has a curled rim.

Most colonies have no gonads at all. The colonies collected in February

were male or hermaphroditic. In male colonies the testes appear on first-order

buds. In hermaphroditic colonies (Fig. 38A) the zooids have bulky testes with

76 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 38. Botryllus maeandrius. A. Zooid. B. Gut. C. Hermaphroditic gonad.

D-E. Two additional zooids.

less than ten lobes. These protrude slightly to the exterior and are located

almost at the same level in the posterior and ventral part of the body. An ovary

located dorsal to the testis in a pedunculate pouch (Fig. 38A) contains one or

two degenerated eggs.

Remarks

We have re-examined the type of B. maeandrium Sluiter, 1898a (ZMA TU

297). It is not well enough preserved to be redescribed, but does not correspond

either to Sluiter’s description or pl. 6 (fig. 10) of the species. It has no systems

and may either be Botryllus elegans or a species of Symplegma. However,

Sluiter’s (1898a, pl. 2 (fig. 7)) colour drawing corresponds well to the species

described here. His pl. 6 (fig. 10) is surprising; it depicts a zooid with five

longitudinal vessels, a small cloacal aperture, a gut with the structure of a

Botryllus, and gonads with a non-protruding ovary in the position in which it is

found in B. elegans. His zooid description corresponds to this figure. The

labelling of Sluiter’s specimens is often erroneous, as Michaelsen (1924) has

already noted, and it is not rare to find several-species from different families in

one of his type samples. His descriptions sometimes appear to be fanciful if not

totally imaginary.

SOUTH AFRICAN ASCIDIANS HW

We propose to use the name Botryllus maeandrius (Sluiter, 1898a) for

this species to simplify the synonymy, as the original description has no

value and the type specimen has been lost. We have made an adult colony

collected at Sluiter’s type locality, Sea Point (Cape Peninsula), a neotype for the

species.

The description of Botrylloides translucidum Hartmeyer, 1912, corresponds

to this species in some respects, as it describes an ascidian with the same gut

shape, and an elongated stomach with short posterior protruding rods.

However, Hartmeyer’s colonies are 9-mm-thick cushions, with zooids with

12 rows of stigmata and no pyloric caecum. These attributes are characteristic

of Botryllus translucidus, leading us to conclude that it is closely allied to if not

identical with B. gregalis.

Botryllus maeandrius has been recorded only from the Cape Peninsula,

South Africa.

Botryllus magnicoecus (Hartmeyer, 1912)

Figs 4C, 39

Botrylloides nigrum magnicoecum Hartmeyer, 1912: 271, pl. 41 (fig. 11); 1913: 135.

Botryllus magnicoecus: Michaelsen, 1921: 6, pl. 1 (figs 1-4); 1934: 154. Millar, 1955: 195,

hig 22 11962: 175.

Material

Several colonies. Table Bay, 9 m; False Bay, 0-10 m (Griffiths coll.);

Saldanha Bay, Hout Bay Harbour, and Kommetjie intertidal (Monniot coll.).

Description

The flat fleshy crusts of this species may be lobed or hang in double-sided

sheets in harbours. In Hout Bay Harbour, the suspended colonies reach several

decimetres. The oral apertures in almost all colonies are circled with white

pigment, which contrasts with their pink colour. One colony from Miller’s Point

had reddish zooids in a yellow tunic. The zooids are arranged along a network

of cloacal channels. There are only a few common cloacal apertures; they do

not protrude at the colony surface.

The zooids have a cloacal languet of variable size, sometimes very short.

The transverse cloacal opening may reveal half the length of the branchial sac.

There are 12-15 rows of stigmata of which the second does not reach the dorsal

lamina on either side of the body (Fig. 39A). The short oval stomach (Fig. 39B)

bears 8-10 rods without anterior swellings and is well defined at the pyloric

extremity. The caecum is long, cylindrical and often curved in a hook

(Fig. 39B). The pyloric gland is small. The anus when contracted appears

bilobed.

None of our specimens had ovaries or larvae. The nourishing zooids only

had a multi-lobed testis on each side, the right one adjacent to the stomach

(Fig. 39A, C) and the left one more anterior at the level of the intestine. The

first-order buds (Fig. 39C) have testes as large as those of the nourishing

zooids. Ovaries with 1-3 oocytes only appear in buds of the second order.

78 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 39. Botryllus magnicoecus. A. Zooid. B. Gut. C. Buds of first and second orders.

Remarks and distribution

When fixed, the pigments fade and B. magnicoecus becomes similar in

appearance to B. gregalis. The number of stigmata rows and the body shape are

similar. The species only differ in the shape of their stomach and the caecum.

This is probably why Hartmeyer (1912) considered this a variety of his

Botrylloides nigrum, which, in our opinion, is Botryllus gregalis (see p. 74).

The name B. magnicoecus has been used worldwide for all species having a

large caecum. Michaelsen (1923b) recorded this species in Portugal, the Red

Sea, and Hong Kong. Hartmeyer & Michaelsen (1928) increased the confusion

when they included the Australian B. anceps as a synonym.

The geographic distribution of B. magnicoecus in South Africa seems to be

limited to the coast from Namibia to KwaZulu-Natal. All specimens recorded

from other parts of the world, viz. the Mediterranean Sea, Portugal, Caraibes,

Australia and Japan, belong to other species.

Botryllus mortenseni Millar, 1964

Figs 4D, 40

Botryllus mortenseni Millar, 1964: 176, fig. 13.

Material

One large colony and several small ones attached to other ascidians.

Isipingo, KwaZulu-Natal, rock pools (Griffiths coll.).

SOUTH AFRICAN ASCIDIANS 12

COG a

A mM.

Fig. 40. Ata eee eee urishing zooid of the largest c SOR ac ela of first

and second o es of the sai cree eyes agar ng zooid of a small colon ny.

De Gut of z oid C. E. Zoo Stee eta ot yet open area thinratic e gonads, in

other Saisie

80 ANNALS OF THE SOUTH AFRICAN MUSEUM

Description

The largest colony is a cushion 5-6 mm thick, embedded with sand. Its

black colour fades in formalin. The zooids are perpendicular to the colony

surface and organized in circular systems around numerous common cloacal

openings. The zooids are large, 3 mm in length, with a slit-shaped cloacal

aperture and a long anterior conical languet and a posterior lip almost as long as

the languet (Fig. 36A, C). The branchial sac has 12 rows of stigmata, all

reaching the dorsal line (Fig. 36A). On the right side, some perforations

represent a thirteenth row. The stigmata are numerous and there is an average

of three between each internal longitudinal vessel. The stomach is oval, with a

dozen folds that protrude slightly at the anterior end but flatten out at the

posterior. The caecum is long, narrow and cylindrical (Fig. 36D). The

secondary loop of the intestine is not accentuated and the rectum extends along

4-5 rows of stigmata, opening at the level of the eighth row. In the large

colony, the nourishing zooids sometimes have a rudimentary testis. Ovaries

with numerous oocytes appear in second-order buds and are also present in first-

order buds (Fig. 36B).

Small colonies consisting of a single system were found on other ascidians

at the same station. The smaller zooids (Fig. 36C), less than 2 mm long, have

a cloacal aperture shaped like a whistle. There are only 11 complete rows

of stigmata and a beginning of a twelfth row on the right (Fig. 36C).

The nourishing zooids are hermaphroditic with a testis made of elongated

fan-shaped lobes and 1-2 eggs anterior to the testes on each side (Fig. 36C).

We observed a trace of segmentation in these eggs, which do not protrude

outside the body wall. There are 2-3 eggs on each side in first-order buds

(Fig. 36E).

Remarks and distribution

The type specimen of this species was collected 22 miles south-west of Cape

Point at 55 m depth, and it is a little different to the specimens from Isipingo.

The colony is thicker (15 mm) and the zooids are longer (4-5 mm). The scale

included in Millar (1964, fig. 13) is probably erroneous and may correspond to

1 mm. The oral siphon is tubular. There are 16-18 rows of stigmata. Both of

Millar’s other specimens were dredged from Mossel Bay at 16 m depth, and

have shorter and wider cloacal siphons than in our specimens.

We consider that the colonies collected at low tide at Isipingo belong to this

species in spite of these differences. Botryllus species are relatively variable

according to colony thickness. In Europe, we have observed that the zooids of

B. leachi and B. schlosseri are larger and have more rows of stigmata in

spherical colonies than in encrusting colonies. This was the reason that the now

abandoned genera Polycyclus and Sarcobotrylloides were created for thick

colonies. The length of the cloacal siphons is related to the distance between the

zooid and the common cloacal aperture, and thus the age of the system and the

position of the bud.

The small colonies at Isipingo were sexually mature whereas the larger ones

were not. This phenomenon may be linked to ecological difficulties encountered

by the small colonies, which react by maturing gonads.

SOUTH AFRICAN ASCIDIANS 81

Three other species of Botryllus impregnated with sand are known from

elsewhere. They are closely allied and have in common a thick tunic, circular

systems, zooids perpendicular to the colony surface, a whistle-shaped cloacal

siphon placed anteriorly and sometimes in a tube, a branchial sac with an entire

second stigmata row, and an ovary anterior to the testis with several eggs.

Botryllus stewartensis Brewin, 1958, from the south of New Zealand and

Australia (Kott 1985) has small pedunculate lobes, distantly spaced, consisting

of 1-3 systems. The stomach is oval with a long caecum. The testis is

fan-shaped.

Botryllus arenaceus Monniot, C., 1988, from New Caledonia has lobes with

a single system, a wide stomach with protruding folds at its anterior part, a

caecum with an ampullae at the tip, and a mulberry-shaped testis.

Botryllus okai Monniot, C., 1988 (new name for the preoccupied

Psammobotrus purpureus Oka, 1932), from Japan, has massive colonies with

numerous systems. The stomach is similar to that of B. mortenseni, but has an

ampullar caecum and an anus with a curled margin. The gonads have not been

described and were only present in buds in specimens that we examined. The

testis has elongated lobes.

Botryllus schlosseri (Palas, 1766)

Alcyonium schlosseri Pallas, 1766: 355.

Remarks

We have only collected this species in harbours, in Saldanha Bay and Hout

Bay. The colonies are small, thin and encrusting. The zooids form circular

systems. Live specimens are a green-brown colour. None of these colonies had

gonads. This species has been previously recorded in South Africa, from

Durban Harbour (Millar 1955).

Symplegma ?bahraini Monniot, C. & Monniot, F., 1997

Fig. 4E

Symplegma bahraini Monniot, C. & Monniot, F., 1997: 1638, text-fig. 7, pl. 1E, F.

2Symplegma viride: Millar, 1955: 196, fig. 24.

Material

Three colonies. Sodwana Bay, KwaZulu-Natal, 30-33 m (Schleyer coll.);

Isipingo, KwaZulu-Natal, rock pool under overhang (Griffiths coll.).

Description

None of our three colonies has gonads, so the identification could not be

made with certainty. An important characteristic of the species is the

simultaneous presence of functional male and female gonads.

The uniform red colour of the colony from Isipingo was the same as in the

type colony (Monniot, C. & Monniot, F. 1997, pl. 1E). The colonies from

Sodwana Bay were pink-brown, with yellow individuals. Another colony from

82 ANNALS OF THE SOUTH AFRICAN MUSEUM

Bahrain also was yellow in colour. Yellow samples were also collected in the

Mozambique Channel, at Juan de Nova Island and in the north of Mozambique.

The samples from South Africa have a short gut and a branchial sac with

11 stigmata rows, as in the Bahrain specimens.

Remarks and distribution

Millar (1955) recorded the presence of S. viride in the Durban Harbour

entrance but did not describe it. Millar referred to Van Name’s (1945)

description, which in reality represents §. brakenhielmi (Michaelsen, 1904b).

The latter has been found in many harbours in the Atlantic Ocean, Australia,

and the Pacific Ocean (often under the name S. oceania). Symplegma

brakenhielmi does possibly occur in Durban Harbour. That species differs from

S. bahraini in that its pigmentation is limited to the branchial vessels. When

fixed all colour disappears, which is what Millar saw.

Metandrocarpa asymmetra C. Monniot sp. nov.

Fig. 41

Material ,

Holotype. SAM-A25857, Oudekraal, Cape Peninsula (33°59’S 18°21’E),

10 m depth on Styela angularis. Collected by C. L. Griffiths, 18 Aug. 1994.

Unique.

Description

The colony consists of zooids at different developmental stages, all having

female gonads. The zooids form small pink spheres, 4 mm in diameter, linked

by very thin stolons, with closely spaced siphons. The tunic is thin. The

translucent body wall contains weak musculature.

Twenty to 24 short thick oral tentacles in 3-4 orders of size are mounted on

a crest (Fig. 41A, B). The prepharyngeal band has only one protruding edge

which is not dorsally indented (Fig. 41A, B). The dorsal tubercle protrudes and

has an elongated opening next to the neural ganglion. The dorsal lamina has a

smooth edge that is displaced on the left side and turns around the oesophagus

entrance.

The branchial sac is asymmetrical, hence the species name. It has seven

longitudinal vessels on the right but only four on the left side. The 11 stigmata

rows are each crossed by a thin parastigmatic vessel, except for the most

posterior row. The stigmata are regularly spaced. Their number is indicated in

the formula:

R.E.8v4vov4v4v4v4v4tolISDL5sv8v7v9VI2ZELL.

In the anterior part of the branchial sac, the number of stigmata is the same

on both sides. The first vessel deviates from the dorsal lamina and we found up

to 15 stigmata at the level of the oesophagus.

The oesophagus is long and cylindrical, the stomach is wider than it is long

(Fig. 41A, B) with 14 folds that are sometimes interrupted. The caecum forms a

thin hook (Fig. 41C). The pyloric gland opens through a duct just before the

SOUTH AFRICAN ASCIDIANS 83

Fig. 41. Metandrocarpa asymmetra. A. Young zooid with ovaries on both body sides.

B. Aged zooid with gonads on one side only. C. Stomach. D. Detail of the gonads.

E. Larva.

caecum (Fig. 41A, B). The intestine ends in a slightly narrowed rectum. When

contracted the anus is square, but it lacks angles when relaxed.

Ten to eleven ovaries lie in a line on the right side of the body (Fig. 41B),

and one, two or three ovaries are found on the left side of the body, anterior to

84 ANNALS OF THE SOUTH AFRICAN MUSEUM

the gut loop (Fig. 41A). Each ovary is made of a few oocytes and a large papilla

(Fig. 41D). The papilla is narrow at first but becomes thick with a fleshy rim

when the eggs are laid (Fig. 41D). The larvae (Fig. 41E) are brooded in a cup

formed from the external egg follicle; this structure remains behind when the

larvae are released. There are some endocarps on the body wall. A ring of

small tentacles encircles the base of the cloacal siphon (Fig. 41A, B). Both

siphons possess a velum.

Remarks

The genus Metandrocarpa is characterized by separate male and female

gonads and the absence of branchial folds. Kott (1985) modified the diagnosis to

include M. agitata Kott, 1985, which possesses true branchial folds. We do not

agree with this modification, as it suppresses the difference between the genera

Amphicarpa and Metandrocarpa. Metandrocarpa agitata is in fact an

Amphicarpa. Generally the Metandrocarpa species have male and female

gonads in the same colony. Metandrocarpa sterreri Monniot, C., 1972, from

Bermuda and the Caribbean islands, also has dioecious colonies.

Metandrocarpa asymmetra is also original in the asymmetry of the branchial

sac. Millar (1962) described M. fascicularis from Mossel Bay. That resembles

M. asymmetra superficially, but the species are distinct. Metandrocarpa

fascicularis has 7-9 longitudinal vessels on each side depending on its age, an

elongated stomach, anterior ovaries and posterior testes.

Distomus antiborealis C. Monniot sp. nov.

