BULLETIN OF MARINE SCrENCE. 62(1): 1-6. 1998

SPECIES OF (ASCIDlACEA) FROM SOUTH VIETNAM

Lin.da Cole and Maria Vorontsova

ABSTRACT Four species of the family Pyuridae from SOUdl Viemam are listed and discussed, widl habitat and breeding nOles added.

Thi is the second contribution to the ascidian fauna of Vietnam from the specimens that were collected by M. Vorontsova from Jline 1989-June 1991. never before coUected from South Vietnam provided the opportunity to augment the descriptions of four previously described pecies of Pyuridae. The area tudied was Bing Cang Bay south to Cam Ranh Bay (Fig. I). Five species from the family Pyuridae were coUected: exasperatus Hellel~ 1878; momus, 1816; curvigona Tokioka, 1950; Pyura shiinoi Tokioka, 1949 and Pyura camranica (Vorontsova and Cole, 1995). P. camranica was described by the authors previously, the other four species are discussed in this work. Breeding notes were only made on M. exasperatus and H. momus, the two most common species.

Microcosmus exaspera.tus Heller, 1878 Figures 2A-E

For earlier records, see Van Name. 1945. For synonyms, see KOll, 1985: 348: Monniot, 1989. fig. 2. pI. I. p. 479. ten-a tipiea: New South Wale

Material £xamined.-AII from SOUdl China Sea, Cam Ranh Peninsula. 12/I1I-1990. (USNM 20115), from wharf on the middle of the west shore of peninsula, substrate: metal, dep. 0-4 111. IflII-1990, (USNM 20116), from bridge between peninsula and mainland. surface: metal. dep. 0- 4m. 4/IIJ-1990, (US M 20117). from bridge between peninsula and mainland, surface: metal. obrained larvae by anifieial fertilizaiion. In Soutb Vietnam, M. exasperatus was usually found in aggregations or cluster with other ascidians or attached to various other invertebrates. Only once was this species collected from a natmal substrate. M. exasperatus was found in large quantities among the fouling communities that were attached to the metallic sup- port or legs of the bridge that connects Cam Ranh Peninsula and the mainland of South Vietnam and in large quantities on the wharf located approximately 6 kIn. south of the bridge. On the bridge, M. exasperatus wa found inside thick colonies of Eudistoma sp. that were sometimes up to 6 cm thick. Only the four lobed bright orange iphon of M. exasperatus could be 'een protnlding from the tunic of the olive colored colonies of Eudistoma, the rest of the tunic of M. exasperatus is beige to light brown in color and thinly covered with algae and mud. Individuals were approximately 3 cm in length. In South Vietnam, the breeding season of this species starts around the middle of February and lasts until the middle of April. Mature eggs were approximately 350 tJ-m.Larvae were easily obtained by artificial fertilization. It takes 10-11 h for a larva to hatch after fertilization of an egg. Lal:-vae were small, usually 800 tJ-ffiin length with a trunk of 280 f-Lm. Upon hatching, definitive organs are not 2 BULLETIN OF MARl 10SCIENCE. VOL. 62. NO. I. 1998

12'

.& PYllrlJo eurvioonlll v UIC;rOCQlllmUIIl eX88lHHIIltua

• P)'urlll ."""(11

109- 10' 100" 2Q'

Figure I. The vicinity of Nytha Trang. Vietmlm. Localities (symbols) show place specimens were collected. Map on right is an enlargemem of area Illost studied.

yet developed; the larvae bas only a statocyte, the ocellus is absent. According to laboratory observation, the larvae can swim up to 24 h before settling on a ubstrate (Vorontsova, 1992). A typical specimen from Vietnam consists of a branchial lining that has sharply pointed siphonal armature (55 /-lm in length) in the upper third of its lining (Fig. 2E,F). which are approximately 250 /-lm in length and 75-250 I-Lffi wide. The lower part of the siphonallining contains threadJike filaments that are usually 500 fJ-m in length. The dorsal tubercle is quite large. The slit is V-shaped and pro- truding, with horns that spiral inward several times. There are eight wide folds on each side of the branchial sac, with 6-7 tigmata per mesh. The hepatic gland (liver), brain like with papiJIae (Fig. 2B), has two small lobes (Fig. 2A). Gonads are divided into three sections, with one section enclosed in the gut loop.

