New Records on the Opisthobranch Fauna of the Andaman Islands, India

Indian Journal of Geo Marine Sciences Vol. 41(3), June 2012, pp. 215-217

New records on the opisthobranch fauna of the Andaman Islands, India

Dhivya P., V. Sachithanandam & P.M. Mohan* Department of Ocean Studies and Marine Biology, Pondicherry University, Brookshabad Campus, Port Blair – 744 112, Andaman and Nicobar Islands, India *[Email: [email protected]] Received 23 November 2011; revised 30 April 2012

Out of 6000 species of opisthobranch, 164 species belongings to 6 orders and 35 families were reported till date in Andaman and Nicobar Islands. The Haminoea cymbalum (Quoy & Gaimard 1833) had been collected alive in Carbyns Cove, Andaman Islands. This species is the new record in Andaman waters.

[Keywords: Opisthobranch, Haminoea, cymbalum, Island, snail]

Introduction 5% ethanol and the shell was analyzed for the Global distribution of opisthobranch (third large confirmation. Identified specimen was deposited group of snail) is a specialized group of phylum in Zoological Survey of India (ZSI), Regional mollusk1. Marine habitat of opisthobranch is Station of Andaman and Nicobar Islands as a illustrated by two pairs of tentacles and a single gill biodiversity records. located behind the heart. Morphologically diverse group of opisthobranch represents over 6000 species Results and Discussion 2 in all over the world and engage the great variety Phylum – Mollusca 3 of ecological niches . As a defense mechanism it Class – Gastropoda secretes strong acids or toxins and follows the 4,5 Order – Cephalaspidea camouflage characters. Superfamily – Haminoeoidea Rich opisthobranch fauna of the Andaman and Family – Haminoeidae Nicobar Islands has remained largely unstudied Genus – Haminoea because of it geographic remoteness. Out of 164 reported species belonging to 6 orders and 35 families Species – cymbalum (Quoy & Gaimard 1833) 8 in Andaman and Nicobar Islands, 152 species in According to Rudman , the genus Haminoea Andaman Islands and 21 species from Nicobar Islands consists of 70 species and is differentiated by the and nine species are common in both Andaman and characteristics of the shell. The foot is laterally Nicobar group of Islands6. Present study consist a new extended. Functional foot is the development of data and information about opisthobranch species posterior edge of the mantle floor. Wide radula is collected and photographed alive in Carbyns Cove, hook-shaped teeth. Gizzard is large and contains Port Blair, Andaman Islands, along with details on three ridged chitinous plates. their distribution and habitat. The collected species is relatively small and elongate in size (Fig. 2). It is characterized by the Materials and Methods bright orange spots and diffuse purple markings on Rocky shore tide pool environment, biodiversity the translucent greenish body. Shell has a length survey was carried out at Carbyns Cove of 8.5 mm, width is 6.5 mm, strongly inflated, (Lat.11°38’20.25” N; Long. 92°44’54.24” E), Port transparent and without any spiral striae (Fig. 3). Blair, Andaman Islands, India (Fig. 1). During Based on the above morphometry the specimen has this survey (03rd March 2011) opisthobranch was been identified as Haminoea cymbalum (Quoy & collected and identified7. Physical parameters Gaimard 1833). Common name of this genus is were also measured in the study area by Quanta bubble-snails with worldwide distribution across Hydrolab. Collected specimens were preserved with temperate and tropical latitudes. Haminoea cymbalum 216 INDIAN J. MAR. SCI., VOL. 41, NO. 3, JUNE 2012

Fig.1—Study Area

Fig.3—The shell view of Haminoea cymbalum (Quoy &

Gaimard 1833) Fig.2—Haminoea cymbalum (Quoy & Gaimard 1833) are closely shows the morphometry of Haminoea Dictyosphaeria cavernosa in a single tide pool during ovalis but it is easily differentiated by lack of the low tide. Trailing is the peculiar characteristics of purple spots. this species (Fig. 4). Physical parameters such as Based on the review of the opisthobranch in temperature (29°C), salinity (33 PSU), dissolved Andaman and Nicobar waters6, Haminoea cymbalum oxygen (4.2 ml/L) and pH (7.6) were measured in (Quoy & Gaimard 1833) is the first report in the tide pool. This species is also named as Andaman waters. It is found around 50 numbers in cymbal bubble shell. Opisthobranchia of Haminoea the intertidal area at a depth of 0.5 to 2.0 m on cymbalum (Quoy & Gaimard 1833) donated to rocky substrates with an algal environment of Zoological Survey of India (ZSI), Andaman Nicobar DHIVYA et al.: NEW RECORDS ON THE OPISTHOBRANCH FAUNA 217

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