Fig. 42

Material

Holotype. SAM-A25858, Saldanha Bay (33°03’S 18°02’E), 1-2 m depth.

Collected by C. and F. Monniot, Feb. 1996. Unique.

Description

The zooids are in the shape of small spheres, 10 mm in diameter and

covered with sand. The siphons are close together. The tunic is tough. The body

wall is thin but opaque with a regularly distributed musculature. Sixteen wide

and thick oral tentacles form a crown at the base of the siphon. Some smaller

tentacles are irregularly intercalated between them. The prepharyngeal! band has

only one high rim and it forms a short dorsal indentation. The dorsal tubercle is

protruding and opens through an antero-posterior slit. The dorsal lamina is high,

with a smooth edge; it ends mid-length along the oesophagus entrance. The

endostyle is not fully attached to the body wall but only connected to it by thin

trabeculae.

The reduced branchial sac has one fold on the right and two on the left side.

The first fold on the left side is reduced and limited to the anterior part of the

branchial sac. We counted ten vessels anteriorly on each side, arranged

according to the formula:

R. E.5 (4) 1D.L. (3) 2 G)2E. L.

SOUTH AFRICAN ASCIDIANS 85

Fig. 42. Distomus antiborealis sp. nov. A. Zooid with reversed gut. B. Gut.

C. Young ovaries. D. Young testes.

The most dorsal vessel on the right fold and the three vessels of the first left

fold disappear in the median part of the branchial sac. There is a large space

between the dorsal lamina and the first vessel, containing up to 16 stigmata on

the right side. There are 7-9 stigmata in a mesh between the folds and two on

the folds. The 14 rows of long stigmata are crossed by parastigmatic vessels

only in the ventral part.

The oval stomach has a hook-like caecum and about 20 oblique grooves,

most of them ending at the ventral axis of the stomach (Fig. 42A, B). The

intestine is short. The rectum ends in a smooth-edged anus far from the cloacal

aperture.

86 ANNALS OF THE SOUTH AFRICAN MUSEUM

The zooids are not mature, but the gonads are developed enough to

characterize the genus. Eight ovaries with several oocytes (Fig. 42C) lie ina

line on the right side (Fig. 42A) alongside the trabeculae between the endostyle

and the body wall. The oviducts are directed toward the dorsal side. The testes

(Fig. 42D) are functional, in small flask-shaped ampullae. They are irregularly

distributed on the left side along a line curving posteriorly (Fig. 42A). Some

testes are located under the gut.

Numerous endocarps of varied sizes are present on the body wall. The

cloacal tentacles are short, thin and numerous.

Remarks and distribution

Distomus antiborealis is the first species of Distomus recorded in southern

Africa. The genus is more frequently encountered along the Atlantic coast from

Senegal to the North Sea and in the Mediterranean Sea. One species inhabits

deep submarine mounts in the south of New Caledonia.

The genus Distomus is related to the genera Amphicarpa and Stolonica. It is

only characterized by female gonads on the right side of the body and male

gonads on the left side of the body. In other species of the genus the testes are

less numerous and larger. Their presentation here is reminiscent of the genus

Amphicarpa.

Stolonica multitestis C. Monniot sp. nov.

Figs 4F, 43

Material

Holotype. SAM-A25859, Isipingo, KwaZulu-Natal (30°00’S 30°57’E), in

rock pools. Collected by C. L. Griffiths, 10 July 1994. Unique.

Description

The zooids are joined only in the basal region by stolons and form sheets

10 mm thick. The oral siphon is terminal, the smaller cloacal siphon more

lateral. The thin tunic includes some sediment. In life the tunic is orange-red

with, between the siphons, two symmetrical white patches separated by an

unpigmented area corresponding to the neural ganglion.

The body wall is transparent with a thin musculature. We counted about

30 stout oral tentacles joined at their wide bases, in several orders, but not very

different in length. There are some others between them, variable in size but

much smaller. The tentacles lie on a muscular ring. The prepharyngeal band has

two high closely spaced membranes drawing a small dorsal curve. The dorsal

tubercle protrudes slightly and is transversely elongated near the neural

ganglion. The dorsal lamina is long, thin, low, and encircles the oesophagus

entrance. The branchial sac has three folds on the right side and two folds on

the left side. In the anterior part we counted:

R.E. 3(4) 2(5) 3(5) 3 D.L. 0(6) 3(6) 8 E.L.

The only folds to reach the oesophagus entrance are the first fold on the

right and the second fold on the left. The most dorsal vessels disappear in the

SOUTH AFRICAN ASCIDIANS 87

Fig. 43. Stolonica multitestis sp. nov. A. Ventral side of a zooid. B. Internal side of a

zooid. C. Gastric caecum and pyloric duct. D. Right gonads. E. First stage of left gonads.

F. Right gonad at the same stage as E, same scale.

posterior part of the branchial sac. On the left side, the first fold is parallel to

the dorsal lamina.

On the right side, the first three longitudinal vessels are parallel to the dorsal

lamina and three additional vessels appear successively between vessel

number 3 and the base of the first fold. There are thus six vessels between the

dorsal lamina and the first fold in the posterior part of the branchial sac. In

some zooids there is a rudiment of a third fold on the anterior left side due to

two incomplete vessels arising dorsal to the third vessel from the endostyle.

Of the 16 rows of stigmata, the most anterior 14 are regularly cut by a

parastigmatic vessel, the fifteenth is incompletely divided, and the last one is

irregular. There are 6-7 long stigmata within a mesh and three under the folds.

The stomach (Fig. 43B, C) widens at the pyloric end. There are about

35 regular parallel grooves and a small finger-like caecum. The duct of the

pyloric gland is conspicuous and enters the caecum (Fig. 43C). The long rectum

ends in a gaping anus.

The gonads lie in a row on each side of the ventral line (Fig. 43A). A row

of flasked-shaped testes, of variable size (Fig. 43B), is not always well aligned

88 ANNALS OF THE SOUTH AFRICAN MUSEUM

on the left side. On the right, there are testes in the anterior, hermaphroditic

gonads at the level of the gut, and some testes in the extreme posterior

(Fig. 43B). The number of hermaphroditic gonads varies between zooids. The

colonies are not fully mature, and are not brooding larvae. In young specimens,

the progressive gonadal development can be observed (Fig. 43D-F) on both

sides of the body, each gonad lobe consisting of two vesicles with a single

aperture (Fig. 43E, F). The posterior vesicle regresses rapidly on the left side,

while it develops into the ovary on the right side (Fig. 43F). We did not observe

oviduct formation.

There are few endocarps and no cloacal tentacles.

Remarks and distribution

Stolonica as a genus sensu stricto forms an homogeneous group. Stolonica

multitestis sp. nov. is the first species of the genus collected in South Africa.

The South African species is characterized by unlobed testes, a stomach slightly

elongated, and a large number of testes on the left side with short ducts.

Gynandrocarpa placenta (Herdman, 1886)

Figs 4G, 44

Goodsiria placenta Herdman, 1886: 328, pl. 43 (figs 1-10), pl. 44 (figs 4, 8-10).

Goodsiria placenta fusca Herdman, 1886: 326, pl. 44 (figs 5-7).

Gynandrocarpa placenta unilateralis Michaelsen, 1900: 29.

Gynandrocarpa placenta fusca: Michaelsen, 1900: 29.

Gynandrocarpa domuncula Michaelsen, 1902 (nomen nudum); 1904a: 247, pl. 11 (fig. 14),

pl. 13 (fig. 58).

Gynandrocarpa unilateralis: Millar, 1962: 178, fig. 27; 1964: 166.

non Polyandrocarpa placenta: Millar, 1955: 199, fig. 26 (= Polyandrocarpa sp.)

Material

Two colonies, Miller’s Point, False Bay, 15 m depth; Oudekraal, 6 m depth

(Griffiths coll.).

Description

This abundant species has the characteristic shape of an ‘elephant ear’. It

has a double layer of zooids held erect on a short peduncle of massive tunic

tissue. Among colonial styelid species, pedunculate ones are the less common.

The zooids are pink in life and three-quarters of their length is enclosed in a

thick fibrous tunic. The zooids (Fig. 44A, B, C) are 6-8 mm long and enclosed

in a tunic capsule. The siphons are close together. The body wall is thin with

muscles regularly distributed over the entire body. Pigment flecks are found

everywhere. There are 20-40 stout, curved oral tentacles arranged irregularly

in 3-4 orders. The prepharyngeal band has two parallel rims and forms a low

dorsal ‘V’. The dorsal tubercle is button-shaped and opens in a simple hole. The

dorsal lamina is high but rather short. The endostyle does not extend beyond the

postero-ventral side of the body and turns into a long retropharyngeal band

where most of the longitudinal vessels end. The oesophagus entrance is two-

thirds of the way down the branchial sac.

SOUTH AFRICAN ASCIDIANS 89

Fig. 44. Gynandrocarpa placenta. A. Left side of a zooid. B. Right side of a zooid.

C. Zooid opened along the ventral line. D. Stomach. E. Gonad with the oviduct leading

into the incubatory pouch.

The branchial sac has three folds on each side. The third fold on the left side

is always smaller than the others, variable between the individuals, and does not

reach the posterior part of the branchial sac. The branchial formula is:

Ree (4).31©) 6:6) 1 DEL. 2 (6) 3 6) 3.2) 2 E..L:

The first vessel on the left side remains parallel with the dorsal lamina down

to the oesophagus entrance. The stigmata are short and without parastigmatic

vessels. There are, on average, five stigmata in a mesh between the folds and

2-3 on the folds.

The gut (Fig. 44C, D) is linked to the body wall only by trabeculae. The

ovoid stomach has about 20 longitudinal grooves. The caecum (Fig. 44D) is

hook-shaped and arises at a point two-thirds down the stomach. The secondary

intestinal curve is not accentuated. The rectum is long; the anus has four lobes

or a plain edge.

90 ANNALS OF THE SOUTH AFRICAN MUSEUM

The gonad (Fig. 44E) is characteristic of the genus. It lies at the bottom of

the cloacal cavity on the left side of the body (Fig. 44B) and is partially

enclosed in the body wall. The ovary is centrally placed between two long testis

masses. The sperm ducts join to form a very long papilla ending in an ampulla

(Fig. 44).

The oviduct opens against a peculiar structure of the branchial tissue

forming an incubatory pouch (Fig. 44E). This pouch is hemispherical and opens

between two longitudinal vessels. No larvae are present in the colonies. The

body wall bears large endocarps. About 15 cloacal tentacles are particularly

long.

Remarks

Sometimes a dromiid crab digs its hole in the peduncle of the colony and

then carries it on its carapace like a ‘cloak’. It would be interesting to know at

which stage of development this association begins, and whether the crab

removes a piece from a mature colony or a young colony from the substratum to

clothe itself.

The nomenclature for this species is complex. We have examined the type

specimen from the British Museum. Herdman (1886) described the species from

Simon’s Bay. The single gonad is precisely figured in his cross-section figure

(pl. 44 (figs 4, 8, 9)) but in the text Herdman used the plural when referring to

the gonads and this has caused numerous confusions. He did not mention that

the gonad lies on the right side of the body. Herdman also described the variety

G. placenta fusca in the same publication. It only differs in the shape of the

colony, which is less elongated and wider than in the type specimen.

Michaelsen (1900) redescribed the type and created the genus Gynandro-

carpa based on the gonad disposition. He recognized Herdman’s variety

G. placenta fusca and designated Gynandrocarpa placenta unilateralis as the

type of the species.

Stebbing (1902: 26) found colonies associated with Dromiidae and correctly

identified them as Goodsiria placenta.

Michaelsen (1902), in a publication about symbiosis, cited Stebbing’s

specimens under the name Gynandrocarpa domuncula, nomen nudum, a name

that he formally created later (1904a: 247, pl. 10 (fig. 14), pl. 13 (fig. 58)). He

recorded this species from the Agulhas Bank at 100 m depth and from Dar es

Salaam at 400 m. The same year, Michaelsen (19045) described Gynandrocarpa

placenta and Gynandrocarpa domuncula, differing in colony shape only, one of

them being free-living on the bottom, the other settling on a crab. He abandoned

the distinction between G. placenta fusca and G. placenta unilateralis. In an

appendix to the same paper (p. 114) he noted the presence of this species in

KwaZulu-Natal.

Herdman (1912) recorded Goodsiria (Gynandrocarpa) placenta from the

Falkland Islands without giving further details.

Millar (1955) upset everything by describing a true Polyandrocarpa that he

named Polyandrocarpa placenta. In 1962, having found the ‘elephant ear’, he

referred it to Gynandrocarpa unilateralis Michaelsen, 1900, and compiled the

correct description of Herdman’s species.

SOUTH AFRICAN ASCIDIANS 91

Kott (1969) assigned the name Polyandrocarpa placenta sensu Millar (1955)

to Herdman’s specimens from the Falkland Islands without seeing the

specimens.

We have not been able to find Millar’s specimens (1955) in museums;

apparently they correspond to a new species.

Remarks on the genus Dextrocarpa Millar, 1955

In 1955, Millar described the genus Dextrocarpa, which has a gonad

similar to that of Gynandrocarpa. He considered (p. 203) that the genus

Dextrocarpa issued from the genus Gynandrocarpa by the ‘loss of budding

power and may be regarded as one of the most specialized genera of the

Polyzoinae’ :

Later (1962, 1988) he found aggregated zooids and assumed that they were

budding.

Another species of the genus, always solitary, was recorded at Kerguelen

(Monniot, C. 1978). More recent data about the budding of colonial Styelidae

and the possible existence of budding in the genus Polycarpa, are persuasive

evidence that Dextrocarpa is a synonym of Gynandrocarpa.

Polyandrocarpa griffithsi C. Monniot sp. nov.

Fig. 45

Material

Holotype. SAM-A25860, Isipingo, KwaZulu-Natal (30°00’S 30°57’E),

from rock pools. Collected by C. L. Griffiths, 10 July 1996. Unique.

Description

Live specimens are reddish and entirely covered with sand, making compact

blocks to which many other ascidians, such as Polyclinum, Molgula and

Botryllus gregalis are attached. The tunic is embedded with sand and thus stiff

and brittle. It is possible to separate the individuals almost to their base. They

vary in size within a block. The reflex tunic within the long protruding siphons

is not coloured.

The body wall is thin, translucent (Fig. 45A, B) and easily torn.

Musculature is limited to the siphons. Both siphons have a large velum. About

60 short and flat oral tentacles, in three orders, arise from a protruding crest.

There is a large space between the tentacles and the prepharyngeal band. The

latter has only one high rim, with a slight dorsal curve. The protruding dorsal

tubercle varies in shape, forming either a ‘C’ that opens to the anterior or a slit

with a variable opening (Fig. 45D). The dorsal lamina is shorter than the

endostyle, and rises progressively higher to end abruptly adjacent to the first

branchial fold on the left at the oesophageal entrance.

The thin branchial sac has four folds on each side. Anteriorly we counted:

R. E. 6 (10) 5 (10) 4 (12) 3 10) 2 D. L. 2 10) 3 12) 410) 5 QO) 1 E. L.

O72 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 45. Polyandrocarpa griffithsi sp. nov. A-B. Both sides of a zooid. C. Zooid opened

along the ventral line. D. Dorsal tubercle. E. Internal side of a mature gonad. F. External

side of a gonad. G. Young gonad with a large central gland.

SOUTH AFRICAN ASCIDIANS 93

The first fold on the right moves away posteriorly from the dorsal lamina.

The first longitudinal vessel on the right side runs parallel to the dorsal lamina;

in the posterior part 3-4 intercalated vessels arise between the first vessel and

the first fold. The folds are sharply cut at the oesophagus entrance. There are

4-5 elongated stigmata in a mesh between the folds, and 2-3 on the folds. They

are regularly crossed by parastigmatic vessels.