B

Figure 2. MicrocosIllU.\· ~xa.rperalu.I'. Left view of (A) showing gllt loop; (B) enlargement of hepatic gland showing structure of the gland. COL· A I) VOR NTSOVA: SOUTH VIETNAM T NI ATr,$ 3

Herdmania mOll1us (Savigny, 1816)

Cylllilia /I/(J/lHI.~ Savigny. j 816. p. I·n. pI. I. fig. _. pI. 4. fig. I; Nerdllu/Ilia 1/lO/IlIIS Van arne. 1945. p. 341

Mal 'rial Exalllilled.-a. Vietnam. omh China Sea. ha Trang Bay, col. M. Voroms va:

17/1-1990. Sl. 4. Tam Island. coral reef al Ihe . side of island. 1 spec. 17/1-1990.51. 13, east side of M I Island. between branches of single coral "bushes," divided by sand spaces. dcp. 3-4 m. I spec. 16/11-1990, (USNM 20122), Sl. 15. north bank of the Bay on southern pari of Tre Island, on the upper and lower side, of dead flat corals. dep. 1-3 m, 9 spec. 23/11-19( O. (U M 20120). 51. 4. Tam Island. coral reef at the Ilonh side of island. 3 sp"c. 26fV-1990. (US M 20118). s. 6. Shang Lou. ollected during low tide (-2 lll). under flaI stoncs. 15 spec. b. Vietnam. soulh hina Sea. Cam Ranh. col. A. Gogolev and M. Vorontsova: 1111-1990, ( SNM 20119). bridge, in fouling community. 2 spec. 12/lII-1990. (USNM 20121). wharf. fouling comlllunity. dep. 0-4 m, 2 spec.

Thjs pecie wa. one of the most abundant of the sp cies tudied in this area. 1 was found to be equally occurrent in natural habitats and artificial substrate. In natural habitat such a. large stone (up to 40 ern) or dead tubular Acropora colonies which seemed to be a preferred substrate for several ascidian pecies in the region, it was collected from five stations in Nha Trang Bay. In every tation, animal were found attached to the undersides of the ub trate. In Cam Ranh, H. mOl/'ltls was collected from the same artificial substrates at the exact ame place on the ubstrates tha M. exasperafu$ was found. In Cam Ranh, H. momus grow fairly large on artificial ubstrates, up to 9 cm in diam ter; whereas on natural substrates in Nha Trang Bay, this species never gets any larger than 3.5 cm. The tremendous growth on artificial ubstrat i probably due to the excellent water current conditions for ascidians bringing good upplies f oxygen and nutrition into Cam Ranh Bay. Cam Ranh Bay is shaUow and rich with phyto and zoo- plankton. Tide currents are strongest in tbe narrowest part of th bay where the bridge is located. The breeding season starts around the middle of December and lasts untiJ around the middle of April. There is a second shorter breeding season which takes place around the middle of July through mid August. Eggs ar'e large (approxi- mately 480 J.Lm) and orange. It rakes th larvae app1'OximateJy 14 h to hatch after the egg is fertilized. Larvae were found to be approximately 1400 J.l.min length with a trunk of 400 J.Lm, sen ory organs consists of an otoUth and ocellus with three len e . Siph ns opened 7 d after settlement. H. momllS i a welllcnown tropical species. The specimens collected w re round or oval shaped and attached by the ventral or ventro-lateral surface, siphons are terminal. Small specimens up to 4 cm) are light pink in color the larger ones are gray to brown. The mantle is pinkish red. The tunic of smaller pecimens is thin (2 nun or less) and almost transparenI and allows the mantle to be seen thus givi.ng the pinki h coloring in smaller individuals. A 'pecimens get larger the tunic becomes thicker up to 4 or 5 mm) and translucent and are often covered with other epibionts (algae, hydroide , colonial ascidians, etc.). An interesting thing to note is that the typica110ng spicu1es of this species, which are distributed in the tunic as we1l a in the ti sue resemble mantle mu culature in fre hly dissected material when observed under low magnification. In the branchial sac, there are eight folds on the left and eight on the right witll 6-7 stigmata per mesh on the fiat between folds. The stomach is narrow and elongated. The hepatic gland is large, elongated and unbranched, with numerou' tubules. The gonad' are lo- cated on both sides of the body and ar-e large and elongated. 4 BULLETIN OF MAIIINE S noNCE. VOL. 62. NO. I. 199M

