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International Journal of Zoology and Research (IJZR) ISSN 2278-8816 Vol. 3, Issue 4, Oct 2013, 23-30 © TJPRC Pvt. Ltd.

THE ONCHIDIUM (GASTROPODA: PULMONATA: ONCHIDIIDAE: GENUS: ONCHIDIUM) OF THE URAN, WEST COAST OF INDIA PRADNYA PATIL & B. G. KULKARNI Department of Zoology, Institute of Science, Mumbai, Maharashtra, India

ABSTRACT In India, Maharashtra state has a coastline of 720 km having all types of shores. Most of the available Reports are on macrobenthos diversity on coast of Maharashtra. It is mainly focused on diversity of mollusc like gastropod and pelecypoda. However, meagre data is available on diversity of Pulmonata gastropod on coast of Maharashtra. Due to such encroachment and reclamation, a species displacement has been reported on coast of Konkan. In recent years urbanization and industrialization in coastal belt of Konkan has resulted into modifications of topography of these areas. Present work on assessing diversity of Onchidium species on coast of Uran has been recorded three species of Onchidium. O. verruculatum, O. peronii, Platevindex species. The present investigation is the first report on diversity of Onchidium species on the coast of Uran.

KEYWORDS: Diversity, O. verruculatum, O. peronii, Platevindex species INTRODUCTION Census of Marine Life (www.coml.org) programme proved that oceans have great diversity of life. 33 out of 34 major phyla are represented in the ocean, whereas only 15 phyla’s are presented on the land. Census of Marine Life also proved that every niche in marine ecosystem is occupied by the life. Although every oceanic country has participated in an international project of Census of Marine Life, a little attention has been paid on coast of India to measure the diversity of marine life. The Census of Marine Life established a baseline of marine life diversity, distribution, and abundance against which future change can be measured. Census of Marine Life aggregated more than 30 million of species; including 1,200 newly discovered and described species. Another 5,000 or more await formal description. Census of Marine Life created the Ocean Biogeographic Information System, the world’s largest online repository of geo-referenced data that nations can use to develop national and regional assessments and to meet their obligations to the Convention on Biological Diversity and other international commitments. Census of Marine Life collaborated with the Encyclopaedia of Life to complete ~ 90,000 marine species pages and provided and continues to serve as the marine component of the Global Biodiversity Information Facility. Census of Marine Life supported the World Register of Marine Species, which confirmed that excluding microbes approximately 250,000 valid marine species have been formally described in the scientific literature, with an estimated at least 750,000 more species remaining to be described. NaGISA (http://nagisa.cbm.usb.ve) the program for assessing diversity of near shore has executed many projects to assess diversity of intertidal zones. Reports of near shore diversity are available on webpage of NaGISA. Maharashtra has a coastline of 720 km having all types of shores. Reports are available on macrobenthos diversity on coast of Maharashtra. Among these reports of Parulekar et.al (1976), Parulekar (1981) Ingole et. al. (2002, 2009), Chhapgar (1958) Zingde (1999) Jaiswar and Kulkarni (2000), Shahnawaz et.al. (2006), Jaiswar et.al. (2007), Datta et.al. (2010), Balli et.al. (2011) are worth to mention here. Most of the available reports pertains to diversity of macrobenthos on coast of Maharashtra mainly focus on diversity of mollusc like gastropod and pelecypoda. However, meagre data is available on


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Pradnya Patil & B. G. Kulkarni

diversity of Pulmonata gastropod on coast of Maharashtra. (Awati and karandikar, 1948; Gopinadha et.al., 1980; Datta et.al., 2008). In recent years urbanization and industrialization in coastal belt of Konkan has resulted into modifications of topography of these areas. Due to such encroachment and reclamation a species displacement has been reported on coast of Konkan. (Khade and Mane 2012a,2012b,2012c).Therefore, present work on assessing diversity of Onchidium species on coast of Uran has been undertaken, to create a data base with respect to present circumstances of human settlement on coast of Uran.