The digestive tract is short and has no secondary curve (Fig. 45B, C). The

oval stomach has about 20 grooves, many of them ending at the ventral midline

of the stomach. The anus has a plain edge or four low lobes.

The gonads, arranged in a row on each side of the endostyle (Fig. 45A-C),

have a peculiar structure. They are enclosed in hollows in the body wall. In

each polycarp the ovary lies over the testis lobes (Fig. 45E, F). The oocytes

have a thick layer of clear follicular cells. The oviduct is short and wide. The

ducts of the testis follicles join to form a protruding papilla (Fig. 45E). There is

a round mass of clear tissue above each polycarp that is not related to the gonad

ducts (Fig. 45C, E, G). Its role is unknown. A similar structure has only been

found in Polyandrocarpa glandulosa Monniot, C., 1987, from New Caledonia.

This tissue appears as soon as the gonads deveiop (Fig. 45G).

There are no endocarps. The cloacal tentacles are arranged in a ring at the

base of the siphon.

Remarks

This species could possibly be confused with Polycarpa anguinea or

Polyandrocarpa anguinea (Sluiter, 1898a), recorded from Knysna but not found

during this collection. In both cases, the agglomerated zooids are covered with

sand and their tunics are fused. The siphons are long and the body wall is thin

without endocarps. The gut has an oval stomach and forms an open loop. The

gonads alone are different.

We have examined the type specimen of Polycarpa anguinea in which the

gonads are poorly developed. They are elongated polycarps that protrude into

the cloacal cavity without any evidence of a central vesicle. Samples of

Polycarpa anguinea according to Millar (1955) and of Polyandrocarpa

anguinea according to Millar (1962) probably belong to Sluiter’s species, as

Millar’s illustrations suggest.

Polycarpa insulsa (Sluiter, 1898)

Figs 4H, 46

Styela (Polycarpa) insulsa Sluiter, 1898b: 14, pl. 3 (fig. 43).

Synonymy and distribution see Monniot, C., 1987: 296, fig. 9.

Material

One specimen. Isipingo, in rock pools (Griffiths coll.).

Description

This species is covered with algae and sponges. Some sand is embedded in

the tunic. Live specimens have eight white bands in the interior of both siphons

94 ANNALS OF THE SOUTH AFRICAN MUSEUM

which disappear after preservation. When fixed the cloacal siphon becomes

reddish with eight black external bands that do not exist on the oral siphon. The

tunic is hard and about 1 mm thick.

Fig. 46. Polycarpa insulsa. Internal anatomy.

The body wall is thick and opaque. About 50 oral tentacles are arranged

in no clear order and with some smaller ones between them. The prepharyngeal

band has two rims and a pronounced dorsal indentation. It is prolonged by a

small groove (Fig. 46). The dorsal tubercle is large, protruberant, and opens as

a ‘U’ with the sides curved to the exterior (Fig. 46). The dorsal lamina is long

and low.

The branchial sac has four low folds on each side that do not cover each

other. The branchial formula is:

SOUTH AFRICAN ASCIDIANS 95

Rae. 2(10).3 (14) 3:3) 2 @0)2 D. Lb. 1:14) 4 01) 43) 3 (8) 2 E..L.

The exterior of the branchial sac is lined with fibrous tissue. The first vessel

on the right side runs parallel to the dorsal lamina. The vessels are tightly

compressed on to the folds.

The gut begins in the posterior part of the branchial sac. The enlarged

stomach is long and has no obvious grooves. There is no caecum. The long

rectum has a large diameter and ends with an anus that has two slightly

undulated lobes.

The body wall is lined with a layer of fibrous and resistant tissue in which

the protruding polycarps are wrapped. The polycarps are so close to each other

that they seem attached to each other (Fig. 46). The genital ducts are short.

There are numerous endocarps covering the whole surface of the body wall

(Fig. 46). They are thin and brittle and not covered by the fibrous layer that

they cross through small openings. There are very few, rather stout, cloacal

tentacles arranged in a circle.

Remarks and distribution

Polycarpa insulsa is often characterized by black stripes on the exterior side

of the siphons, but its most peculiar feature is the presence of a layer of

extremely resistant, whitish, fibrous tissue that covers the internal body wall and

extends slightly on to the exterior of the branchial sac. The specimen from

Isipingo is very similar to samples from Martinique and New Caledonia. Small

differences, such as the greater length of the intestine, may be due to the

disposition of the animal on the substratum.

Polycarpa insulsa is widely distributed, extending from the western tropical

Atlantic Ocean to KwaZulu-Natal, and New Caledonia.

Polycarpa mytiligera (Savigny, 1816)

Fig. 47A

Cynthia mytiligera Savigny, 1816: 98, pl. 8 (fig. 2).

For synonymy and distribution see Polycarpa mytiligera: Monniot, F. & Monniot, C., 1999:

29, text-fig. 17, pl. 3F. Additional synonymy: Polycarpa seychellensis: Monniot, C. &

Monniot, F., 1976: 373, fig. 3A.

Material

Three specimens. Sodwana Bay, 15-35 m (Schleyer coll.).

Description

This large species may reach 100 mm across. It is characterized by a dorsal

tubercle with numerous openings, at least in older specimens. There are four

branchial folds on each side and the first on the right side runs parallel to the

dorsal lamina. The gut occupies the posterior third of the body (Fig. 47A). The

stomach is oval, has internal folds, and lacks a caecum. The wide anus has a

Slightly dented margin. About 100 gonads are irregularly distributed on the

body wall (Fig. 47A). This species is rarely found with active gonads and, even

when these are functional, they never protrude but remain hidden in the body

96 ANNALS OF THE SOUTH AFRICAN MUSEUM

wall. The cloacal siphon is encircled by fleshy crests and a row of very small

cloacal tentacles.

Remarks and distribution

This species is abundant along the coasts of the Red Sea, Tanzania and

Mozambique. It has affinities with a large group of tropical species that have

gonads embedded in the body wall and bear endocarps only in the digestive

loop.

Polycarpa rubida (Sluiter, 1898a)

Fig. 47B

Styela (Polycarpa) rubida Sluiter, 1898a: 53, pl. 7 (figs 1-4).

Polycarpa rubida: Millar, 1961: 11; 1988: 836. Monniot, C. & Monniot, F., 1976: 376,

fig. 4.

Material

Several specimens, Sodwana Bay, KwaZulu-Natal, 15-21 an (Schleyer

coll.).

Description

This species is colloquially named ‘the bloody tunicate’ as it grows in

irregular red masses. One finds among them individuals of all sizes from young

buds to mature adults and pieces of wrinkled, hard tunic, the sole remnants of

old specimens that have entirely regressed. The tunic is common to the whole

mass. The zooids are either totally enclosed, with only the siphons protruding,

or they are merely joined at their base, forming a small peduncle above a tunic

mass. All levels of attachment may be observed in a single sample. The tunic is

thick and leathery.

The body wall is opaque and has evenly distributed musculature. Both

siphons possess a large velum. About 50 long, thin oral tentacles are arranged

in 4-5 orders, and occasionally there are smaller ones between them. The

prepharyngeal band has two rims forming a pronounced dorsal curve. The

dorsal tubercle protrudes and occupies the whole dorsal curve. Its opening is

variable in shape but usually S-shaped. The long dorsal lamina ends at the

middle of the entrance to the oesophagus.

The branchial sac has four folds on each side:

R.E. 2 (11) 3 i6) 3 (15).7 G6) DL. 1 (12):3 15) 3 ds) 32

The first longitudinal vessel lies parallel to the dorsal lamina. There are 6-8

elongated stigmata in a mesh between the folds and 2-4 on the folds. They are

often cut by parastigmatic vessels.

The digestive tract has a secondary curve that is only slightly pronounced

(Fig. 47B). The stomach is spindle-shaped and has a thin wall with grooves,

which are sometimes more pronounced at the anterior. There is no caecum. The

intestine ends in a petal-edged anus.

There is one row of gonads in a semi-circle around the cloacal siphon

(Fig. 47B). Each gonad is slightly elongated and protrudes into the cloacal

SOUTH AFRICAN ASCIDIANS O7

Fig. 47. A. Polycarpa mytiligera. B. Polycarpa rubida. C. Cnemidocarpa humilis.

cavity, but remains attached to the body wall along much of its length. The

gonads were inactive in specimens collected in January and May.

Numerous endocarps are distributed over the entire body wall and between

the two limbs of the gut (Fig. 47B). The cloacal tentacles arise from the velum.

There is a compact mass of undifferentiated tissue behind the gut that is used

for regeneration and budding.

Remarks and distribution

It is with much hesitation that we ascribe this species to the genus

Polycarpa, in spite of its colonial aspect. This species is mainly known from

solitary individuals. It belongs to a species group that manifests regeneration

and budding: Polycarpa captiosa (Sluiter, 1885), P. papillata (Sluiter, 1885),

P. olitoria (Sluiter, 1890), and P. madagascariensis Michaelsen, 1912.

98 ANNALS OF THE SOUTH AFRICAN MUSEUM

These species are characterized by closely spaced siphons, elongated gonads

in a single row within the middle of the body wall, numerous endocarps, and a

gut loosely attached to the body wall with a clearly striated stomach. All the

species have the ability to shed and regenerate the branchial sac and gut. This

phenomenon is more or less pronounced according to the species, from an

accidental to obligatory evisceration. Generally, these species are only able to

develop gonads after evisceration. After a zooid releases its genital products, it

regenerates either into a new zooid or into several more or less separate cloned

zooids, as in P. papillata, or an aggregation of cloned zooids, as in P. rubida.

No specimens with mature gonads were recorded in P. rubida and few in

other species of the same group.

Polycarpa rubida has been recorded from Mozambique to KwaZulu-Natal.

Cnemidocarpa humilis (Heller, 1878)

Fig. 47C

Styela humilis Heller, 1878: 26.

For synonymy and distribution see Asterocarpa humilis in Kott, 1985: 141, fig. 65.

Material

Several specimens. Hout Bay Harbour, on ropes (Monniot coll.).

Description

The specimens are globular and attached to the substratum on their posterior

left side. The siphons are slightly protruding and circled by papillae. When

contracted, the siphons retract deeper than the papillae. The tunic is thin, soft

but resistant. The largest individuals (60 mm) are covered with various

epibionts, including even mussels.

Young specimens are slightly translucent and pink. Internal muscles are

visible through their body wall and so is the diffuse circular musculature issuing

in radial ribbons from both siphons. About 40 irregularly developed oral

tentacles are distributed in four orders on a muscular rod. In one specimen,

parasitic ciliates caused a ramification of the tentacles. Only a few of these

ramifications have ciliates on their tips. The prepharyngeal band has two rims,

the anterior one being irregular and the posterior more developed. There is a

deep dorsal indentation without scalloping at the level of the branchial folds

(Fig. 47C). The dorsal tubercle is a protruding button, open at the anterior in a

simple ‘C’ in young individuals but having a double spiral rolled to the exterior

side in old specimens. A plain dorsal lamina progressively tapers and ends at

the oesophagus entrance. The endostyle is attached to the body wall by a raised

and thin membrane or long trabeculae.

The thin branchial sac has four low folds per side. It is linked to the body

wall by particularly numerous dermato-branchial bridges. We counted:

R.E. 4 (7) 3 (8) 3 (8) 3 (8) 0 D.L. 0 (9) 3 (8) 3 (6) 3 (5) E.L.

There is no sinus between the dorsal lamina and the first folds. There are

15-20 stigmata in a mesh between the folds and 3-10 on the folds. The stigmata

are small and often intersected by parastigmatic vessels.

SOUTH AFRICAN ASCIDIANS 99

The stomach is dilated and soft with some internal grooves. There is no

caecum. The intestinal wall is transparent and has a well-marked typhlosole.

The horseshoe-shaped anus has a curled rim. The gut is surrounded by

endocarps (Fig. 47C).

In young individuals the gonads are well separated with 4-6 on the right

side and two on the left side. The gonads become ramified during growth and

join to form a single mass (Fig. 47C) crossing the line of the endostyle. The

number of sperm ducts increases as the gonads develop, opening through large

papillae scattered over the gonads. The oviducts are less numerous and hardly

visible.

Remarks and distribution

Kott (1985) illustrated Australian specimens as having ramified gonads that

remained independent from each other. The samples from the Magellanic region

have united gonads, as in the present collection. All other characteristics, the

branchial sac, the gut, and the endocarp disposition, are identical. This species

is Common in natural habitats in New Zealand, southern Australia and the

southern end of South America. It is surprising that a species of such large size

has only been collected in harbours in South Africa. It may have been

introduced.

Styela angularis (Stimpson, 1855)

Fig. 48

Cynthia angularis Stimpson, 1855: 387.

Tethyum costatum Hartmeyer, 1911: 564, pl. 47 (fig. 8), pl. 57 (figs 11-12).

Styela costata: Hartmeyer, 1913: 133. Michaelsen, 1915: 379. Millar, 1955: 204, fig. 29.

Styela angularis: Hartmeyer, 1927: 189. Millar, 1962: 190; 1964: 175.

Material

Several specimens, Oudekraal, Cape Peninsula, 10 m (Griffiths coll.).

Description

This pedunculate species has a characteristic hexagonal cross-section; it can

exceed 100 mm in height. The cloacal siphon is terminal and the oral siphon

opens a short distance to the ventro-posterior. Both have four lobes. The stiff

tunic is often covered with epibionts, among them ascidians. The body without

the tunic is cylindrical. The body wall is opaque and contains a strong

musculature. A bunch of vascular processes emerges at the body extremity and

enters the peduncle (Fig. 48). The body wall is not prolonged into the peduncle.

There are about 60 oral tentacles that alternate in four orders of size, those of

the fourth order being of variable size. The tentacles are triangular in cross-

section and have sharp edges.

The prepharyngeal band has two raised blades that are close to each other;

it describes curves with no relation to the branchial folds. There is no dorsal

‘V’. The dorsal tubercle is large, protruberant and opens in a ‘C’. The

100 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 48. Styela angularis.

dorsal lamina is long and has a smooth margin; its height is clearly greater than

that of the branchial folds. We counted on the right side:

R.En7 OV 127) visGas)el2 (2a) Dule:

SOUTH AFRICAN ASCIDIANS 101

The longitudinal vessels are closely spaced on the folds and almost joined at

the top of the branchial sac. The branchial meshes are square or longitudinally

extended. They contain 4-5 long stigmata near the endostyle and 2-3 between

the folds.

It is impossible to see stigmata on the folds. Parastigmatic vessels are only

apparent when a row is dividing and on the sides of the folds.

The oesophagus entrance is before the bottom of the branchial sac. The wide

stomach has internal parallel ridges (Fig. 48). Half the length of the oesophagus

and the stomach are located below the bottom of the branchial sac. There is no

caecum, but a bridge of tissue unites the stomach and the intestine and contains

the pyloric ducts. The intestine curves after the stomach and follows the dorsal

lamina for a considerable distance towards the cloacal siphon (Fig. 48). The

narrow rectum is not attached to the body wall, and ends in a funnel-like anus

with a fringed margin.

There are two long, straight gonads on each side of the body (Fig. 48). The

ovaries are cylindrical and attached to the body wall, with the minutely divided

testis lobes located on either side. The sperm ducts run down the internal side of

each ovary. The oviducts are deeper, lying next to the body wall.

Some testis lobes may be far from the extremity of the ovary in the posterior

of the body. The protruding female genital papillae open near the cloacal siphon

behind the anus.

The voluminous heart is adjacent to the endostyle. There are some

endocarps between the gonads, numerous near the oral siphon and even much

more numerous in the posterior extremity of the body, where they become

elongated (Fig. 48). The cloacal siphon has a ring of small tentacles.

Distribution

This species extends from Lideritzbucht, Namibia, to the Eastern Cape.

Styela canopus (Savigny, 1816)

Fig. 49A

Styela canopus Savigny, 1816: 45, 154.

