World Journal of Zoology 6 (4): 331-333, 2011 ISSN 1817-3098 © IDOSI Publications, 2011 New Distribution of Siratus Virgineus ponderosus (Sowerby, 1879) Family Muricidae, in Mandapam Coast, India C. Stella, M. Kalaiarasi and C. Balalakshmi Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi Campus, Thondi-623409, Tamil Nadu, India Abstract: The present study reported the occurrence of Siratus virgineus ponderosus in the Mandapam coast, south east coast of India as a first hand record based on the shell collected from the intertidal area and fish landing center. Identification is mainly based on the external morphology of the shell. The present paper described the taxonomic status and description of the shell morphology of the species collected from Mandapam coast. This species Siratus virgineus ponderosus is included in the Genus Siratus and the family Muricidae. Key words: Gastropoda Chicoreus virgineus Taxonomic status Description Shell morphology INTRODUCTION The family Muricidae contains more than 300 species that inhabit tropical and the temperate waters. There are essentially shallow water dwellers ranging from the tidal zone to depths of 50 fathoms or more and live in a variety of biotopes, varying from rocky tidal pools to sandy bottom areas and mud flats. Investigation of the Muricidae revealed the existence of some species that are already known to occur in the geographical area of south east coast of India. The tropical members of the family Muricidae vary in their morphological features to a great extent from those of the subtropical or temperate forms. Fig. 1: Showing the Mandapam coast The family Muricidae has been subjected to intensive study by Taylor and William [1], Freeman and Silva [2], external shell morphology, this species Siratus virgineus Spright [3], Svend [4] and Svend and Nipavan [5]. The ponderosus differs from Chicoreus virgineus as it has information of south Indian Muricids are limited. axial ribs, strong varix, heavy node, deep narrow space, In May 2009, during the course of the coastal survey shape of ‘aperture’, thickness, size, edge of the outer lip, along the Mandapam coast of south east coast of India spine and spiral sculpture. Based on the earlier records, (Fig.1), shells were collected manually from the intertidal collection of samples deposited in the zoological survey area and fish landing centers of Mandapam and the of India -chennai and the external morphology of the shell specimens were transferred to the laboratory for of this species Siratus virgineus ponderosus,, reported identification. The identification was mainly based on the for the first time in Mandapam coast external morphology of the shells. The specimens were stored in 10%formalin and the colour of the shells was Systematics: recorded. The species of Muricidae family has close Family : Muricidae resemblance to Chicoreus virgineus but it has some Genus : Siratus apparent differences in the shell sculpture. Based on the Species : virgineus ponderosus [Sowerby,1879] Corresponding Author: C. Stella, Department of Oceanography and Coastal Area Studies, Alagappa University, Thondi Campus, Thondi-623409, Tamil Nadu, India. 331 World J. Zool., 6 (4): 331-333, 2011 The operculum is small, thick, calcareous and pauscipiral, brown and white in colour. The length of the operculum is 15mm and the width is 10 mm in an animal with a shell length of 6.7 cm. Remarks: Siratus virgineus ponderosus, is close resemble to Chicoreus virgineus [Roading 1798], Muricanthus virgineus and Muricanthus kuesterianus [Tapparone-Canefri, 1875] but it differs in having axial ribs, weak varice, deep narrow space, shape of the aperture and edge of the outer lip. DISCUSSION PC-Protoconch TC-Teleoconch BVV-Body whorl The shell morphology of the present species is OL-Outer lip A-Aperture V-Varice distinctly differ in their, sculpture, thickness and size from SC-Siphonaicanal the close resembled species of Chicoreus virgineus [Roading 1798], Muricanthus virgineus and Fig. 2: Species of siratus virgineus ponderosus Muricanthus kuesterianus [Tapparone-Canefri, 1875]. According to Kitching et al [6]. The shell weight is Type species by Original designation: Chicoreus influenced by shape as well as the thickness. The difference in shell thickness may be attributed to the virgineus [Roading 1798] variation in their environmental niche and the availability Locality : Mandapam fish landing centre of food. There is also an apparent difference in the Distribution : Mandapam coast and Gulf of Mannar relationship between shell size and aperture size. The population may be attributed to differential feeding rates. Description The present study is also in conformity with the statement Siratus Virgineus Ponderosus: The shell of Siratus of Kitching and Lockwood [7]. Remarkable variations virgineus ponderosus, show similar pattern throughout between the species reside in the varices and teeth. A the study with little variations (Fig. 2). The following strong thick varix is formed at the edge of the outer lip of description is mainly based on non eroded shells of the body whorls at regular intervals. Each varix represents younger specimen, where the shell sculpture could be a resting period in the growth of the shell. The seen clearly. The shell of Siratus virgineus ponderosus,is intervarices of the shell represent active periods of the heavy and globose shape. Spire moderately low with shell deposition. However, the duration of shell simple suture. The shell up to 6.5 cm in length with 2 deposition or the time taken for the shell growth was not protoconch whorls and up to 4 teleoconch whorls. noticed. The present observation is in conformity with the Protoconch whorls are rounded with smooth axial ribs. observation of Carriker [8] on Murex brevifrons and First and second teleoconch whorls consist of 7 to 9 axial Mured fulvescens. Spight and Lysons [9] had enough ribs. Third and fourth whorls form varices. The last documents about shell deposition of resting period by the teleoconch body whorls have 3 varices without spine. muricids. Each successive varix has a more elaborate Each varix of last body whorl has posteriorly 2 closed teeth. The earliest teeth are flat and have sword like spines. Intervaricial axial sculpture consists of a single structure. The spines and varices may be resorted by heavy node generally closer to the growing edge of the Fretter and Graham [10]. Snails used their labial teeth on shell. Spiral sculpture consists of major cords, minor cords several occasions during feeding. Teeth have been used and spiral threads. There is a strong varice present on as wedges to open shell of prey [11]. outer surface of the outer lip. Inside the outer lip, no deep notch is present. Outer lip is strong denticulate without REFERENCES labral tooth. Aperture fairly oval and small. Colour of the aperture is pink. Siphonal canal bears 2 short ventrally 1. Taylor, J.D. and J.K. William, 1969. The shell structure closed spines. Columellar lip is smooth. Shell colour is and mineralogy of Chema pellucid Broderlip. dull white with brown bands. The Veliger, 11: 391-398. 332 World J. Zool., 6 (4): 331-333, 2011 2. Freeman, S.E. and S.R. Silva, 1973. SEM Studies on the 7. Kitching, J.A. and J. Lockwood, 1974. Observations radule of two marine gastropods. Micron, 4: 247-255. on shell form and its ecological significance in Thaisid 3. Spright, T.M., 1973. 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