MATERIAL AND METHODS The selected sites were visited during low tide for collection of the Onchidium species. The animals collected manually from respective sites were washed with sea water and brought to the laboratory for taxonomical studies. The morphological characters of Onchidium are extremely variable within the populations, and therefore the diagnoses and identification keys are based on type specimens when available. The identification of Onchidium species was done as per reports of Fretter (1943); Awati and Karandikar (1948) and Dayrat (2009). The dorsal eyes morphology is used by many authors to distinguish between species. Table 1 shows the mainly characters used in the keys. Species Diversity Topography of Selected Sites A Preliminary survey of Uran coast was carried out to locate niche of Onchidium species. It has been noticed that usually marshy areas in mangrove zones are habituated by Onchidium species. Furthermore, population of Onchidium species was also recorded at rocky shore covered with mud near, marshy areas of mangroves. After thorough survey of Uran coast Site-I named as Pirwadi beach and Site - II called as Dookar khadi were selected for collection of Onchidium species Site-I Uran Pirwadi Geographically, Uran city (Latitude 180 50’ 20” N and Longitude 720 57’ 5” E) is located on the coast of Arabian Sea along the eastern shore of Mumbai harbour opposite to Colaba. Total length of Uran coast is approximately 16 km and it is marked by rocky, muddy and sandy substratum. Most of the coast is rocky towards the sea side and Marshy towards upper middle zone. Pirwadi site located 7 km away from Uran city. The moderate cover of mangrove exists at Pirwadi Site. Site II: Uran Dookar khadi Dookar creek of Uran city opens on one side into the sea near Bori is located at (Latitude: 18° 48' 20" N Longitude: 72° 59' 33" E). A dense cover of mangrove trees (Avicennia marina) is present in most of the creek. Presence of loamy mud substratum is one of the favourable factors for habitat of Onchidium species in this creek. Since the creek is in proximity of Uran city, it is used as dumping ground and therefore heaps of garbage is frequently seen on shore of the creek. During present survey three species of Onchidium were collected from both the sites during low tide. Among the three species Onchidium verruculatum was abundantly found at Site I where most of the area is marshy and of loamy substratum. During collection the animals were observed to creep on the substratum exposed to the atmosphere. Creeping trail of O. verruculatum was followed to locate the species. At the time of high tide it was observed that animals were hiding themselves in crevices of the rocks present on the shore. However, two animals of O. verruculatum found to follow each other in a straight line during copulation. Further, more than two animals were found in group showing courtship behaviour Juveniles of O. verruculatum found to hide in burrows of the fiddler crab. Although Onchidium peronii was


The Onchidium (Gastropoda: Pulmonata: Onchidiidae: Genus: Onchidium) of the Uran, West Coast of India

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available at both the Sites, the percentage of availability of O. peronii was maximum at Site II where mangroves (Avicennia marina) are abundant. It was observed that O. peronii camouflage with the substratum present near the mangroves. A group consist of 7-8 O. peronii was observed near the mangroves. The density of O. peronii was recorded right from upper part of intertidal zone to the lower part of intertidal zone. Platevindex species was collected from both the sites. However, at site I higher density of Platevindex species was observed than that at Site II. Platevindex species was also observed to live in a group of 5-6 animals. Since dorsal eyes are absent in Platevindex species it is not prominently seen against the background of substratum. Therefore, this species is to be collected after careful observation. It has been noticed that during dusk time Platevindex species density was higher at Site I.

RESULTS Three species of Onchidium mainly collected from different sites were brought to the laboratory for morphological studies. Onchidium species were maintained under laboratory conditions in aquaria with sufficient sea water (25cm×25cmX25cm). External morphological characters were observed in fresh as well as in preserved specimens. The basic plan of morphological characters is found to be uniform in all three species of Onchidium. However, variations in certain morphological characters were noticed in all three species of Onchidium. The basic plan of morphology includes presence of mantle on the dorsal surface. The mantle is thickly covered with tubercles or body warts. These tubercles are in wide variety of form, size and structure ranging from minute granules to large protuberances scattered all over the dorsal surface. It has been noticed that tubercles located at posterior side of the mantle are irregularly branched and have in general a bushy appearance which are commonly known as ‘Gill trees’. Whereas, unbranched types of tubercles are flattened at their free end on which the mantle eyes are situated. Therefore, these tubercles are also called as ‘ocular papillae’. These mantle eyes either located singly or in groups consisting of two or more on each ocular tubercle. The largest ocular group observed to contain six eye spots. However, three to four eye groups were commonly observed. The fleshy elongated foot present on the ventral side of the body. The foot is surrounded by all the sides by peripheral extension of the mantle known as hyponotum. The hyponotum is distinguished as per its location into the right, left, front, and the hind hyponotum regions. The mouth is situated ventrally at anterior end of body between foot and front hyponotum. The mouth is surrounded laterally by fleshy lobes called as labial palp which are also known as oral lappets or oral lobes. A pair of conical retractile tentacles carrying cephalic eyes at the tips is present in the antero-lateral corners of the labial palp. The male genital opening of the slug is located on right side between tentacle and labial palp. Between the foot and hyponotum three apertures are situated at the hind end of ventral side of the body. Out of these three, one aperture called as anus is placed in the median line and the female genital aperture lies right of the anal opening continuous to peripodial groove, the third aperture which is as large slit is located posterior to the anus and it leads the pulmonary chamber of the slug. Colour: In live condition general body colour is brown to that of mud colour where animal lives. The ventral surface is light yellowish grey, whereas foot sole is more yellowish. Skin: Skin of Onchidium species is generally thick muscular with dorsal tubercles scattered all over of it as mentioned in morphology characteristics. When skin layer was observed under the compound microscope it shows presence of various types of pores In Onchidium verruculatum two types of pores are seen. A pore through which dorsal eye protrude is wide with conical opening, whereas other pores are long and cylinder with the triangular opening. Similar types of pores are also seen on the skin of Onchidium peronii. However, these pores are oval in shapes and other pores