Styela partita (Stimpson, 1852) aut. mult.

Styela canopus: Kott, 1985: 112, fig. 48, and distribution.

Styela pupa Heller, 1878: 107, pl. 2 (fig. 13). Millar, 1955: 204, fig. 30.

Tethyum pupa: Hartmeyer, 1911: 569, pl. 5 (figs 1-7).

Tethyum canopus malgalhaense: Hartmeyer, 1911: 522, pl. 57 (figs 18-20).

Styela marquesana: Millar, 1955: 207, fig. 32.

Styela stephensoni Michaelsen, 1934: 157, figs 4-7. Millar, 1964: 175, fig. 12.

?Styela aequatorialis: Millar, 1955: 201, fig. 33.

Material

Several specimens. False Bay; Kommetjie; Port Elizabeth (Monniot coll.).

Description

Ascidiologists have, for about 20 years, remarked on the great environment-

dependent variability of this species. Large specimens, 20-30 mm in size, live

102 ANNALS OF THE SOUTH AFRICAN MUSEUM

in sheltered environments such as mangrove swamps in the same geographic

area aS smaller specimens that live on rocky shores and have a tunic with ridges

and tubercles. Very small individuals less than 10 mm in size and covered with

sand inhabit sandy bottoms. All intermediates are found in the same area. The

three principal variants were described by Millar (1955) under three different

names. |

All samples have in common a cylindrical elongated stomach with well-

formed folds (Fig. 49A), a small caecum, a large intestine that is always

curved, and two gonads on each side (Fig. 49A). One of the gonads may be

missing on the left side in small specimens, and large specimens may have three

gonads on the right side. Each gonad normally consists of a sinuous ovary with

testis lobes adjacent but not adhering to it. In small specimens, there are often

only a few testis lobes, whereas in larger animals they become numerous. The

endocarps are rare in small specimens that are covered with sand.

Distribution

Styela canopus has a wide distribution, and occurs in natural habitats in

shallow coastal regions, as well as extending into harbours and on to wrecks.

Styela materna Monniot & Monniot, 1983

Fig. 49B, C

Styela materna Monniot, C. & Monniot, F., 1983: 81, fig.17 c, d.

Material

Three specimens. Miller’s Point, False Bay, 2 m (Monniot coll.).

Description

Three specimens (less than 10 mm across) were collected in a cavity in a

calcareous seaweed. The tunic is wrinkled on the dorsal side and has some

brown-ochre scales. The tunic is lighter and contains some sand on the ventral

side. The siphons are close to each other and do not protrude. This species is

very similar in external appearance to Styela canopus.

The muscles are strong but not gathered in bundles. There are about

20 stocky tightly-packed oral tentacles that do not alternate precisely. The

prepharyngeal band is thin and consists of a single crest. It is only slightly

indented dorsally. The dorsal tubercle protrudes and is urn-shaped. The dorsal

lamina is thick, low and rather long. The branchial sac has four folds per side.

We counted on the right side:

R.E. 0 (5) 1 (6) 1 (6) 2 (8) 2 DLL.

The longitudinal vessels on the right of the dorsal lamina run parallel with

it. We counted 5-6 stigmata per mesh between the folds and 2-3 on the folds.

The stigmata are rows regularly cut by a strong parastigmatic vessel. The

digestive tract (Fig. 49B) is long. The cylindrical oesophagus opens into a wide

and elongated stomach that has a thin wall with about 15 well-marked grooves.

No caecum was found. The intestine ends in a narrow anus with small lobes.

SOUTH AFRICAN ASCIDIANS 103

Fig. 49. A. Styela canopus. B. Styela materna. C. Tadpole of Styela materna.

There are two short, protruding ovaries on each side (Fig. 49B). The

oocytes are compacted and have a polygonal shape. Some round testis lobes are

loosely associated to each ovary (Fig. 49B). The sperm ducts are very thin and

short and difficult to see even after staining. The genital ducts are very short.

There are numerous endocarps on the body wall (Fig. 49B). The cloacal

siphon has a short velum and a dense circle of cloacal tentacles on a wide ring.

This ring extends anteriorly as a dense tentacular field to reach the

prepharyngeal band (Fig. 49B).

Styela materna has the rare attribute in the genus of brooding its eggs.

Larvae (Fig. 49C) are numerous in the cloacal cavity. Their trunks measure

370 um in length and 19 pm in width; the notochord is 760 um long and only

rarely is a membrane found around it. The larvae have three anterior adhesive

papillae and one sensory organ.

104 ANNALS OF THE SOUTH AFRICAN MUSEUM

Remarks and distribution

This species was previously recorded from South Georgia at 66-180 m

depth. The type specimens are larger than the South African material, 12 mm

instead of 6-7 mm, and thus have male gonads more developed. The testis lobes

in those specimens are tightly compressed and clearly have genital ducts. The

branchial sac in the South Georgian specimens have up to 20 vessels in a fold.

These differences are insufficient to erect separate species.

On the other hand, the similarities with Styela canopus are disturbing and

include the gut shape, gonads and branchial sac. Larval brooding in S. materna

is the only characteristic that allows the separation of the species from the

multiple forms of S. canopus. Brooding remains an exceptional feature in the

genus Styela.

Family Pyuridae

Microcosmus oligophyllus Heller, 1878

Figs 50A, 51A

Microcosmus oligophyllus Heller, 1878: 101, pl. 3 (fig. 21). Hartmeyer, 1912: 247, pl. 41

(figs 1-3). Millar, 1955: 211, fig. 36; 1962: 196, fig538:

Microcosmus oligophyllus wahlbergi Michaelsen, 1921: 2, pl. 1 (figs 8-9). Michaelsen,

1934: 161.

Material

Two specimens. Miller’s Point, False Bay, and Gerickespunt (Sedgefield),

low tide (Monniot coll.).

Description

The specimens are 10-30 mm across and have a thick, hard tunic with a

dark red, wrinkled surface partially covered with epibionts. The siphons

protrude slightly and are close to each other. The body is often irregular in

shape as the tunic penetrates rock crevices. The tunic, 1-2 mm thick, has a

white interior surface. The siphon spines (Fig. 51A) are spaced far apart.

They are sharply pointed and have enlarged bases. The musculature is strong,

made of ribbons in an almost continuous layer except above the endostyle and

under the gut. The siphon sphincters are particularly strong, and are up to 2 mm

thick. Both siphons have an internal velum consisting of two layers, the outer

one stiff and the inner one thin and bearing thin filaments. The internal velum

forms four pockets in the oral siphon. There are 24 stout oral tentacles in three

orders of size, with two sets of ramifications. The prepharyngeal area has raised

papillae (Fig. 50A). The prepharyngeal band has two crests and curves in

a dorsal ‘U’. The dorsal tubercle is large, slightly protruding, with horns

internally rolled. The dorsal lamina is long and low, encircling the oesophagus

entrance.

The branchial sac has five high folds on each side. We counted:

R.E. 0:9) 3 15) 3 18) 3 (17) 3 @2) D-L: 2 22) 3°07) 3: 9)3" eae

|B)

SOUTH AFRICAN ASCIDIANS 105

Fig. 50. A. Microcosmus oligophyllus. B. Microcosmus psammophilus.

C-D. Microcosmus squamiger.

Most ventral folds do not reach the posterior of the branchial sac. The

dorsal lamina has a wide unperforated band on the right side that is crossed by

wide transverse vessels. On average there are seven longitudinal vessels in a

mesh between the folds and 3-4 on the folds. They are sometimes intersected by

parastigmatic vessels. The stigmata are short.

The gut and the gonads are wrapped in a loose tissue that obscures their

outline. The stomach is wide and covered with two lobes of an hepatic gland

(Fig. 50A). The one closest to the oesophagus is the largest, and it is also

enclosed in the loose tissue. The hepatic lobes are wrinkled and lack protruding

papillae. The intestine forms a loop in which the two limbs are closely apposed

(Fig. SOA). The smooth anus is located at the oesophagus entrance.

The gonads were not fully developed and consisted of poorly defined masses

inside the body wall. The gonad on the right side is in an anterior position; the

one on the left side does not cross the gut (Fig. 50A) as in other Microcosmus

species, as there is no room for it. The sperm ducts are directed towards the

106 ANNALS OF THE SOUTH AFRICAN MUSEUM

cloacal siphon as is usual. The oviducts are curved along the ventral side of the

ovary and reach the anterior part of the body, a unique arrangement in the

family Pyuridae. In all specimens, a large brown inclusion was observed in the

heart.

Microcosmus oligophyllus is characterized by its five branchial folds and

gonad morphology. The subspecies described by Michaelsen (1921) was only

based on a different number of longitudinal branchial vessels, and he later

hesitated about its validity (Michaelsen 1934).

Distribution

Microcosmus oligophyllus has only been recorded from South Africa.

Microcosmus psammiferus C. Monniot sp. nov.

Figs 50B, 51B, C

Material

Holotype. SAM-A25861, from wreck on Mossel Bay beach (34°12’S

22°08’E), collected by C. and F. Monniot, Feb 1996.

Other material. Two specimens, locality data as above (Monniot coll.).

Description

The three aggregated specimens are entirely covered with sand. They may

have been slightly attached to the substratum or were free-living in sand. On the

contracted animals, the siphons reveal themselves only by reddish tunical

papillae. The siphons have a purple exterior tunic and an internal lining with

eight alternating red and yellow bands. The siphon spines (Fig. 51B, C) are of

two types. Those at the edge of the siphon are sharp, 25 pm long and tightly

packed (Fig. 51B). Those more internal are pedunculate, urn-shaped and 35 ym

long (Fig. 51C). Both kinds of spines are usually separated (Fig. 51B) but may

be intermixed where they meet. Over the body, the tunic is whitish, thin, and

the outer layer is encrusted with sand and bears short rhizoids 0.5 mm long.

Most of the digestive tract and the gonads are located on the ventral side

(Fig. 50B). There are 16 large oral tentacles in three orders, with numerous

ramifications.

The prepharyngeal band has a single crest and is dorsally indented. The

dorsal tubercle is large and protruding, with an anterior aperture and internally

rolled horns. The dorsal lamina is anteriorly low with a smooth edge, and

posteriorly higher with an irregularly dented rim. It joins a smooth annular crest

that encircles the oesophagus entrance.

Fig. 51 (see facing page). A. Siphonal spinules of Microcosmus oligophyllus. Scale bar =

20 um. B-C. Siphonal spinules of Microcosmus psammophorus. A. Limit between the

sharp distal spines of the siphons and the most internal urns. Scale = 50 wpm. C. Detail of

the urns. Scale = 20 pm. D-E. Microcosmus squamiger. Scales, D = 50 um, E = 10 pm.

E. Pyura stolonifera. Scale bar = 20 um.

SOUTH AFRICAN ASCIDIANS

Be)

108 ANNALS OF THE SOUTH AFRICAN MUSEUM

The branchial sac is small relative to the body. The endostyle is obscured

from the ventral side by the intestine and the right gonad that are close to each

other, and only separated by a voluminous heart. The endostyle adheres to the

stomach and the intestine.

The branchial sac has six folds. We counted:

R.E. 1 (12) 3 (18) 1 (18) 2 C15) 2 (12) 2 (18) 0 D.L. 0 (19) 2 (10) 1 (19) 1 19)

Or) 27D) eee

The branchial formula is rather iepeeulor as the number of longitudinal

vessels between the folds varies, some of them appearing irregularly. The

stigmata are obviously coiled at the top of the branchial folds. A single coiled

stigma occupies the area between the axial longitudinal vessel of the fold and the

first or second vessel on the side of the fold. The stigmata are only cut at the

level of the transverse vessels, from the third longitudinal vessel on the sides of

each fold.

The gut loop is narrow with parallel limbs. The oesophagus is short. The

large hepatic gland is not erect and consists of whitish tissue with low ridges.

The rectum is short and the anus has a smooth edge and opens at the wel of the

oesophagus entrance.

There is one gonad on each side (Fig. SOB) with an unusual morphology for

the genus Microcosmus. The cylindrical ovary is surrounded by a mass of testis

lobes. Very numerous sperm ducts join a common sperm duct that lies against

the ovary and almost conceals it at its terminal end. The left gonad crosses the

intestine, and the testis internally covers a large part of the intestine, and the

hepatic gland, in a thin layer.

There are no endocarps and no cloacal tentacles. The velum is higher

dorsally.

Remarks

This species belongs to a group that is actually intermediate between

the genera Microcosmus and Hartmeyeria. The genus Hartmeyeria Ritter,

1913, has few species: H. triangularis, the type species of the genus from

Alaska; two Japanese species H. orientalis Oka, 1929, and H. chinensis

Tokioka, 1967; the Atlantic H. hupferi (Hartmeyer, 1909); and H. bouilloni

Monniot, C. & Monniot, F., 1976a, from Mozambique. The specimen

described by Millar (1962) under the name Microcosmus pedunculatus Pérés,

1951, probably corresponds to H. bouilloni. These five species have in

common: spiral stigmata at the top of the folds, the second fold being reduced to

one vessel; muscles with a peculiar distribution; and a naked peduncle arising

from the ventral side of the body wall through a ‘button-hole’. This group is

very homogeneous.

Hartmeyeria monarchica Hartmeyer, 1922, from Aden, is insufficiently

known; it has a similar branchial sac.

Cynthia formosa Herdman, 1882 (and its synonym Microcosmus spinifera

(Herdman, 1899)) does not belong to the genus Hartmeyeria as Kott (1985)

suggested, but is closer to Microcosmus psammiferus sp. nov. Millar (1966),

who had encountered the genus Hartmeyeria in western and southern Africa,

considered this species to be a Microcosmus.

SOUTH AFRICAN ASCIDIANS 109

The two species M. formosa and M. psammiferus differ in their appearance,

but have coiled stigmata at the top of the branchial folds, a second branchial

fold that is not reduced to a single vessel, no characteristic peduncle, and the

tunic is not embedded with sand, as it is in the true Hartmeyeria species. We

consider that both species have somewhat peculiar characteristics for the genus

Microcosmus, but our knowledge is not yet sufficient to justify their transfer to a

new genus.

Microcosmus squamiger Hartmeyer & Michaelsen, 1928

Figs 50C, D, 51D, E

Microcosmus claudicans ssp. squamifer Hartmeyer & Michaelsen, 1928: 405.

see Microcosmus squamiger Kott, 1985: 356, figs 175e-f, 178. |

Microcosmus exasperatus non Heller, 1878. Monniot, C. 1981: 59, fig. 1.

?Microcosmus exasperatus: Millar, 1955, fig. 35; 1962: 197.

Microcosmus squamiger: Lambert & Lambert, 1998.

Material

Two specimens. Knysna, on buoys (Monniot coll.).

Description

The specimens measure 30 x 20 mm and are attached on the left-posterior

side. The siphons are closely spaced and protrude slightly. The colour is reddish

brown. The tunic is leathery, often covered with epibionts, and nacreous on the

interior. The siphonal spines (Fig. 51D, E), are 25 wm long and have the

characteristic ‘roof tile’ shape of the species. They have spiny rims (Fig. 51E).

The body wall is brownish and opaque. The musculature consists of ribbons in a

layer that is continuous except under the gut.

There are 24 stout, very ramified oral tentacles distributed in four orders.

The prepharyngeal area is narrow and covered with small papillae. The

prepharyngeal band has two thick crests. It forms a dorsal ‘U’ entirely occupied

by the large protruding dorsal tubercle, the opening of which forms two

opposing spirals (Fig. 50C). The dorsal lamina is long and rises in height near

the oesophagus entrance. It is not linked to any branchial fold. Its rim has small

lobes. The sides of the endostyle are covered with small papillae.