Figure 3. Pyura clIl1lig(ma. (Al entire animal .mached to coral; (B) left view of dissected animal showing gut loop: (C,D) Iwo differenl dorsal tubercles.

Pyura curvigona Tokiaka, 1950 Figure 3

Tokioka. 1950: p. 147, fig. 22; pI. 10 figs. 4-6 967: p. 199-202, figs. 88---89 Palau lsI. Tokioka 'I/lel ishikawa. 1975. p. 339-340, figs. 37-40 (Hong Kong) Millar. 1975, p. 312-314. figs. 90-91 (Indonesia) Nishikawa, 1980. p. 101 (only listed) Kon and Goodbody, 1980. p. 539, pI. 3d (note, Kon. 1985) ishikawa, 1984, p. 136 (Truk Isl.). Kon, 1985, p. 296-299 (West. Auslrali<:t; Qucensland: Lizard)

Material £xwllilled.-17/1V-1990 (4)-Solllh China Sea. Nlla Trang Bay, Trc lsI.. corol! rcef, under flat slone. del'. ] .Sm

16/11-1990 (US M 20123),15 spec.-Soulil China Sea, Nh •• Tnlllg Bay. 110lth bank 0 the bay on southern part of Tre lsI. on upper sidc of lubular coral, del'. 3m. As mentioned by Kott (1985), this beautiJul tropical we tern Pacific species ha been recorded on very few occasions. Two specimens were found in Vietnam that for the most part fit the previous descriptions of P. curvigon.a: Tokioka 1950, 1967; Tokioka and Nishikawa. 1975; MiUar 1975; Nishikawa, 1984, and Kott, 1985. When pre erved, specimens from Vietnan1 are white-beige and reddish around and inside of the siphons and not chocolate brown as noted by Tokioka and Nishikawa (1975). Siphonal armature (spines) is of the typical Pyura form but the armature extends out of the iphonal lining and are more numerous near the siphons and less numerous ventrally. Spines were not numerous in the specimen (USNM 11405) examined by Tokioka (1967) from Palau. Spicules are omewhat more dense within the wrinkles of the test. Vietnamese species have the typical green irridescence at COLE AND VORONTSOVA: SO TI·j VIETNAM TUN ICATES 5

B

Figure 4. PYIIW sl1iilloi. (A) entire animal: (B) lllunLlc 1ll.lsculalUre. the bases of the spine that most P. curvigona have, but a red color was observed when light pas ed through the bases of the 'pines. The length of the spines differ, ranging from approximately 60-140 /-Lill. Tentacle branching is of two orders. In one of the specimens examined from Vietnam, the slit in the dorsal tubercle wa U- shaped with lightly cW"ved ends; in another, the slit was not a perfect V-shape (Fig. 3C,D). In the branch:ial sac, there are six folds on each side with 4-7 stigmata per mesh. Endocarps were noted on the outside and inside of the gut loop. The hepatic gland is not divided into the smalJer anterior and larger posterior portions noted previously. In the specimen from Vietnam, the authors noted brushlike branchings along the intestine (Fig. 3B). Gonads consist of typical genital cap ules and the anal margin consists of six deep square lobes.