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Pradnya Patil & B. G. Kulkarni

have narrow opening. In Platevindex species all over the skin dark black circular shaped spots are present with narrow openings. Internal Anatomy: When species of Onchidium dissected out to observe the body organ arrangement, it shows that viscera are located in specious body cavity. The reproductive organs consisting male and female genital organs are also seen in the body cavity.

CONCLUSIONS Position of various organs in three species of Onchidium is given in (Table 2) Radula: One of the distinctive features of Onchidium species is presence of radula in the buccal mass as of other gastropods After dissecting out the radula it is clearly noticed that the radula varies with respect to structure, size and shape in all three species of Onchidium. In case of Onchidium verruculatum center of radula is pointed, anterior sides are semicircular and posterior sides are curved. In case of Onchidium peronii centre of radula is pointed, anterior sides are slanting downwards and posterior sides are conical. In Platevindex species radula is acutely pointed, anterior side are markedly slope downward and posterior sides are cuboidal. The radular teeth of O. verruculatum are large than that of O. peronii and Platevindex species. In O. verruculatum distinct central rachis of radula is observed whereas in case of O. peronii and Platevindex species central rachis is not visible. The arrangement of radular teeth is compact in case of O. peronii Onchidiids have a worldwide distribution, with the exception of the Arctic and Antarctic (Hoffmann 1928, 1929). Most species are marine and live in the upper intertidal zone, either in rocky, sandy, or muddy habitats, including mangroves. However, two species live in brackish habitats and tolerate fresh water: Onchidium typhae (Buchannan, 1800), and Labella ajuthiae (LabbÊ, 1935). Three terrestrial species have also been described from high-elevation rainforests: Semperella montana (Plate, 1893), from Sibugan Island, Philippines; Platevindex ponsonbyi (Collinge, 1901), from Borneo; and Platevindex apoikistes (Tillier, 1983), from Mindoro, Philippines. Although Onchidium species are reported widely, Onchidiidae is a poorly known taxon in many regards. Systematics of Onchidiidae has been revised by many investigators. Anatomical studies of Onchidiids are also not reported adequately. Most of the literature on Onchidiids was published before 1940’s. Few studies have been published since then (e.g Fretter 1943, Awati and karandikar 1948, Marcus 1978, 1979, Tiller 1983, Britton 1984, Hyman 1990, Weiss Wagele 1998, Dayrat 2009) who have reviewed systematics of Onchididiiae with a checklist of nominal species. A checklist of all 143 species names available in Onchididiiae is a first step towards systematic revision. As per this checklist and revision on Onchididiiae species, three species as Onchidium verruculatum, Onchidium peronii and Platevindex species are reported. World Register of Marine Species has described 143 species of Onchidium. Which includes Onchidium verruculatum, Onchidium peronii and Platevindex species. Among the three species recorded at Uran coast Platevindex species had been reported as Oncis plate (Baker 1938). Further, according the WoRMS, Platevindex species is given as revised nomenclature for Onchidium martensi and Oncis Plate. Onchidium peronii Cuvier (1804) has also been given by WoRMS (2010). Five synonyms are reported for Onchidium peronii as per catalogue of life and Peronia peronii is given as accepted name. However, as per the catalogue of WoRMS (2010) Onchidium peronii has been given as correct nomenclature. Therefore, during present investigation Onchidium peronii has been accepted nomenclature. However, in literature on Onchidium species published recently nomenclature like Onchidium verruculatum is widely used. Therefore, during present investigation same nomenclature has been given after studying thorough morphological characters and comparison to data with available literature of Onchidium species. Similarly by studying morphological characters of all