The branchial sac has a different number of folds on each side. Thus, there

may be eight complete and two incomplete folds on the right side, and six

complete and two incomplete folds on the left side. There are generally

15-20 vessels on the complete folds and a single vessel between the folds. The

vessel between the folds belongs to the dorsal part of the next fold. The number

of stigmata varies in different parts of the branchial sac. Generally there are

parastigmatic vessels. The transverse vessels do not bear papillae.

The stomach is covered by a large hepatic gland divided into several

uniform lobes (Fig. 50C). The lobes consist of parallel lamellae, the rims of

which are covered with small papillae. The rear intestine curves to join the

middle part of the intestine forming a secondary loop (Fig. 50D) far less

110 ANNALS OF THE SOUTH AFRICAN MUSEUM

accentuated than in Microcosmus exasperatus. The rectum is attached to the

body wall and the branchial tissue. The anus has a smooth edge.

There is a gonad on each side more or less distinctly divided into three lobes

(Fig. 50C). The right gonad is located far to the anterior, leaving a large empty

area behind it (Fig. 50C). The ovary is central and the testes are placed around

it. The gonoducts are very short and sometimes hidden under the testis mass.

In this species the endocarps are very reduced, surrounding the gonads and

the posterior intestine in a kind of envelope. There are no independent

endocarps. Both siphons have large velums. A ring of tentacles lies at the base

of the cloacal siphon.

Remarks and distribution

This species has been confused with M. exasperatus. It differs from it in

spinule shape (Fig. 50C, D) and the secondary bend of the gut. It is possible

that the specimen named M. exasperatus by Millar belongs to this species; the

description could correspond to either species.

The synonymy given by Kott (1985) is probably incomplete, as some

descriptions of M. exasperatus not cited by Kott mention a gut without a

pronounced secondary loop.

Microcosmus squamiger is a species of Australian origin, where it is

encountered in natural habitats. It colonizes harbours and was recorded in the

Mediterranean Sea from Italy and Tunisia in 1981. Lambert & Lambert (1998)

reported its arrival in California. Since then it has become cosmopolitan. The

South African populations were probably also imported.

Pyura capensis Hartmeyer, 1911

Fig. 52

Pyura capensis Hartmeyer, 1911: 561, pl. 47 (fig. 10), pl. 57 (fig. 8). Millar, 1962: 195,

fig. 37.

Material

One specimen. False Bay (Griffiths coll.).

Description

The specimen was attached by the posterior part of the left side. The body

(SO x 30 mm) is cylindrical. The siphons are terminal and protruding, 10 mm

apart, with four lobes. The tunic is hard and covered with tubercles. The whole

tunic is covered with brown, sclerified plates on a paler ground. We have not

seen siphonal spines either in light microscopy or scanning electron microscopy.

In formalin the colour turns ochre with a thin pink ring around the siphons.

The musculature is strong, continuous on the whole opaque body except

below the gut. There are about 20 large oral tentacles and 10 smaller ones,

irregularly distributed. All of them bear three orders of branchings, regularly

arranged. The prepharyngeal band lies between two equal crests, draws a dorsal

‘V’, and is prolonged under the dorsal tubercle by a small groove. The dorsal

SOUTH AFRICAN ASCIDIANS 111

Fig. 52. Pyura capensis. A. Specimen opened along the ventral line, endocarps not figured.

B. Dorsal tubercle. C. Pedunculate gonad lobe covered by endocarps.

tubercle is protruding with a characteristic shape (Fig. 52B) and a ramified

aperture, already mentioned by previous authors.

The dorsal tubercle is hidden under the oral tentacles. The dorsal lamina

forms short pointed languets on an unperforated band where the transverse

vessels disappear. Consequently the dorsal languets do not correspond to the

vessels and may be displaced on the right and chiefly on the left side. The dorsal

lamina finishes at the anterior part of the protruding roll encircling the

oesophagus entrance.

Seven branchial folds recover each other on each side. We counted on the

right side:

Rens 1) 3 (12)'5°(16) 4 (17)5'149) 3:6) 3:5) 3 D.L.

The seven folds extend the whole length of the branchial sac. They converge

and are abruptly cut at the oesophagus entrance, the longitudinal vessels ending

in a sharp papilla. In addition, in the very posterior part, there is one fold on the

right side and two on the left side. They are formed by 2-5 vessels and do not

reach the oesophagus. The first vessel on the right of the dorsal lamina parts

from it posteriorly. The space left is irregularly perforated.

The branchial vessels are high. The branchial meshes are transversely

lengthened. We counted 8-12 oval stigmata in a mesh between the folds and 5-8

on the folds. At the top of the folds, indications of the generative spirals persist.

There are parastigmatic vessels in some places.

112 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 53. Pyura stolonifera. A. Young specimen. B. Dorsal tubercle of the same.

The gut forms a closed loop in the posterior part of the body (Fig. 52A). A

curved oesophagus enters a slightly enlarged stomach. The hepatic gland forms

three swollen lobes (Fig. 52A). The long rectum ends in an anus with two

scalloped lobes.

The gonads are also located in the posterior part of the body (Fig. 52A).

The gonadal ducts constitute an axis with few ramifications, and around these

branches are clusters of hermaphroditic lobules, often without any contact with

the body wall. The genital ducts end in two wide papillae with dented rims,

opening a short distance behind the anus (Fig. 52A). Each gonad lobule is

covered on its cloacal side by about ten endocarps (Fig. 52C). The remainder of

the body wall and the gut is covered with long, tight endocarps, more than a

hundred per square centimetre. It was impossible to draw them. The cloacal

siphon is internally encircled, mostly in the posterior part, by a line of elongated

papillae, resembling endocarps but longer and with small ramifications that

correspond to cloacal tentacles (Fig. 52A).

ata —

SOUTH AFRICAN ASCIDIANS 113

Distribution

Pyura capensis is geographically limited to the Western Cape Province.

Species of the Pyura stolonifera-group

Amongst material attributed to Pyura stolonifera several distinct species

were described, two from South Africa and one from Australia. The Australian

species has also been recorded on the Pacific coast of South America and along

the west coast of Africa from Dakar to the Gibraltar Strait. Specimens from

these locations were compared with South African samples and studied by

Monniot & Bitar (1983). The most important difference concerns the

arrangment of the right gonad lobes: in one line in P. stolonifera and in two

lines in the Australian specimens. We now identify the Australian population as

Pyura praeputialis (Heller, 1878) sensu lato. In that species, Kott (1985)

pointed out differences, also noted by Dalby (1994) in his Ph.D. dissertation. In

subsequent publications Dalby (1995, 1996) stated that both morphologies found

in the Australian population are genetically controlled, and consequently

represent two species, but no taxonomic decision has been published.

In South Africa, a similar case occurs as two forms can be recognized in the

field. The internal differences are less obvious but nevertheless exist. They

already appear in young specimens and they are described here from these

specimens. They correspond to the two species Pyura stolonifera (Heller, 1878)

and Pyura herdmani (Drasche, 1884). Both species may reach more than 10 cm

- in length when adult. The large specimens have a complex morphology difficult

to interpret, so the drawings were made from small juvenile specimens, where

the characteristics already appear.

Pyura lignosa Michaelsen, 1908 sensu stricto (Monniot, C. 1994), from the

west coast of Panama is allied to this species group.

Pyura stolonifera (Heller, 1878)

Figs 51F, 53

Cynthia stolonifera Heller, 1878: 92, pl. 2 (fig. 10).

Microcosmus coalitus Sluiter, 1898a: 57, pl. 2 (fig. 8), pl. 7 (figs 9-10).

Halocynthia vanhoffeni Michaelsen, 1904: 197, pl. 10 (fig. 13), pl. 12 (fig. 44).

Cynthiopsis coalitus: Michaelsen, 1904: 210.

Pyura (Halocynthia) stolonifera: Hartmeyer, 1912: 246 (part.).

Pyura Stolonifera: Millar, 1962: 193, fig. 36C (part.).

Material

Several specimens. False Bay, 0-2 m (Griffiths and Monniot coll.).

Description

From very shallow water, this species forms soft spheres, generally covered

with epibionts. Both its siphons are large, close together, and most often with

tubercles. The siphonal spines are 25-30 pm long (Fig. 51F), and are stout and

originate from a slightly protruding base. They are cone-like with a blunt tip.

114 ANNALS OF THE SOUTH AFRICAN MUSEUM

Out of the tunic the lobes of the siphons are toothed. The large tentacles are

very ramified to make an efficient filter at the branchial sac entrance. The dorsal

tubercle protrudes in two spiral cones. Its opening follows a curved line, even in

small specimens; the opening has characteristic undulations (Fig. 53B). The

dorsal lamina is very short, made of languets and connected to a wide circular

area encircling the oesophagus entrance. The endostyle is very long, more than

ten times that of the dorsal lamina. 7

The branchial sac has six folds in arcs. All the folds end at the oesophagus

entrance by a series of papillae that correspond to the longitudinal vessels.

As the siphons are close together, the oesophagus is long. The stomach is

not dilated and is covered by a voluminous hepatic gland with lobes in the shape

of cauliflower (Fig. 53A). The anterior lobe (figured here cut in two parts)

overflows on to the right of the body side. The intestine describes a marked

loop, but its way is hidden by endocarps. The rectum is short. The anus has a

smooth or slightly lobed rim.

There is one gonad on each side made of few lobes in only one line

(Fig. 53A). These lobes are covered with large irregular endocarps. The

gonadal ducts open near the cloacal siphon in a papilla uniting the oviduct and

sperm duct. The figured specimen (Fig. 53A) is not adult and the endocarps

covering the lobes may give the appearance of two rows of lobes. In large adult

specimens the gonad lobes appear clearly in one row visible as such from the

external side of the body once it has been removed from the tunic.

Distribution

This species occurs from Namibia, along the west coast of South Africa,

and extends eastwards as far as Durban.

Pyura herdmani (Drasche, 1884)

Figs 54, 55A, B

Microcosmus herdmani Drasche, 1884: 370, pl. 2 (figs 3-7).

Cynthiopsis herdmani: Michaelsen, 1904a: 208, pl. 12 (figs 41-43).

Cynthiopsis valdiviae Michaelsen, 1904a: 201, pl. 12 (figs 35-40).

Pyura (Halocynthia) stolonifera: Hartmeyer, 1912: 246 (part.).

?Pyura stolonifera: Millar, 1955: 210, fig. 34.

Pyura stolonifera: Millar, 1962: 193, fig. 36D (part.).

Material

Several specimens. Miller’s Point, False Bay, 2 m; Namibia, Langstrand,

Swakopmund (Griffiths coll.)

Description

Pyura herdmani differs from P. stolonifera in its external appearance.

Young specimens are orange in colour and have large pointed papillae of hard

and naked tunic that make a collar around the siphons. When the animals grow,

the tunic increases in thickness, becomes stiffer and includes sediment. The

papillae around the siphons are less and less visible. The tunic is totally covered

SOUTH AFRICAN ASCIDIANS 115

Fig. 54. Pyura herdmani. A-B. Two young specimens. C. Dorsal tubercle of a

small specimen.

with epibionts and the toothed rims of the siphons disappear. The rare siphonal

spines (Fig. 55A, B) only occur in places, separated by large irregular areas

(Fig. 55A). They are stout, in shorter cones than in Pyura stolonifera,

appearing in buttons. In other places on the internal side of the siphon the tunic

is densely covered with digitiform papillae in the fashion of a velvet cloth

(Fig. 55B). The role and nature of this structure remains unknown.

116 ANNALS OF THE SOUTH AFRICAN MUSEUM

The oral tentacles are identical to those of P. stolonifera. The dorsal

tubercle is very different, sponge-like in adult and even in young specimens. In

very young specimens of only 20 mm, smaller than those shown in Figure 54A,

B, a structure suggesting two spirals remains visible (Fig. 54C), but the opening

is already cut in pieces and becomes irregular. Supplementary coils and

supplementary independent perforations exist. In older but not yet adult

specimens as figured (Fig. 54A), the dorsal tubercle has a spongy appearance.

The dorsal lamina and the branchial sac are similar in P. stolonifera and

P. herdmani. In adult specimens the endocarps cover the whole surface of the

digestive tract and of the gonads (Fig. 54A, B).

The distribution of this species extends from Namibia to KwaZulu-Natal.

Halocynthia spinosa Sluiter, 1905

Figs 55C-F, 56

Halocynthia spinosa Sluiter, 1905: 16, pl. 2 (fig. 8).

Halocynthia spinosa defectiva Millar, 1962: 201.

Halocynthia defectiva: Millar, 1964: 178, fig. 14.

Halocynthia spinosa Monniot, C., 1973: 60, fig. 4c.

Material

Several specimens. False Bay, 6 m (Griffiths coll.); Ibo Island, Mozambique

(Monniot coll.)

Description

The largest specimen is 50 mm long. It was attached by the posterior part of

the ventral side. Both siphons are long (10 and 15 mm) and close. In life the

colour is pink, paler and yellowish on the siphons. The tunic is tough but

flexible, entirely covered with small tubercles with a central spine or a branched

spine circled by 4-6 smaller ones (Fig. 55D). Near the siphons the tubercles are

more protruding, with lateral spines almost as long as the central one

(Fig. 55C). Inside the siphons, in the deeper part, the siphonal spines are made

of a central sharp point flanked by very small spines (Fig. 55F). More distally,

the short spines surrounding the central one lengthen and reach a large size

(Fig. 55E). The final structure results in a body that resembles a spiny ball with

a crown of long points at the top. The spines on the siphons are not longer than

those on the sides of the body.

The body wall is made opaque by a well-developed musculature. Twenty-

five oral tentacles in 3-4 orders of size are laterally flattened and anteriorly

curved, like sickle blades. The posterior sides of the tentacles bears two rows of

Fig. 55 (see facing page). A-B. Pyura herdmani. A. Siphonal spines. Scale bar = 20 um.

B. Internal siphonal papillae. Scale bar = 10 ym. C-F. Halocynthia defectiva. C. Spines of

the siphonal rim. Scale bar = 200 um. D. Spines of the external side of the siphons. Scale

bar = 200 um. E. Spines of the internal distal part of the siphons. Scale bar = 100 um.

F. Spines of the deep internal part of the siphons. Scale bar = 100 pm.

SOUTH AFRICAN ASCIDIANS

Fig. 55

118 ANNALS OF THE SOUTH AFRICAN MUSEUM

digitiform branches themselves divided two times again. The branches are

perpendicular to the primary tentacle. The prepharyngeal band has two equal

crests. It makes undulations around the branchial folds and traces a dorsal ‘V’

(Fig. 56A). The dorsal tubercle is very protruding with two curled horns

(Fig. 56B). The dorsal lamina is made of long languets corresponding to the

right transverse vessels. The transverse vessels on the left also end in smaller

papillae, and this gives the aspect of a doubled dorsal lamina. The dorsal lamina

is interrupted before the oesophagus entrance.

The branchial sac is made of ten complete folds on each side, to which

are added one ventral fold on the left and two on the right in the very anterior

part. The folds are high, recovering each other. We counted 20-30 vessels on a

fold and 2-4 between the folds. The meshes are tranversally elongated each

with 10-14 stigmata between the folds and 4-6 on the folds. The stigmata

are rather short, often cut by parastigmatic vessels. At the oesophagus

entrance, the folds are suddenly interrupted and the longitudinal vessels end in

papillae.

The gut forms a wide loop (Fig. 56A). The long oesophagus enters a wide

stomach. The anterior part of the hepatic gland shows internal ridges in its

longitudinal axis; the posterior part is raised in many papillae (Fig. 56A, C).

The rectum is not attached to the body wall; it ends in a widely opened anus.

The two gonads are located on the intestine. The most anterior one lies

entirely over the intestine, the posterior one crosses the intestine and extends

into the space between the two limbs of the gut (Fig. 56D). The ovary is

central, not protruding. The testis lobes extend on each side of the ovary in a

thin layer covering the whole free intestinal surface (Fig. 56A). The gonads

open by two papillae on the intestine. The disposition of the gonads is totally

masked in aged specimens and can only be deciphered in young individuals

(Fig. 56D).

