New Records of Three Styelid Ascidians (Order: Stolidobranchia) to Indian Waters from Andaman and Nicobar Islands

Indian Journal of Geo Marine Sciences Vol. 47 (08), August 2018, pp. 1665-1671

New records of three styelid ascidians (Order: Stolidobranchia) to Indian waters from Andaman and Nicobar Islands

Jhimli Mondal*, C. Raghunathan & Tamal Mondal Zoological Survey of India, Port Blair-744 102, Andaman and Nicobar Islands, India *[Email: [email protected]] Received 11 November 2016; revised 06 April 2017

The present paper deals with three species of styelid ascidians such as Polycarpa papyra Kott, 1985 in which no endocarp found in the gut loop whereas, numerous small endocarps are present in the body wall, Polycarpa argentata (Sluiter, 1890) in which gonads arrangement is confined in the ventral half of the body with large flat topped endocarp enclosed in the gut loop and Symplegma rubra Monniot, 1972 characterized by a red ring encircled both the siphons, which are reported for the first time to Indian waters from Andaman and Nicobar Islands.

[Keywords: Styelidae; New record; Andaman and Nicobar Islands]

Introduction are solitary and Symplegma rubra Monniot, 1972 is The ascidians under the Family Styelidae belong to colonial in nature and all are new record to Indian the Class Ascidiacea and Order Stolidobranchia waters. The morphological and anatomical features represent both solitary and colonial species1. Colonial along with the distribution of these three newly members of this family are diverged as they represent recorded styelid ascidians are given in detail. zooids embedded in common test and form encrusting sheet like structure while on the other hand zooids can Materials and Methods be connected by only stolons2,3. Some members of Andaman and Nicobar Islands comprised of 572 this group are aggregated such a way that they can be islands, islets and rocky out crops of the low thought as colonial species but they do not have any mountain chain. This region has enriched biodiversity connections among them2,3. Literatures on ascidian with the various marine and terrestrial ecosystems. fauna are scanty although the highly diversified reef Ascidians were collected during undersea faunal ecosystem, mangrove ecosystem and sea-grass surveys in Andaman and Nicobar Islands (Fig. 1) ecosystem provide a favorable condition to grow from August, 2014 to December, 2015 by Self ascidians in Andaman and Nicobar Islands. Ascidians Contained Underwater Breathing Apparatus are well known animals from the era of Aristotle4. A (SCUBA) diving. Craggy Island is a patchy reef area total of about 2900 species of ascidians were recorded with sandy bottom (Fig. 2a & b), Hut Bay Jetty, Little across the world’s ocean while 429 species were Andaman Island is a sandy bottom area with a very recorded from Indian waters till now of which 37 few settlement of hard corals and the pillar of the jetty species are styelid5-19. Andaman and Nicobar Islands is fouled with diverged marine fauna (Fig. 2c & d) represented 8 species of styelid ascidians16. Oka while Trinket Island also represents the similar type reported two ascidians from Andaman and Nicobar of topographical pattern like Craggy Island (Fig. 2e & Islands from the collections of R.I.M.S. Investigator20. f). Collected specimens were defecated and narcotized Styelid ascidians are easily noticeable undersea while with magnesium sulphate and menthol crystals some of the colonial species are observed under the respectively followed by washing in fresh seawater5. rocks. Among the styelids, no non-indigenous species The narcotized specimens were preserved in 4% are reported from Andaman and Nicobar Islands till formaldehyde prepared with seawater. Dissections of now21. The present study reported three species of the specimens were done under Labomed CZM4 styelid ascidians, among them Polycarpa papyra stereo zoom microscope and digitized under Leica Kott, 1985 and Polycarpa argentata (Sluiter, 1890) M205A DFC 500 stereo zoom microscope. 1666 INDIAN J. MAR. SCI., VOL. 47, NO. 08, AUGUST 2018