27

The Onchidium (Gastropoda: Pulmonata: Onchidiidae: Genus: Onchidium) of the Uran, West Coast of India

the three species of Onchidium and comparing with available literature the identification of three species namely Onchidium verruculatum, Onchidium peronii and Platevindex species is confirmed. Diversity of Onchidium species on coast of oceanic countries has been well documented (Kenny and Smith, 1987; Wu Xu -Feng et.al., 2010; WU Wen-Jian, 2010; Josephine, 2007; Tiller, 1983; Dayrat et.al., 2010a; 2010b; 2011). However, barring few reports sufficient data is not available on distribution of Onchidium species from West and East coast of India. (Naik et.al., 1990; Dey, 2006; Saravanakumar et.al. 2007; Mitra, 2008) and only few authors have reported presence of Onchidium species on coast of Maharashtra (Awati and Karandikar 1948). Awati and karandikar (1948) has reported three species of Onchidium which include Onchidium verruculatum, Onchidium simorthi, and Onchidium martensi in several areas of island shore in and around Bombay.Of these O. verruculatum was found to inhabit rocky places along the shore in nook and corners and under stone areas absolutely devoid of any species of so called mud skippers. The other two species were invariably found in muddy places which were also rich in mud skipper population. In present investigation also three species of Onchidium are collected from rocky and muddy shore of Uran coast. The present investigation is the first report on diversity of Onchidium species on the coast of Uran. Table 1: Comparison of Morphological Characters in Onchidium species of Uran Coast (West Coast of India) Sr. No. 1.

Characters Size

Onchidium verruculatum ≤ 70 mm Oval and slightly dorsoventrally flattened. Brown 6-7 black spot located on each dorsal eye which are circularly arranged. Short and conical. Fully retractable into the head. Lobes of labial palp are broad &. sensory lappets present on each lobe

Onchidium peronii ≤ 20 mm Oval and elongated

Platevindex species ≤ 40 mm Oval with circular dorsal hyponotum Dark Black

2.

Shape

3.

Colour

4.

Dorsal eyes

5.

Tentacular eyes

6.

Labial palp

7.

Pulmonary aperture

Wide pulmonary aperture extendible up to 5 mm.

Pulmonary aperture extendible less than 1 mm.

8.

Pedal sole/ foot

Muscular large foot smaller than hyponotum.

Muscular fleshy foot broader than hyponotum.

9.

Ventral side

Yellowish grey

Greenish with mottled yellow margin.

white

10.

Creeping behaviour

Creeping marks distinctly seen.

No creeping mark seen

No creeping mark seen

Drab grey 4-5 black spot located on each dorsal eye which are unevenly located on the entire body. Short and conical. Fully retractable into the head. Lobes of labial palp are fused and small.

Dorsal eyes are absent. Long and slender. Fully retractable into the head. Notch present in between lobes of labial palp. Prominent but small pulmonary aperture extendible up to 3 mm. Narrow slender foot smaller than hyponotum.

Table 2: Observations on Visceral Organ of Onchidium species Sr. No. 1. 2. 3.

Visceral Organ Colour of Hepatopancreas Heart Colour of albumen gland

Onchidium verruculatum Dark brown Lies under the albumen gland White

Onchidium peronii Light yellowish brown Not easily seen Pinkish

Platevindex species Light brown Clearly observed Yellowish

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Awati P.R. and Karandikar K.R. (1948) Onchidium verruculatum (Anatomy, Embryology and Bionomics). Zoological Memories, University of Bombay. 1–53

2.

Baker H.B. (1938) Nomenclature of Onchidiidae. The Nautilus. 51:85–88


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3.

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10. Dayrat B. (2009) Review of the current knowledge of the systematics of Onchidiidae (Mollusca: Gastropoda: Pulmonata) with a checklist of nominal species. Zootaxa 2068: 1–26 11. Dayrat B. (2010a) Anatomical re-description of the terrestrial Onchidiid slug Semperoncis montana (Plat E, 1893). Malacologia. 52(1): 1−20 12. Dayrat B. (2010b) Comparative anatomy and taxonomy of Onchidium vaigiense (Gastropoda: Pulmonata: Onchidiidae) .Molluscan Research. 30(2): 87–101 13. Dayrat B., Conrad M., Balayan S., White T.R., Albrecht C., Golding R., Gomes. S. R., Harasewych M.G., Martins A. (2011) Phylogenetic Relationships and Evolution of Pulmonate Gastropods (Mollusca): Newin sights from increased taxon Sampling. Molecular Phylogenetics and Evolution. 14. Dayrat B., Zimmermann S. and Raposa M. (2011) Taxonomic Revision of the Onchididiiae (Mollusca: Gastropoda: Pulmonata) From the Tropical Eastern Pacific Journal of Natural History 45(15-16):939-1003 15. Dey A. (2006) Handbook on mangrove associate molluscs of Sundarbans. Zoological Survey of India, Kolkata:96 16. Fretter, V. (1943) Studies in the Functional Morphology and Embryology of Onchidella celtica (Forbesand Hanley) and their Bearing on Its Relationships. Journal of the Marine Biological Association, United Kingdom. 25:685–720 17. Gopinadha C. S., Pillai and Appukuttan K. K. (1980) Distribution of Molluscs in and Around the Coral Reefs of the South-eastern Coast in India Journal of Bombay Natural History Society 77:27-4 18. Ingole BS, Rodrigues N, Ansari ZA, (2002). Macrobenthic communities of the coastal waters of Dabhol, west coast of India. Indian J. Mar. Sci., 31(2): 93-99 19. Ingole BS, Sivadas S, Nanajkar M, Sautya S, Nag A (2009). A comparative study of macrobenthic community from harbours along the central west coast of India. Environ. Moni. Asses., 154, 135–146.