The right side of the body is covered with endocarps (Fig. 56A). Some of

them also lie inside the gut loop, but none above the intestine.

Both siphons have a short velum, the cloacal one with round lobes at the

base.

Remarks and distribution

Halocynthia defectiva is closely allied to H. spinosa Sluiter, 1905. Both

species have in common the presence of only two gonads, located on the left

side, above the intestinal loop. Halocynthia spinosa, living in the Red Sea, has

large siphons with, on their edge, 2-mm long ramified spines, slightly ramified

tentacles, a low dorsal tubercle, 7-9 complete branchial folds and only one

supplementary fold on the right side, and both gonads located over the

descending limb of the intestine.

The sample from Bahrain described by Millar (1975) under the name

Halocynthia arabica defectiva corresponds, in our opinion, to a true H. spinosa

with large ramified spines, poorly ramified tentacles and gonads crossing the

intestine.

Halocynthia spinosa has been recorded from the Red Sea and Arabian Gulf

and its distribution extends to False Bay, South Africa.

SOUTH AFRICAN ASCIDIANS We)

Fig. 56. Halocynthia defectiva. A. Large specimen. B. Dorsal tubercle. C. Detail

of the hepatic gland of a young specimen. D. Gonads of a young specimen.

Family Molgulidae

Molgula conchata Sluiter, 1898a

Fig. 57

Molgula conchata, Sluiter, 1898a: 58, pl. 7 (figs 11,14). Millar, 1955: 214, fig. 38; 1962:

203, fig. 43.

Ctenicella conchata: Hartmeyer, 1914: 14, fig. 6.

Ctenicella natalensis Michaelsen, 1918: 2, figs 9-11.

Molgula natalensis Vasseur, 1967: 121, pl. 7 (figs 63-68).

non Molgula conchata: Monniot, C., 1969: 651, fig. 111.

120 ANNALS OF THE SOUTH AFRICAN MUSEUM

Material

Several specimens. Port Elizabeth, intertidal; Knysna (Monniot coll.).

Description

This Molgula species has a large size, up to 40 mm. It was found on rocks

in the littoral zone. The tunic is embedded with sediment throughout its

thickness. The body is often covered with epibionts, mostly with hair-like

bryozoans. The siphons are close together, in hollows and encircled by a ring of

hard and thick tunic. A thickening of the body wall corresponds to this ring of

tunic. The siphonal lobes are deeply cut. The musculature is only developed on

the dorsal side of the body. It is made of short ribbons around each siphon and

in the area between the siphons. The muscle arrangment exactly follows the

pattern of the hollows of the tunic. The remainder of the thin body wall is

devoid of muscular bundles. The oral tentacles are not numerous, only 16, in

two orders of size, and some very small ones. The tentacles are thick with

numerous regular branches in four orders. The tentacular ring closes the siphon

aperture. The prepharyngeal band draws marked curves at the level of the

branchial folds and has a deep dorsal ‘V’. It is made of two irregular rims, the

posterior higher.

The dorsal tubercle is protruding, its opening in the shape of a transverse

‘S’ (Fig. 57C). The dorsal lamina is short as the siphons are closely placed.

The branchial sac has seven folds on each side. On the right side we

counted:

R.E. 0 (8) 0 (9) 0 10) 0 11) 0011)011) 011) 0 DLL.

The folds are very asymmetrical and the most dorsal vessels, in variable

number, are very thin. The longitudinal vessels of the folds fuse into a

continuous band at the oesophagus entrance. The branchial sac has a uniform

structure in all parts with longitudinal stigmata between the folds and

infundibula under the folds.

The gut follows a double closed loop (Fig. 57B, C). The oesophagus is

short, largely covered by the hepatic gland. There is no stomach dilatation. The

anus, with a smooth rim, is attached to the side of the oesophagus entrance.

The gonads are made of a massive and protruding ovary, partly covered by

the testis. The latter forms a crown around the blind extremity of the ovary. The

oviduct and sperm duct are independent. The arc-shaped kidney is full of

concretions. The cloacal siphon has a wide muscular velum, as does the oral

siphon.

Remarks and distribution

Millar (1962: 204, figs 42, 43c) described Moiguia cryptica trom Faise Bay,

a species very closely allied to M. conchata. Both species have the same kind of

gonads, gut and siphons. These species differ by the tissues consistency, the

length of the siphons, and the number of branchial vessels. The intestine of

M. cryptica draws a less-closed loop and the gonad is applied on the bottom of

the loop. In addition, Molgula cryptica is a brooding species. Millar (1962) has

compared his species to the Antarctic M. pulchra. Monniot, C. (1969) described

a population of M. conchata from Dakar. This synonymy is erroneous. The

SOUTH AFRICAN ASCIDIANS 121

specimens from Dakar have the same gut shape but the ducts of the gonad are

different.

Molgula conchata is recorded from Mauritius and South Africa.

Fig. 57. Molgula conchata. A-B. Right and left sides of a specimen. C. Specimen opened

along the ventral line.

Molgula falsensis Millar, 1955

Figs 58, 59

Molgula falsensis Millar, 1955: 217, fig. 40; 1960: 129, fig. 55; 1962: 203, fig. 43A; 1964:

179.

Material

One large specimen: Miller’s Point, False Bay, 6 m (Griffiths coll.). Several

small specimens: Saldanha Bay Harbour and Port Elizabeth Harbour (Monniot

coll.).

122 ANNALS OF THE SOUTH AFRICAN MUSEUM

Description

Brooding specimens with a soft tunic

The population is made of agglomerated spheres. The tunic is covered with

short rhizoids that accumulate sediment particles and debris. The tunic is thin

and soft. The slightly protruding siphons have sharp lobes on their rims. The

muscles form about 30 short and thick bundles on each siphon; they are absent

in the middle of the dorsal side between the siphons. Some short muscles lie

along the ventral side. About 30 oral tentacles are distributed in three orders.

They are long with three sets of finger-like ramifications.

The prepharyngeal band has two thick rims; it draws a low dorsal ‘U’. The

dorsal tubercle is large and protruding. Its opening is a ‘U’ with sides slightly

inwardly curled. The dorsal lamina is short. The branchial wall has seven folds

on each side; the branchial formula is:

R.E. 0 (2) 0 (4) 0 (5) 0 (6) 0 ) 0 (5) 0 (3) O DLL. 0 (3) 0 G) 0 G) 0 () 0 ©)

0 (4)0@G)0E.L.

The longitudinal vessels are high and thin. On the ventral side of the folds

they can recover each other. The six primary infundibula are cut up into

Fig. 58. Molgula falsensis. Brooding specimen. A-B. Right and left sides.

C. Internal structure.

SOUTH AFRICAN ASCIDIANS 123

3-4 secondary infundibula along the fold axis. At this level, the branchial

perforations are irregular with numerous exoinfundibula. Between the folds, the

stigmata are longitudinal. They are short, cut in pieces, and sometimes make

exoinfundibula. At the level of the oesophagus entrance the longitudinal vessels

fuse to constitute a continuous membrane.

The gut (Fig. 58B, C) has a slightly curved secondary loop. The hepatic

gland covers the whole anterior part of the gut. It is massive, made of

irregularly distributed lamellae. The rectum is short with a smooth rim around

the anus. The kidney is widely spread but only slightly protruding.

The gonads (Fig. 58A, B, C) have a central ovary circled by a ring of testis

lobes that partially cover the ovary. The arrangement of the testis lobes on the

Ovary varies. among the individuals. There is a single sperm duct in the middle

of the gonad. The oviduct opens through a large papilla close to the cloacal

siphon.

All the collected specimens contained a large number of segmented eggs,

reaching the morula stage.

Specimen with hard tunic

The body forms a slightly flattened ball 30 x 25 x 21 mm. The oral siphon

is terminal, the cloacal siphon is 13 mm away. The conical siphons have six and

four sharp lobes at their top. The tunic is 1 mm in thickness, stiff and whitish.

The anterior part of the body is naked or with few epibionts, the posterior part

bears finger-like rhizoids accumulating debris and sediment.

The body wall is fleshy but translucent. The muscles are made of about

30 bundles radiating from each siphon, except between the siphons where they

are absent. The muscular bundles are short and on both sides are interrupted

before the level of the gonads and gut. The most dorsal muscles of each side

join but do not fuse.

There are 12 oral tentacles arising from a protruding ring. They have large

first-order ramifications covered with numerous ramifications of second and

third orders. The prepharyngeal band is thick, undulated at the level of the

branchial folds (Fig. 59C). It draws a pronounced dorsal ‘V’. The dorsal

tubercle protrudes with the two horns of the right-hand opening slightly curled.

The branchial sac has seven folds. The right-side formula is:

ROE” 0-12) 1:2) 1 4) 1. G6) 1 G6)-1 G6) 1 G3) 1 D.L.

The vessel located between the folds represents the most dorsal vessel of the

next fold. The vessels are thicker on the ventral side than on the dorsal side of

the folds. At the level of the oesophagus entrance, the folds are interrupted,

the vessels fuse to make a kind of protruding wide-mouthed funnel to the

oesophagus. The six primary infundibula are cut out into 4-6 secondary bispiral

infundibula. Between the folds, over the primary infundibula the longi-

tudinal vessels are cut in short pieces. There are no exoinfundibula between the

folds.

The intestine draws a slight secondary loop (Fig. 59B, C). After a very

short oesophagus, the stomach is covered with a large hepatic gland made of

irregular lamellae. The intestine is covered with a diffuse part of the hepatic

gland that hides its shape. The rectum is short, the anus has a plain rim.

124 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 59. Molgula falsensis. Specimen with a hard tunic. A-B. Right and left sides.

C. Internal structure.

The gonads lack a definite outline (Fig. 59A, C). They are made of the

central ovary covered by a mass of testis lobes. On the right side the testis lobes

partly encircle the kidney. On the left side they spread on a large part of the gut

(Fig. 55C). Each testis opens by a single papilla in the middle of the gonad. The

female papilla is round and protruding. No segmented eggs were present in the

cloacal cavity of this specimen.

The kidney is voluminous. The cloacal siphon is encircled by a short velum.

Remarks and distribution

Between 1955 and 1964, Millar described three forms of Molgula falsensis.

In all three cases, the species are small, 15 mm maximum, with a thin tunic

covered with hair. None of his descriptions mentions brooding.

In our collection we have identified two forms. One of them has a large size

(30 mm), with a largely tunic, smooth, thick and rigid. The other is smaller

(15 mm) with a soft tunic covered with hairs and sediment, and it is brooding.

The large specimen was collected at False Bay in a natural site, the small

specimens in harbours at Saldanha Bay and Port Elizabeth. Both forms are

SOUTH AFRICAN ASCIDIANS 125

closely allied and only differ by the larval brooding and the tunic structure. In

the largest specimen the branchial structure is simpler than in smaller animals.

A similar case occurs in Europe and distinguishes Molgula occulta from

Molgula oculata.

Molgula falsensis is a South African species.

Molgula scutata Millar, 1955

Fig. 60

Molgula scutata Millar, 1955: 215, fig. 39; 1962: 202, fig. 34B. Monniot, C. & Monniot,

F., 1976b: 672. Turon, 1988: 282, fig. 8.

Material

Large-size specimens. Sea Point, intertidal (Monniot coll.); Namibia

(Gibbons coll.).

Small-size specimens (less than 10 mm). Isipingo, intertidal (Griffiths coll.);

False Bay, Gerikespunt, Knysna, 1-2 m (Monniot coll.).

Description

This species was encountered in two different forms, one of a large size

(20-40 mm), the other smaller (5-15 mm) and brooding.

Large form

The specimens from 20-40 mm are weakly attached to rocks. Their tunic,

rather stiff, is covered with sediment, mostly in the siphonal area. The sediment

particles adhere to the body surface, but are not included into the tunic as in

Molgula conchata. Even in contracted animals, the siphons, close to each other,

remain protruding. Their rim is not dentate, but slightly irregular.

The body wall has some strong muscles on the siphons (Fig. 60A, B). They

are interrupted on the side of the body. These bundles are more or less

elongated in varied samples, or they may be very short constituting a ring

around the siphons. There are also some areas with transverse muscles

(Fig. 60A, B). About 12 large oral tentacles in 2-3 orders have elongated

branches of at least three orders. Some very small tentacles are irregularly

intercalated. The prepharyngeal band has two unequal rims, the anterior more

developed. The dorsal indentation is not well marked. The dorsal tubercle is

protruding, of variable shape from a simple slit (Fig. 60C) to a double spiral.

The dorsal lamina is short.

The branchial sac has a characteristic structure. The folds carry two vessels,

both of them lying on the ventral side on the fold. The longitudinal vessels are

wide and high as those observed in the Molgulidae, which have only one vessel

per fold. The stigmata are short, most of them longitudinal. The digestive tract

(Fig. 60B, C) describes a deep secondary curve. The stomach is not enlarged.

The hepatic gland is voluminous. The intestine has a uniform diameter with a

short rectum ending in a smooth-rimmed anus.

On the left side the gonad (Fig. 60C) occupies the whole space between the

two curves of the gut. The ovary, obscure in outline is partly covered by

126 ANNALS OF THE SOUTH AFRICAN MUSEUM

Fig. 60. Molgula scutata. Large specimen. A-B. Right and left sides. C. Internal

structure, brooding specimen. D. Internal structure. E. Detail of the gonad and gut.

F. Larva.

SOUTH AFRICAN ASCIDIANS 127

numerous and very small testis lobes. The gonads do not protrude into the

cloacal cavity. Each opens by elongated sperm duct and oviduct, close to each

other. The cloacal siphon has a muscular velum in a sphincter.

The specimens collected in deep waters off Namibia have a less strong

musculature and a thinner branchial sac, a case often observed in deep habitats.

Small form

The small specimens (Fig. 60D) have the same kind of musculature as the

large ones, but the bundles are thinner and never joined. The 12 tentacles are

short with only ramifications of the first and second order. The dorsal tubercle

has a single curve slightly concave to the right side. The branchial sac is even

with curved stigmata and infundibula under the folds. The shape of the gut is the

same as in a large specimen.

The main differences between these two forms concern the gonads. The

sperm duct opens by a very short papilla far from the oviduct (Fig. 60D, E).

The oviduct is attached to the body wall and opens in a flat papilla instead of an

erect extremity. The small specimens are brooding. The small larvae (Fig. 60F)

have a trunk 170 pum long and a notochord 420 pm long inside the tail.

Millar (1962) indicated that one of his specimens was brooding without

providing further details.

Remarks

In South Africa the genus Molgula is represented by six different forms,

which can be grouped in pairs: Molgula conchata and M. cryptica; two forms of

'M. falsensis; and two forms of M. scutata.

Each pair possesses an incubatory form. We do not have a large enough

sample to estimate the variability within the different species, and the

morphological characters are insufficient to solve the problem. Further

biological studies of the brooding conditions, and molecular systematics are

required to resolve the taxonomy of these forms.

OTHERS ASCIDIANS RECORDED IN SOUTH AFRICA BUT NOT

PRESENT IN THIS COLEECTION

Family Polyclinidae

Aplidium agulhaense (Hartmeyer, 1912). Amaroucium agulhaense Hartmeyer,

1912 (p. 356, pl. 38 (fig. 4), pl. 44 (fig. 11)), from the Agulhas Bank

(102 m depth) is pedunculate with only five rows of stigmata.

Aplidium claviforme (Hartmeyer, 1912). Amaroucium claviforme Hartmeyer,

1912: 348, pl. 39 (fig. 5), from Algoa Bay has club-shaped colonies,

impregnated with sand, with very long zooids. It is insufficiently described.