with inconspicuous muscles (Fig. 3c). Siphons are without armature. About 10 tentacles are found surrounding the branchial aperture. Dorsal tubercle is with slit like opening (Fig. 3d). Dorsal lamina is smooth. There are four branchial folds present per side of the body. Branchial formulae: E 2 (8) 8 (7) 5 (11) 7 (7) 5 DL left Four to six stigmata are found per mesh. Gut loop is narrow and situated in postero-ventral corner of the body in the observed specimen. The long pleated stomach consists of two third of the ascending limb of the gut loop (Fig. 3e). Terminal part of the rectum curves anteriorly toward the opening of atrial aperture. The anal border has 18 narrow and long lobes (Fig. 3f). Endocarps are not enclosed in the gut loop region and they crowded towards the ventral border. On left it is restricted at the anterior part of the gut loop. Gonads are restricted towards the ventral border arranged in almost in row like manner (Fig. 3g & h). Inner part of the body has no gonads only endocarps are present. Body wall has several dots like structures of pigments those are not papillae. Fig. 1 — Study areas of Andaman and Nicobar Islands Distribution: India: Andaman and Nicobar Islands; Identification was made by following literature of Kott1 Elsewhere: Australia1. and Monniot22 using key identification characters. Remarks: Polycarpa biforis (Sluiter, 1904) and Polycarpa contecta (Sluiter, 1904) which has long Results & Discussion stomach and more number of longitudinal vessels in Subphylum TUNICATA Lamarck, 1816 between the branchial folds, are with one endocarp Class ASCIDIACEA Blainville, 1824 enclosed in the gut loop and no endocarps are found Order STOLIDOBRANCHIA Lahille, 1886 on the body wall of the both species1 which Family STYELIDAE Sluiter, 1895 distinguish the Polycarpa papyra from these two species. Also both the species have the S-shaped or Genus Polycarpa Heller, 1877 inverted S-shaped neural gland opening1. Both the 1. Polycarpa papyra Kott, 1985 (Fig. 3) P. biforis and P. contecta not reported from the Indian Material examined: Five individuals were sampled waters till date. The newly reported Polycarpa papyra from Craggy Island of North Andaman has previously been reported only from the Australia1. (13°13.531N; 93°03.394E), 22.viii.2014, depth 5 Further report of this species has not been found till m; Collector: Tamal Mondal (Reg. No.: ZSI/ANRC – the present record. 13613). Morphological features: External appearance: Almost cylindrical body with 2. Polycarpa argentata (Sluiter, 1890) (Fig. 4) thin naked tunic posteriorly and sessile apertures. Material examined: Two individuals were sampled Specimens are about 4.5 cm in length. Apertures are and examined from Hut Bay Jetty, Little Andaman situated distantly from each other (Fig. 3a & b). Some Island (10°35.549N; 92°33.773E), 17.xi.2015, depth epibionts found near the apertures. Test is leathery 6 m; Collector: Jhimli Mondal (Reg. No.: ZSI/ANRC – and brown in colour in in-situ condition (Fig. 3a). 13614). Individuals found in aggregates but no connection is Morphological features: present between individuals (Fig. 3a). External appearance: Body is pear shaped with 4 cm Anatomical characters: Branchial and atrial in length. Branchial aperture is terminal. Atrial aperture apertures are four lobed. Very delicate body wall is is situated at the distance of one third of the body length MONDAL et al.: NEW RECORDS OF THREE STYELID ASCIDIANS 1667

Fig. 2 — a & b: Craggy Island; c & d: Hut Bay Jetty; e & f: Trinket Island. from branchial aperture. Test tough, flexible, slightly border has 20 rounded lobes. There are two endocarps leathery with wrinkles and epibionts. Colour of enclosed in the gut loop and are absent from the body preserved specimen is greyish black (Fig. 4a). wall (Fig. 4d). Gonads are numerous small almost Anatomical characters: Both the apertures have spherical polycarps completely, but not deeply four lobes. Body wall is soft and thin. About 16 embedded in the body wall. They become crowded tentacles are found surrounding the branchial towards ventral midline. Pear shaped male follicles aperture. Dorsal tubercle is simple U shaped (Fig. 4b). are present surrounded the globular ovary (Fig. 4e). There are four branchial folds on each side of the Distribution: India: Andaman and Nicobar Islands; body (Fig. 4c). Dorsal lamina is smooth edged. Elsewhere: Australia, Indonesia1, Palau Island23, Branchial formula: E 2 (8) 3 (10) 4 (10) 4 (10) 4 Gilbert Island, Marshal Island24. DL left Remarks: Polycarpa stirpes Kott, 1985 is with There are about 11-13 stigmata per mesh. Gut loop similar gonads but in P. stirpes the gonads are is short and simple (Fig. 4d). The short stomach has scattered in the body wall not limited to the ventral internal folds but it is not visible from outside. The side1. P. stirpes is not reported from Indian waters. rectum is short and wide. It forms an obtuse angle The species P. argentata may be the native species as with the primary loop after extending forward. Anal its previous distribution indicates an almost pan 1668 INDIAN J. MAR. SCI., VOL. 47, NO. 08, AUGUST 2018

Fig. 3 — Polycarpa papyra Kott, 1985: a: Species in-situ; b: preserved specimen; c: specimen without test; d: dorsal tubercle; e: gut loop; f: anal border; g: gonad arrangements; h: gonads. tropical distribution1,23,24. MONDAL et al.: NEW RECORDS OF THREE STYELID ASCIDIANS 1669

Fig. 4 — Polycarpa argentata (Sluiter, 1890): a: preserved specimen; b: branchial sac with gonad arrangements; c: dorsal tubercle; d: gut loop; e: gonads. Genus: Symplegma Herdman, 1886 Morphological features: 3. Symplegma rubra Monniot, 1972 (Fig. 5) External appearance: A red ring encircles the both Material examined: Part of a colony was sampled siphons (Fig. 5a). Zooids are embedding in the and examined from Trinket Island of Nancowry group oblique manner in the common tunic. Zooids are of islands (07°59.842N; 93°30.569E), 22.xii.2015, attached to the test by only posterior region of their depth 8 m; Collector: Tamal Mondal (Reg. No.: ventral side. Colour of the living zooids are not ZSI/ANRC – 13716). persists in the preservatives (Fig. 5b). 1670 INDIAN J. MAR. SCI., VOL. 47, NO. 08, AUGUST 2018