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20. Jaiswar A. K. & Kulkarni, B. G. (2000). Neritidae of Mumbai (Bombay) coastline, west coast of India. Indian Journal of Marine Sciences. 29, 258-262. 21. Jaiswar A. K., Kulkarni B. G. and Chakraborty S. K. (2007) Diversity indices, distribution pattern and biomass as indicator of health status of aquatic ecosystem. Journal of ecophysiology and occupational health. 7:25-37. 22. Josephine K.Y. (2007) A Brief account and revision on gastropods found in local mangroves Hong Kong Biodiversity Agriculture, Fisheries and Conservation 14 23. Kenny R. and Smith A. (1987) Distribution of Onchidium Damelii Semper (Gastropoda , Onchldiidae) Pacific Science 41:1-4 24. Khade S.N. and Mane U.H. (2012a) Diversity of Bivalve and Gastropod, Molluscs of some localities from Raigad district, Maharashtra, west coast of India. Recent Research in Science and Technology, 4(10): 43-48 25. Khade S.N. and Mane U.H. (2012b) Diversity of Bivalve and gastropod Molluscs from selected localities of Raigad district, Maharashtra, West coast of India World Journal of Science and Technology, 2(6):35-41 26. Khade S.N. and Mane U.H. (2012c) Diversity of Onchidium species of Raigad district, Maharashtra, West coast of India Recent Research in Science and Technology 4(10):16-20 27. Labbé, A. (1935) Sur une forme nouvelle de Silicoderme, Elophilus ajuthiae nov. Gen. nov. sp. Bulletin de la Société Zoologique de France, 60, 312–317. 28. Marcus, Ev. (1978) The Western Atlantic Species of Onchidella (Pulmonata). Sarsia 63:221–224 29. Marcus, Ev. (1979) The Atlantic species of Onchidella (Gastropoda Pulmonata) part 2. Boletim de Zoologia, São Paulo, 4, 1–38. 30. Naik C. G. Kamat S. Y. Parameshwaran P. S. Das B. Patel J. Ramani P. Bhakuni D. S., Goel A. K. Jain S. and Srimal R. C (1990) Bioactivity of Marine Organisms Part V : Screening of Some Marine Fauna From the Indian Coast Mahasagar 23(2):153-157 31. Parulekar, A. H., (1981) Benthos of the Arabian Sea Journal of the Indian Fisheries Association. 6, 1-10. 32. Parulekar, A. H., Nair, S. A., Harkantra, S. N., Ansari, Z. A., (1976) Some quantitative studies on the benthos off Bombay. Mahasagar, 9 (1 &2), 51-56. 33. Shahnawaz Ali, Purushothaman C. S. and Jaiswar A. K. (2006) A preliminary study on richness, diversity and evenness of decapod crustaceans off Mumbai coast. Journal of the Marine Biological Association of India, 47 (2): 205-207. 34. Tillier S. (1983) A New Mountain Platevindex From Philippine Islands (Pulmonata: Onchidiidae). Journal of Molluscan Studies. 12a:198–202 35. Weiss, K. & Wägele, H. (1998) On the Morphology, Anatomy and Histology of Three Species of Onchidella (Gastropoda:Gymnomorpha: Onchidiida). Archiv Für Molluskenkunde. 127:69–91 36. Wu Wen-Jian, Shen Bin, Chen Cheng, Shen He-Ding*, Wei Luan-Luan, Wang Ling, Li Kai (2010) Preliminary classification and phylogenetic relationship among Onchidiidae in China inferred from 18s RNA partial sequence. Zoological Research 31(4): 381−386


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