Aplidium colelloides (Herdman, 1886). Amaroucium colelloides Herdman, 1886

(p. 233, pl. 27 (figs 9-12)), collected off the Cape of Good Hope at 250 m

depth has stalked colonies with zooids in double rows in the head, having

nine rows of stigmata and 12-13 stomach folds. Redescribed by Millar

128 ANNALS OF THE SOUTH AFRICAN MUSEUM

(1962: 125, fig. 4) from the same location, it was also recorded in Namibia

by Turon (1988: 276, fig. 2).

Aplidium exiguum (Herdman, 1886). Psammaplidium exiguum Herdman, 1886

(p. 245, pl. 31 (fig. 11)). This species was also collected at 170 m and at

318 m depth (Hartmeyer 1912: 338, pl. 39 (fig. 1), pl. 44 (fig. 7)) off the

Cape of Good Hope. This species is lobed, embedded with sand. The zooids

have 14 stigmata rows and 20 stomach folds, but are immature.

Aplidium galeritum (Hartmeyer, 1912). Amaroucium galeritum Hartmeyer,

1912 (p. 344, pl. 39 (fig. 4), pl. 44 (fig. 10)), from St Francis Bay, recorded

again in False Bay (Millar 1962: 130; 1964: 172, fig. 10—Cape Province),

has light grey pillar-like lobes, 9-12 stigmata rows and 12-14 stomach

folds. The larvae are distinctive with a dense anterior fringe of small

vesicles.

Aplidium lubricum (Sluiter, 1898a). Amaroucium lubricum Sluiter, 1898a

(p. 31, pl. 1 (fig. 8), pl. 5 (fig. 1)). We have re-examined the type colony,

ZMA TU 185 from Durban, which corresponds well to other records from

Durban, Mozambique and Madagascar (Millar 1956: 915, fig. 2; Vasseur

1968; Monniot, C. & Monniot, F. 1976a: 362, fig. 1C-D). This species

with nine stigmata rows, 15-20 stomach folds, long zooids and a larva with

an anterior fringe of numerous vesicles, is restricted to the tropics.

Aplidium pantherium (Sluiter, 1898a). Psammaplidium pantherinum Sluiter,

1898a (p. 26, pl. 2 (fig. 3), pl. 4 (figs 8-9)). Amaroucium unilarviferum

Millar, 1955 (p. 172, fig. 4; 1962: 123, fig. 3). Millar re-examined the type

from Isipingo and a new collection from Cape Province, pointing out that

the original description was erroneous. The zooids have only five stomach

folds and a larva with an anterior fringe of round vesicles. The species was

also recorded by Millar (1964: 172).

Aplidium retiforme (Herdman, 1886). The type specimen, Psammaplidium

retiforme Herdman, 1886 (p. 248, pl. 32 (figs 8-10)), from Kerguelen, has

been revised (Monniot, F. & Gaill 1978: 149, fig. 6C-F) with additional

collections made in the same area. Millar (1962: 127, fig. 5) recorded this

characteristic species from False Bay, with small slender lobes covered with

sand.

Aplidium sarasinorum (Fielder, 1889). Heterotrema sarasinorum Fiedler, 1889

(p. 859, pl. 25 (figs 1-4)) from Ceylon was recorded again from False Bay

and Mozambique (Millar 1962: 128, fig. 6). The zooids, with an average of

ten stigmata rows and eight stomach folds, have a very short post-abdomen

with a cluster of testis vesicles and a larva with a fringe of numerous

anterior vesicles.

Aplidium schultzei Hartmeyer, 1913 (p. 141), from False Bay, was insufficiently

described to be recognized.

Polyclinum constellatum Savigny, 1816 (p. 189, pl. 4 (fig. 2), pl. 18 (fig. 1)), is

a widely distributed fouling species that was recorded by Millar (1955: 176,

fig. 7) from Durban.

SOUTH AFRICAN ASCIDIANS 129

Polyclinum arenosum Sluiter, 1898a (p. 20, pl. 4 (fig. 12)), from Isipingo, was

later recorded by Millar (1955: 174, fig. 5; 1962: 136, fig. 11) from Cape

Province and Natal. It has a sandy colony divided in narrow lobes made of a

single system each.

Polyclinum neptunium Hartmeyer, 1912 (p. 331, pl. 38 (fig. 9), pl. 44

(figs 2-4)), is very similar to Polyclinum isipengense, but the larva has

different anterior ampullae. This species, described from the Cape of Good

Hope in 106-318 m, was also recorded from equivalent depths in South

Africa by Millar (1962: 136, fig. 11), 248-341 m depth. It is also present in

Southern Australia (Kott 1963, 1972).

Synoicum australe Millar, 1962 (p. 133, fig. 8), from Mossel Bay

(SAM-A25609), not recorded elsewhere.

Synoicum capense Millar, 1962 (p. 131, fig. 7), from False Bay (SAM-

A25608), has not been recorded again.

Family Polycitoridae

Eudistoma mobiusi (Hartmeyer, 1905). Colella mobiusi Hartmeyer, 1905

(p. 396). Polycitor mobiusi: Hartmeyer, 1912 (p. 305), Cape Province and

Madagascar. Eudistoma mobiusi: Millar, 1962 (p. 162), Cape Province. The

species has a large larva 2-mm long but no other distinctive characters. It is

also recorded from Mauritius and Mayotte (Comoros islands), but the

identifications need to be revised.

Eudistoma renieri described as Polycitor renieri Hartmeyer, 1912 (p. 309),

described from St Francis Bay, was recorded by Millar (1962: 160, fig. 23)

from Durban. It has a twisted loop of the lower part of the rectum.

Eudistoma rhodopyge (Sluiter, 1898a). Distoma rhodopyge Sluiter, 1898a

(p. 12, pl. 1 (fig. 2), pl. 3 (figs 5-6)); Michaelsen 1934 (p. 141, and

synonymy). The colonies comprise several lobes arising from a common

base. Without any distinctive character of the zooids, this species has been

recorded from Cape Province to Durban, and from Madagascar, Mauritius

and Mozambique.

Polycitor cuneatus Millar, 1964 (p. 160, fig. 1), has pedunculate colonies raised

above ramified roots. It was only recorded once at 411-450 m depth, off

Durban.

Polycitor nitidus (Sluiter, 1898a). Distoma nitidum Sluiter, 1898a (p. 17). This

species from Durban is not sufficiently described and remains doubtful. It

has not been recollected and Sluiter’s descriptions are often erroneous.

Polycitor psammophorus Hartmeyer, 1912 (p. 300, pl. 38 (fig. 1), pl. 43

(figs 2-3)), off the Agulhas Bank, was described from immature colonies

and was not recorded again. It has a doubtful generic position.

Cystodytes morifer Michaelsen, 1919 (p. 76, fig. 34), from Durban.

Cystodytes roseolus Hartmeyer, 1912 (p. 310, pl. 43 (figs 7-14)), Algoa Bay;

Millar, 1962 (p. 141, fig. 13), Cape Province. The species, distributed from

130 ANNALS OF THE SOUTH AFRICAN MUSEUM

Dakar to the Cape Province and the Seychelles, is characterized by the

peculiar shape of the spicules.

Distaplia capensis Michaelsen, 1934 (p. 141), from the Cape Province, and

found again by Millar (1962: 149, fig. 17; 1964: 168), has a folded stomach

wall and gonads included in the gut loop. The colonies are purplish

gelatinous lobes.

Distaplia durbanensis Millar, 1964 (p. 167, fig. 6), is only known from the type

colony dredged at 411 m depth off Durban. The colony is stalked. The

stomach wall has 40-50 narrow folds or lines of papillae.

Sigillina vasta Millar, 1962 (p. 153, fig. 19), from Cape Province, was dredged

between 62 and 77 m depth.

Family Clavelinidae

Clavelina enormis Herdman, 1880 (p. 725), was described from a single

specimen collected from Simon’s Bay. Herdman’s description is very short

and could apply to any species of the genus. In this colony of only four

zooids, two of them were united by their thoracic tunic, a feature that

Herdman (1882) considered an ‘abnormality’. Later, this same specimen

was named Stereoclavella enormis by Herdman (1891) and Chondrostachys

enormis by Hartmeyer (1909-1911). Some specimens of Clavelina enormis

were described by Hartmeyer (1905) from Mauritius and Zanzibar, and by

Millar (1956), and Monniot, C. & Monniot, F. (1976a) from Mozambique

(Inhaca). Hartmeyer (1912) also described Chondrostachys enormis from

Diego Garcia. All these references probably correspond to the tropical Indo-

Pacific species Clavelina moluccensis (Sluiter, 1904) after Monniot, C.

(1997: 208). A synonymy of Clavelina steenbrasensis Millar, 1955, and

C. enormis remains possible.

Clavelina roseola Millar, 1955 (p. 183, fig. 13), is a species that now belongs to

the genus Stomozoa.

Clavelina steenbrasensis Millar, 1955 (p. 185, fig. 14), known from False Bay

and Mossel Bay, is a species with a colony made of lobes, each consisting

of several zooids included in a common tunic.

Family Didemnidae

Trididemnum natalense Michaelsen, 1920a (p. 3). In the description of the

single colony of this species, the larva is not mentioned. It seems difficult to

distinguish this colony from T. cerebriforme without additional details.

Didemnum karlae Michaelsen, 1920a: 37. This species has never been recorded

again since its collection in an aquarium at Isipingo. The larvae were not

described and the zooids, which were not figured, have no distinctive

character, so the species is hardly recognizable.

Didemnum speciosum asperum Herdman, 1886, is an Atlantic species. Sluiter

(1898a) doubtfully assigned colonies from Durban to this species without

any description. This identification cannot be retained.

SOUTH AFRICAN ASCIDIANS 131

Didemnum stilense Michaelsen, 1934 (p. 146), from Cape Province, was

described as a cartilaginous species, thick and filled with spicules and

bladder cells. The larvae were not described. Millar (1955: 176; 1962: 164)

assigned to the same species didemnids from the same region that were

rather different in shape with variable spicules, zooids and larva. He

mentioned the possible confusion of several different species.

Didemnum velans Michaelsen, 1920a (p. 41). Described from Zanzibar, it was

later recorded in Still Bay (Michaelsen 1934) without additional description.

The species has thin colonies. The larva was not described.

Polysyncraton chuni Hartmeyer, 1912 (p. 326, pl. 43 (figs 22-23)), and

Polysyncraton spongioides Hartmeyer, 1912 (p. 323, pl. 43 (figs 19-21)),

were both collected at 318 m depth off the Cape of Good Hope and not

recorded since.

Leptoclinides capensis Michaelsen, 1934 (p. 151), from Still Bay, was later

recorded in the Cape Province by Millar (1962: 167) and Monniot, F.

(1978) at Kerguelen. The main character of the species is the single testis

vesicle.

Diplosomoides capense Hartmeyer, 1912 (p. 329, pl. 37 (fig. 4), pl. 43

(figs 15-18)), from 318 m depth off the Cape of Good Hope, may be a

Lissoclinum species. As described it has two testis vesicles and a straight

sperm duct, but the funnel-like cloacal siphon directed backwards is

surprising. The species has not since been collected.

Lissoclinum cavum Millar, 1962: 168, fig. 26, from the Cape Province, was

recorded with doubt from Namibia (Turon 1988) and from Madagascar

(Monniot pers. obs.). This species has a rosette of testis lobes.

Family Ascidiidae

Ascidia arenosa Hartmeyer, 1909 (nom. nov. for A. sabulosa Sluiter, 1898a:

45, pl. 5 (figs 2-5)), was described from Durban from a single specimen.

This species, covered with sand, was found again by Millar (1956) at

Inhaca, Mozambique.

Ascidia compta Sluiter, 1898a (p. 43, pl. 5 (figs 19-21), pl. 6 (fig. 1)) was

described from Knysna, from a single young specimen of 10 mm.

Ascidia krechi Michaelsen, 1904a (p. 253, pl. 10 (fig. 8), pl. 13 (figs 59-61)).

A single specimen was dredged off Cape Town (34°33.3’S 18°21.2’E,

318 m).

Ascidia pygmaea sensu Millar, 1955 (p. 189, fig. 17) was recorded from

Knysna. A small animal 1.5 mm long, not described. The figured digestive

tract does not look like that of the type species figured by Michaelsen (1918:

56, fig. 9) from Mauritius. This identification seems doubtful.

Ascidia stenodes Millar, 1962 (p. 172, fig. 27) was recorded from False Bay.

This species has an uncommon shape with a gut in a single loop.

132 ANNALS OF THE SOUTH AFRICAN MUSEUM

Family Agneziidae

Agnezia capensis Millar, 1955 (p. 191, fig. 19) is known from a single

specimen collected in False Bay.

Agnezia glaciata Millar, 1960 (p. 92, fig. 30B), is known from a single

specimen from Table Bay. This small species (11 mm) lives free on sandy

bottoms. Millar (1960), redescribing Agnezia glaciata Michaelsen, 1898,

from Patagonia, considered Agnezia capensis and A. glaciata as synonyms.

Monniot, C. & Monniot, F. (1976b) again recorded specimens of this

species at Inhaca. The distinctions between the different Agnezia species

have been detailed in Monniot, C. & Monniot, F. (1983).

Family Styelidae

Botrylloides nigrum giganteum (Pérés, 1949) was recorded by Millar (1955,

1962) from Durban Harbour, Knysna and Mozambique. Botryllus giganteus

is distinct from B. niger and is known from Senegal and Brazil (Rio de

Janeiro and San Sebastian harbours). This species, probably introduced into

South Africa, is not present in this collection. It differs from all others by its

numerous rows of stigmata (15-19), and a funnel-like stomach with a very

small caecum. Unfortunately, its most original character, the position of the

stomach in a prolongation of the branchial sac, was not indicated.

Alloeocarpa capensis Hartmeyer, 1912 (p. 261, pl. 38 (fig. 2), pl. 41

(figs 16-18)) was described from St Francis Bay (34°05’S 17°52’E, 267 m),

and recorded by Millar (1962: 182, fig. 31) from Algoa Bay at 31 m, and

off Lion’s Head, Cape Peninsula at 248 m. This species is characterized by

gonads on the right side only, and the ovary situated posterior to the testis.

Polyzoa falclandica Michaelsen, 1900. Hartmeyer (1912: 258, pl. 41 (figs 13-

15) recorded this species from St Francis Bay. This species is considered a

synonym of Polyzoa opuntia Lesson, 1830. Hartmeyer’s description of the

single specimen does not correspond to the definition of the genus. A con-

fusion with Alloeocarpa capensis from the same station remains possible.

Metandrocarpa fascicularis Millar, 1962 (p. 183, fig. 32) described this species

from 8 miles off Cape St. Blaize at 72 m. The characteristics of this species

are discussed with regard to M. asymmetra.

Metandrocarpa tritonis Michaelsen, 19046 (p. 240, pl. 10 (fig. 2), pl. 13

(figs 55-57)) was described from Plettenberg Bay at 100 m. The only zooid

collected is nevertheless like that of a colonial styelid genus. It is

characterized by the presence of branchial folds and gonads made of a single

testis covered by an ovary. All other species of the genus are tropical.

Oligocarpa skoogi Michaelsen, 1923b (p. 3, figs 1, 2). The species is known

only by two specimens attached together. The external aspect is very similar

to Styela canopus. The genus Oligocarpa is characterized by a single gonad

on the left side; it is sometimes considered colonial but generally solitary

individuals are found. Two species are known: one from South Africa, the

other from Kerguelen.

SOUTH AFRICAN ASCIDIANS 133

Polyandrocarpa durbanensis Millar, 1952 (p. 197, fig. 25) was described from

Durban. Plante & Vasseur (1966: 150, pl. 4 (figs 31-32)) recorded it from

Madagascar, Tulear Harbour. The zooids are small, 6 mm, naked, and

united by stolons. They have three well-formed branchial folds and a

rudimentary fourth fold. Three to six gonads are aligned on the left side and

4-7 on the right side. A single endocarp lies in the gut loop.