PYL/ra shiinoi Tokioka, 1949 Figure 4 ?Pyura .,·l1ii"oi Tokioka, 1949. fig. 14.-Jup'lI1 PYlira sp. aff. lig//(}sa Tok.ioka. 1970. p. 103-106. 11g. I I.-Philippines. PYII/'Gligllosa Nishik,\wa and Tokioka, 1976., p. 398-399, fig. 7, 50-52; Nishikawa, 1980 tab. I; 1982b. p. 204; 1984a. p. 136; 1984b. p. 151; 1986b, p. 176.-J'lpan PYlira sp. cf. Iigno.I'" Nishikawa. 1991. p. 133-137, fig. 34.-Sea of hlP,1I1 Material Exalllined.-161J[-1990. Vietnam. Soulh hina Sea. Nha Trang Bay, nonh bank of the bay all sOllthern part of HOIl Tre [sl.. on the upper and lower sides of dc,lCl Aut corals, dep. 1-3 m, col. M. Voront~o",'- Tunic is red and cartilaginous, thinner on ventral portion. The entire ventraJ side is flattened. The test extends slightly to reach the surface of attachment (Fig. 4A). The body is flattened dol' a-ventrally. Both iphons are on the dorsal side. Animal j easily removed from the tunic. Siphons protrude and there is a siphonal sphincter muscle. There are red and white stripes in the atrial as well as the branchial siphonal Lining. The red and white coloration of the siphonal lining is absolutely the same as in P. cam.ranica (Vorontsova and Cole, 1995). The iphonal armature (spines) is also guite similar to tJ1at of P. camranica, but slightly thicker. Under the sipbonal sphincter muscle there are 12 simple branched tentacles of three izes. Only branching of the first order was noted. Each of the transparent tentacles has yellowish pots in ide. The dorsal tubercle is separated from the ten- tacles and has a horse-sh e shaped slit. Fr m the dorsal tubercle extends a very long ganglion (4 mm). The dorsal lamina begins arow1d the middJe of the ganglion. The dorsal languets are thin, narrow and long, e pecially those closest to the esophagus. The branchial sac is irregular in most places. It is very thin and consists of seven 6 8ULLETIN OF MARINE S II:NCE. VOL. 62. NO. I. 1998

folds with large stigmata, three to six per m sh. The parastimatic vessels are of two orders: first ves els cross the stigmata and are very narrow; the second type varies from nalTOWto sometimes wide and flat. The gut loop is elongated with an unlobed anal opening. The hepatic glaJld is well developed and consists of at lea t two lobes. Unfortunately, our specimen was damaged and the complete lobe count could not be made. There were a few endocarps on the gut loop (Fig. 4A). According to Monnior's revision of Pyura lign.osa, that places Nishikawa's spec- imens (Nishikawa, 1991) under the genus shiinoi, our specimens from South Viet- nam, should be classified as Pyura shiinoi. The inner features of our specimens are quite similar to those of specimens that Nishikawa described as Pyura p. cf lignosa: and our South Vietnamese specimens fit Tokioka's 1949 descliption of Pyura shiinoi. The authors noted siphonal armature in the specimens from South Vietnam. This was not previously noted by Tokioka because his pecimens lacked tunics.

ACKNOWLEDGMENTS

We wish 10 thank the staff of The Soviet- Vielnamese Tropical Celller for making the facilities available. We are also Llmnkful for F. M. Bayer's USNM) attention and literary assistance. We are gnlteful for the financial support given to M. Vorolllsova from The Smithsonian Institution's Office of Fellowships and Grants and from The Georgc Soros International Science Foundation.