Fig. 5 — Symplegma rubra Monniot, 1972: a: Species in-situ; b: preserved specimen; c: branchial sac; d: branchial sac showing stigmata; e: gut loop; f: gonads. Anatomical characters: There are 6 long tentacles vessels are present on each side of the body (Fig. 5c and minute tentacles in two orders surrounding the & d). There are 12 rows of stigmata. branchial siphon. Dorsal tubercle has oval opening. Gut forms a loop on the right side of the body Dorsal lamina made up of two smooth membranes. (Fig. 5c). Stomach has 12 plications. There is a long Branchial sac has no folds only four longitudinal and curved pyloric caecum present (Fig. 5e). Gonads MONDAL et al.: NEW RECORDS OF THREE STYELID ASCIDIANS 1671

present on both side of the body (Fig. 5c). Testes are 7 Meenakshi, V.K., Addition to the ascidian fauna of India. J. three lobed (Fig. 5f). Two testis present per body side Mar. Bio. Ass. India, 47(2005) 36-49. 8 Meenakshi, V.K., New Records of five species of colonial with a common opening. No ovary has been found in ascidians of the genus Ecteinascidia Herdman, 1880, from any of the zooids of the colony. the Gulf of Mannar, India. J. Bombay Nat. Hist. Soc., Distribution: India: Andaman and Nicobar 106(2009) 107-112. Islands; Elsewhere: Bermuda22, Zanzibar, 9 Jaffarali, H.A., Sivakumar, V. & Tamilselvi, M. New records Mozambique25, Federated States of Micronesia, of colonial Ascidians from South West Coast off India. 26 Middle-East J. Sci. Res., 5 (2010) 366-373. Palau, Indonesia . 10 Swami, B.S., Udhayakumar, M. & Gaonkar, S.N., Remarks: Symplegma viride stolonica Berril, 1932 Biodiversity in fouling species at Karanja Jetty (Mumbai), is with opaque tunic which forms the continuous west coast of India. J. Mar. Bio. Ass. India, 53(2011) 242-250. passage on the other hand the zooids of S. rubra is 11 Venkataraman, K., Raghunathan, C., Raghuraman, R. & Sreeraj, C.R., Marine Biodiversity in India, Published by separated from each other by small spaces which are 22 Director, Zoological Survey of India, Kolkata. (2012), pp. 1-168. found through its transparent tunic . Symplegma 12 Meenakshi, V.K. & Senthamarai, S., Diversity of Ascidians rubra also has a pan tropical distribution22,25,26 and its from the Gulf of Mannar, pp. 213-229. In: Ecology and presence only in Nicobar group of islands indicates it Conservation of Tropical Marine Faunal Communities, might have brought by the Indian Ocean Currents. edited by K. Venkataraman, C. Sivaperuman C. & Raghunathan, (Springer, Heidelberg) 2013, pp 481. 13 Meenakshi, V.K. & Senthamarai, S., On the Occurrence of Conclusions One new Species and Three New Records of the Genus The studies on reef associated ascidians of Aplidium from Indian waters. J. Chem., Biol. Phys. Sci., Andaman and Nicobar Islands are very limited while 3(2013) 2712-2721. 14 Ananthan, G., Diversity and Ecology of Sedentary Ascidians other works on the Indian ascidians (mainland India) of the Great Nicobar Biosphere Reserve. First Year Progress were made mostly on the artificial structures and Report, (2014), pp. 1-103. inter-tidal habitat. Present study refers the inclusion of 15 Ananthan, G., Stalin, C. & Raghunathan, C., A new record of three species of reef associated ascidians from island ascidians in Indian waters, from the Great Nicobar Biosphere ecosystem of Andaman and Nicobar Islands as new Reserve, Andaman and Nicobar Islands. Mar. Biodiv. Rec., 8 (2015) 1-5. distributional record to Indian waters. 16 Mondal, J., Raghunathan, C. & Mondal, T., Diversity and Distribution of Common Ascidians of Andaman Group of Acknowledgements Islands. Middle-East J. Sci. Res., 23 (2015) 2411-2417. DOI: Authors are grateful to the Director, Zoological 10.5829/idosi.mejsr.2015.23.10.96260 Survey of India, Kolkata for providing necessary 17 Mondal, J. & Raghunathan, C., New record of Two Pyurid facilities and permission to carry out the work. The ascidians of Andaman and Nicobar Islands, India. World J. Zool., 11(2016) 51-54. supports extended by Department of Environment and 18 Jaffarali, H.A. & Tamilselvi, M., Ascidians in Coastal Forests, Andaman and Nicobar Administration during Water: A Comprehensive Inventory of Ascidian Fauna from field trips are duly acknowledged. the Indian coast. Springer, 2016, pp. 155. 19 Mondal, J., Raghunathan, C. 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