Polyandrocarpa placenta (non Herdman) Millar, 1955 (p. 199, fig. 26) was

recorded from False Bay in 28 m. In the single colony, the salmon-pink

zooids are agglomerated in a common tunic. There are four branchial folds

and 6-8 gonads in a line on each side.

Polycarpa (Sluiter, 1898a). Styela (Polycarpa) anguinea: Sluiter, 1898a (p. 52

pl. 6 (figs 15-19)) was recorded from Knysna; and Polycarpa anguinea:

Millar, 1952 (p. 203, fig. 28) from False Bay and Knysna.

Polyandrocarpa anguinea: Millar, 1962 (p. 186) was recorded from Mossel

Bay, Algoa Bay, and Mozambique. This species is said to be present in all

warm seas worldwide. Generally it has aggregated individuals with an

extremely brittle body wall, without endocarps. The gonads in a line on each

side are suspended between the body wall and the branchial sac.

Styela (Polycarpa) natalensis Sluiter, 1898a (p. 50, pl. 6 (figs 11-14)) was

described from Isipingo. Polycarpa natalensis has also been recorded by

Millar (1961: 14, fig. 2) from Mozambique, and by Monniot, C. &

Monniot, F. (1976a: 374, fig. 3B) from Inhaca, Mozambique. This small

species, 5-15 mm across, differs from other South African species of

Polycarpa by numerous endocarps distributed on the entire internal surface

of the body wall.

Cnemidocarpa psammophora Millar, 1962 (p. 188, fig. 34) was described from

Algoa Bay, 25-39 m. This small species is covered with sand, with tunic

hairs anchoring it on the sandy bottom. It has 5-8 gonads on the left and

10-11 on the right side.

Cnemidocarpa radicata (Millar, 1962). Styela radicata Millar, 1962 (p. 191,

fig. 35) was described from Mozambique, 2 m, and also recorded by Millar

(1964: 174) from the same region. As Cnemidocarpa radicata, the species

was also recorded by Monniot, C. & Monniot, F. (1976a: 368, fig. 2A)

from Inhaca Island, Mozambique. The holotype is the only specimen of this

species recorded in southern Africa. It has a single small endocarp on the

left side of the body. The type specimen is a juvenile and the proximity of

male and female gonads, which is a characteristic of the genus

Family Pyuridae

Boltenia africana Millar, 1962 (p. 198, fig. 40) is known from Mossel Bay and

Algoa Bay in 9-22 m. This species is easy to identify, with its transverse

stigmata. It is the only shallow-water species of the genus in the Southern

Hemisphere.

134 ANNALS OF THE SOUTH AFRICAN MUSEUM

Hartmeyeria bouilloni Monniot, C. & Monniot, F., 1976a (p. 390, text-fig. SB,

D, pl. 6) was described from Mozambique. This species was erroneously

identified as Microcosmus pedunculatus Pérés, 1951, by Millar (1962: 197,

fig. 39) from Mossel Bay (12 m) and Mozambique (2 m). This sandy species

has a peculiar aspect with the body slightly laterally flattened, and encircled

by a tunic crest extending along the dorsal and ventral line. There is a long

naked peduncle arising from the middle of the ventral side.

Microcosmus albidus Michaelsen, 1904a (p. 213, pl. 10 (fig. 4), pl. 11 (figs 25,

26)). This species is known by a single specimen 11 x 8 mm across from

100 m depth off St Francis Bay. The gut and gonads are not figured. This

species has six branchial folds.

Microcosmus trigonimus Millar, 1955 (p. 212, fig. 37). This species with eight

branchial folds was only recorded from Durban; the number of specimens

was not stated. The main characteristic is the presence of two gonads on the

left side of the body side, one of them exterior to the intestinal loop.

Family Molgulidae

Eugyrioides myodes (Millar, 1962). Eugyra myodes Millar, 1962 (p. 206,

fig. 44) was described from two specimens from Algoa Bay, in 17-18 m.

This species, 11 mm in diameter, is covered with sand, has seven longi-

tudinal branchial vessels on each side, a secondary gut loop not well

marked, and obvious transverse muscles. In the genus Eugyrioides there is a

gonad on the left side that is absent in the genus Eugyra.

Pareugyrioides macrentera (Millar, 1962). Eugyra macrentera Millar, 1962

(p. 209, fig. 45) was described from a single specimen from Algoa Bay, in

8-10 m. Pareugyrioides macrentera Monniot, C. & Monniot, F., 1976a

(p. 387, figs 6B, 8) was also recorded from Inhaca Island, Mozambique.

This species, covered with sand, is characterized by a long digestive tract

deeply curved on itself, enclosing the left gonad. According to Millar

(1962), the holotype is a juvenile with a non-fully developed branchial sac,

but the larger specimen from Mozambique has the same structure, which

distinguishes the species as belonging to the genus Pareugyrioides.

ACKNOWLEDGMENTS

We are indebted to the following museums for making some type specimens

available: the British Museum, the Zoologisch Museum in Amsterdam, the

Museum ftir Naturkunde der Humboldt Universitat zu Berlin, the Senckenberg

Institut in Frankfurt, the Smithsonian Institution, the Seto Marine Biological

Laboratory, the National Science Museum in Tsukuka, Japan, and the South

African Museum. C. Monniot’s travel to South Africa was funded by the

Museum national d’Histoire naturelle. Financial support and the cost of

the colour plates were met by a National Research Foundation grant to

C. L. Griffiths. We wish to thank Madeleine Martin for her help in the

preparation of the manuscript. We are very indebted to Prof. Todd Newberry

for his remarks and careful reading of the manuscript.

SOUTH AFRICAN ASCIDIANS 135

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MonnioTt, C. 1981. Apparition de l’ascidie Microcosmus exasperatus dans les ports

méditerranéens. Tethys 10 (1): 59-62.

MonnioT, C. 1987. Ascidies de Nouvelle Calédonie. IJ. Les genres Polycarpa et

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275-310.

MonnioT, C. 1988. Ascidies de Nouvelle Calédonie. IV. Styelidae (suite). Bulletin du

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MonnioT, C. 1991. Ascidies de Nouvelle Calédonie. X. Stolidobranches (suite). Bulletin

du Muséum National d’Histoire Naturelle, Paris (4) 13 (1-2): 3-37.

MonnioT, C. 1994. Pyura lignosa (s.s.) a Pacific ascidian from Central America, with

descriptions of species confused under this name. Zoological Journal of the Linnean

Society 110: 41-51.

MonnioT, C. 1997. Les genres Archidistoma et Clavelina (Ascidiacea, Clavelinidae) dans

le canal du Mozambique. Zoosystema 19 (2-3): 193-209.

MonnlioT, C. & BITAR, G. 1983. Sur la présence de Pyura stolonifera (Tunicata,

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MonnlioT, C. & MonnioT, F. 1976a. Ascidies de la céte du Mozambique. Revue de

Zoologie Africaine 90: 357-392.

MonnioT, C. & MONNIoT, F. 1976b. Quelques ascidies bathyales et abyssales du sud-est

pam: Bulletin du Muséum National d’Histoire Naturelle, Paris (3) Zoologie 269:

71-680.

MOonnioT, C. & MonnioT, F. 1983. Ascidies antarctiques et subantarctiques: morphologie

et biogéographie. Mémoires du Muséum National d’Histoire Naturelle, Paris (A) 125:

168 pp., 7 Pl.

MonnioT, C. & MonnioT, F. 1987. Les Ascidies de Polynésie francaise. Mémoires du

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SOUTH AFRICAN ASCIDIANS 139

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Nouvelle-Calédonie. Diversité des stratégies adaptatives. In: CROSNIER, A. ed. Résultats

des campagnes MUSORSTOM 8. Mémoires du Muséum National d’Histoire Naturelle,

Paris (A) 151: 357-448.

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three new species. Journal of Natural History 31: 1623-1643.

MonnioT, F. 1969. Sur une collection d’ascidies composées de Dakar. Bulletin du Muséum

National d’Histoire Naturelle, Paris (2) 41: 426-457.

MonnioT, F. 1978. Quelques Didemnidae et Polycitoridae (Ascidiacea) de Kerguelen.

Annales de |’Institut Océanographique, Paris 54 (2): 163-170.

MonnioT, F. 1983. Ascidies littorales de Guadeloupe. I. Didemnidae. Bulletin du Muséum

National d’Histoire Naturelle, Paris (4) 5A (1): 5-49.

MonnioT, F. 1987. Ascidies de Nouvelle-Calédonie. III. Polyclinidae du lagon. Bulletin

du Muséum National d’Histoire Naturelle, Paris (4) 9A (3): 499-535.

MonnioT, F.’ 1989. Ascidies de Nouvelle-Calédonie VII. Les genres Atriolum et

Leptoclinides dans le lagon sud. Bulletin du Muséum National d’Histoire Naturelle,

Paris (4) 11A (4): 673-691.

MonnioT, F. 1990. Ascidies de Nouvelle-Calédonie. VIII. Le genre Trididemnum. Bulletin

du Muséum National d’Histoire Naturelle, Paris (4) 12A (3-4): 517-529.

MonnioT, F. 1992. Ascidies de Nouvelle-Calédonie. XII. Le genre Lissoclinum

(Didemnidae) dans le lagon sud. Bulletin du Muséum National d’Histoire Naturelle,

Paris (4) 14A (3-4): 565-589.

MonnioT, F. 1994. Ascidies de Nouvelle Calédonie. XV. Le genre Didemnum

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299-344.

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Annales de |’Institut Océanographique, Paris 54 (2): 139-162.

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Korean Research Institute for Better Living 33: 99-136.

140 ANNALS OF THE SOUTH AFRICAN MUSEUM

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new genus and family of ascidians from the coast of California. Mark Anniversary

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RITTER, W. E. 1913. The simple ascidians from the northeastern Pacific in the collection of

the United States National Museum. Proceedings of the United States National Museum

45: 427-505.

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tunicate common to southern Brazil and New-Caledonia. Annales de 1’Institut

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Zoologische Anzeiger 23: 110.

SLUITER, C. P. 1904. Die Tunicaten der Siboga-Expedition I. Die socialen und holosomen

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SLUITER, C. P. 1905. Tuniciers recueillis en 1904 par M. Ch. Gravier dans le golfe de

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and Development 33 (1): 11-23.

rrge)

}

Lie

6. SYSTEMATIC papers must conform to the /nternational code of zoological nomenclature

(particularly Articles 22 and 51).

Names of new taxa, combinations, synonyms, etc., when used for the first time, must be followed

by the appropriate Latin (not English) abbreviation, e.g. gen. nov., sp. nov., comb. nov., syn. nov.,

etc. The name of the taxon should be followed, without intervening punctuation, by the author’s name

(not abbreviated) and the year of publication; a comma must separate author’s name and year. The

author’s name and date must be placed in parentheses if a species or subspecies is transferred from its

original genus. The name of a subsequent user of a scientific name must be separated from the

scientific name by a colon.

Synonymy arrangement should be either according to chronology of names, i.e. all published

scientific names by which the species previously has been designated are listed in chronological order,

with all references to that name following in chronological order (see example 1), or according to

chronology of bibliographic references, whereby the year is placed in front of each entry, and the

synonym repeated in full for each entry (see example 2). The author should adopt one style or the

other throughout a paper.

Family Nuculanidae

Nuculana (Lembulus) bicuspidata (Gould, 1845)

Figs 14-15A

Example 1

Nucula (Leda) bicuspidata Gould, 1845: 37.

Leda plicifera A. Adams, 1856: 50.

Laeda bicuspidata (Gould) Hanley, 1859: 118, pl. 228 (fig. 73). Sowerby, 1871, pl. 2 (fig. 8a—b).

Nucula largillierti Philippi, 1861: 87.

Leda bicuspidata (Gould): Nicklés, 1950: 163, fig. 301; 1955: 110. Barnard, 1964: 234, figs 8-9.

Note punctuation in the above example: comma separates author’s name and year; semicolon separates more than

one reference by the same author; full stop separates references by different authors; figures of plates are enclosed in

parentheses to distinguish them from text-figures; dash, not comma, separates consecutive numbers.

Example 2

1845 Nucula (Leda) bicuspidata Gould, p. 37.

1856 Leda plicifera A. Adams, p. 50.

1859 Laeda bicuspidata (Gould) Hanley, p. 118, pl. 228 (fig. 73).

1861 Nucula largillierti Philippi, p. 87.

1871 Laeda bicuspidata (Gould): Sowerby, pl. 2 (fig. 8a—b).

1950 Leda bicuspidata (Gould): Nickleés, p. 163, fig. 301.

1955 Leda bicuspidata (Gould): Nicklés, p. 110.

1964 Leda bicuspidata (Gould): Barnard, p. 234, figs 8-9.

In describing new species, one specimen must be designated as the holotype; other specimens

mentioned in the original description are to be designated allotype (if applicable) and/or paratypes;

additional material not regarded as paratypes should be listed separately. The complete data

(registration number, depository, description of specimen, locality, collector, date) of the holotype

and paratypes must be recorded, e.g.:

Holotype. SAM-A13535 in the South African Museum, Cape Town. Adult female from mid-tide region, King’s

Beach, Port Elizabeth (33°51’S 25°39’E), collected by A. Smith, 15 January 1973.

Note standard form of writing South African Museum registration numbers and date.

7. SPECIAL HOUSE RULES

Capital initial letters

(a) The Figures, Maps and Tables of the paper when referred to in the text, e.g. ‘. . . the Figure depicting

C. namacolus ...’, or ‘. . . in C. namacolus (Fig. 10). . .’

(b) The prefixes of prefixed surnames in all languages, when used in the text, if not preceded by initials or full

names: e.g. Du Toit, but A. L. du Toit; Von Huene, but F. von Huene

Punctuation should be loose, omitting all not strictly necessary. Reference to the author should

preferably be expressed in the third person. Roman numerals should be converted to arabic, except

when forming part of the title of a book or article, e.g. ‘Revision of the Crustacea. Part VIII.

Amphipoda.’. A specific name must not stand alone, but be preceded by the generic name or its

abbreviation to initial capital letter (except at the beginning of a sentence or paragraph), provided the

same generic name is used consecutively. The name of new genus or species should not be included

in the title; it should be included in the abstract, counter to Recommendation 23 of the Code, to meet

the requirements of Biological Abstracts.

8. GENERAL. Once referees’ reports have been received by the editor, these will be discussed by the

editorial committee. If the paper is considered acceptable after minor or major revision, the reports

will be forwarded to the author who must then thoroughly revise in accordance with the referees’

suggestions. Final acceptance of the revised manuscript will be considered by the editorial committee.

In the case of major revision being necessary, the committee reserves the right to consult one or more

referees regarding the revised manuscript.

TT,

3 9088 01206 7237 |

CLAUDE MONNIOT, FRANCOISE MONNIOT

CHARLES L. GRIFFITHS

MICHAEL SCHLEYER

SOUTH AFRICAN ASCIDIANS

E SOUTH AFRICAN

a MUSEUM

CAPE ‘TOWN

INSTRUCTIONS TO AUTHORS

1. MATERIAL should be original and not published elsewhere, in whole or in part.

2. LAYOUT should be as follows:

(a) Centred masthead to consist of: title: informative but concise, without abbreviations and not including the names of

new genera or species; Author’s(s’) name(s); address(es) of author(s) (institution where work was carried out);

number of illustrations and tables

(b) Abstract of not more than 200 words, intelligible to the reader without reference to the text

(d) Introduction

(e) Subject matter of the paper, divided into sections to correspond with those given in table of contents

(f) Summary (if paper is lengthy)

(g) Acknowledgments

(h) References

(i) Abbreviations, where these are numerous.