LITERATUR - CITED Hcller, C. 1878. Beitrage zur nahem Kennrniss der Thnicalcll. Sit-zbel; Akad. Wiss. Wien 77: 83-11 Q. Huus, J. 1927. Ueber die ausbreitungshindernisse. u. Vcrbreitung der Ascidien. yt. Mag. aturvid 65: 153-l74. Kott, P. 1985. The Australian . Pm1 L Phiebobranchia and talidobranchia. Mem. Queensland Mus. 23: 1-438.

Kott.P. and 1. Goodbody. 1980. The ascidian. of H ng Kong. Vol. I. Pages 503-554 ill B. S. Monon. C K. 1:eng. eds. Proc. First [nL'1. Mar. BioI. Workshop: TIle flora ,1Ild fauna of Hong Kong and Southern China. Hong Kong Univ. Press. Millar, R. H. 1975 Ascidians fTOIll the Indo-Wesl Pacific region in the Zoological Museum, Copenhagen. (Tunicma, Ascidiacea). Stecnstrupi" 3: 205-3 36. MonniOl. C. 1989. Ascidies de Nouvelle-Caledonie VI. PYlJndile et MolglJlidae. Bull. Mus. Natn. His!. at. Pari. 4 ser. 11 sect A: 475-507. ---. 1994. PY/ira lignosCi (s.s.). a Pacific ascidian from Central Amelica. widl descriptions of .pecies confused under Lhis name. Zool. J. Linn. Soc. 110: 41-51. Nishikawa, T. 1980. Ascidians from the c aSI of Kii Peninsula middle Jnpan, with description of two new species. Mem. Natn. Sci. Mus. Tokyo 13; 97-111. ---. 1984. Ascidians from the Truk Island. Ponape Island and M"juro AIOI (Tunicma. A. Ascidiacea). Proe. Jap. Soc. SYSL Zool. 27: 107-140. ---. 1990. The ascidians of the Japan Sea I. Publ. Seta Mar. Bioi .. L.lb 34: 73-148. ---. 1991. TIle ascidian or the Japan Sea. U. Publ. Sew Mar. Bi I. Lab. 35: 25-170. --- and T Tokioka. 1976. Contribution to dle Japanese ascidian fauna XXVITl. Ascidians from the Amani lslands. Publ. Seta Mar. BioI. Lab. 22: 377-402. Savigny, J. C. 18]6. Memoires sur Ie animaux s(lIld venebres 2: 1-260. Paris. Tokioka, T 1949. Contribution 10 Japanese ascidian faunu II. NOles on some ascidians collected ehief1y along LllCcoast of Kii Peninsula. Publ. Sew Mar Bioi Lab I; 4-46. 1950. Ascidians from dle Palao Islands. Publ. Seta Mar. Bioi Lab 18: liS-ISO. ---. 1967. Pacific tunicata of the United States National Museum. Bull. USNM 251: 1-247. ---. 1970. Ascidians from Mindoro Island. the Philippines. Publ. Sew Mm·. BioI. Lab. 18: 75--107. --- and T. ishikawa. 1975. COnlriblltion w Japanese ascidian fauna XXVII. Some ascidians from Okinawa. wiLh notes on small collection from Hong Kong. Publ. Scta Mar. BioI. Lab. 22; 325-341. V,m Name, W. G. 1945. The NorLll and South American ascidians. Bull. Am. Mus. at. Hist. 84: 1-476. Voronrsova, M. 1992. Study of a,cidian fauna of Nha Trang BlIY. Proe. irst Sci. Com. Russ-Viet. Trop. Cent. I: l65-168. (in Russian) --- and L. Cole. 1995. A new species of Pyura (Aseidiacea) from South Vietnam. Bull. Mar. Sci. 56: 312-318.

DATE ACCEPTED; July 9. 1996.

ADDRESS: Deparllllelll oJ Jllvenebrelle Zoology. NaiiOlICl/ Museu/II oj Narl/red HislOry. SlOp /63. Smilhsolliall !lwillliioil. Wasllillf!lOll. D. C. 20560.