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Home , Duplicaria (gastropod), Hastula, Neogastropoda, Rimella (gastropod), Terebra, Terebra guttata

RECORDS OF AUGER SHELLS (: ) FROM ANDAMAN AND NICOBAR ISLANDS

Introduction are also there (Ganesh, 2004). They make rather The Andaman-Nicobar islands straight trails in the sand as they drag their shells comprising 348 islands of various sizes, run in a either on or just below the surface. Shallow water more or less north-south direction between lat. 6° may be found by divers “trailing” or by 45’ - 13° 45’N and long. 92° 10’ - 94° 15’E. These “fanning” the sand with hands or fins. islands are extremely rich in flora and fauna. Andaman Sea is one of the least investigated In shells of this family the aperture is regions of the Indian Ocean. The physico- small, the outer lip simple, the sturdy columella is chemical and biological property of the Andaman straight or twisted and has strong plaits, and Sea was described by Ansari and Abidi (1989). there is strong to moderate anterior fasciole and Good account on some molluscan resources of notched . There is often a Andaman and Nicobar islands is also available prominent subsutural groove making a change in (Subba Rao, 1980; Tikader and Das, 1985; Tikader the sculpture of the whorls which may be et al., 1986). Information on the distribution of predominantly axial, predominantly spiral or both chiton, strombids and conids came to light axial and spiral producing a cancellate surface. through the works of Rajagopal and Subba Rao Some species are quite smooth and glossy. There (1977), Subba Rao (1970, 1977). is a small, oblong or elliptical operculum.

The neogastropoda are the modern The specimens of have marine snails and include many well-known shells of small to large, narrowly elongate and gastropods such as the cones, conchs, mud attenuate, body whorl small, aperture oblong to snails, olive snails, oyster drill, turnip snails and ovate, surface smooth or with strong spiral auger shells. They have one auricle, one kidney sculpture and often beaded axial riblets (Barry and one monopectinate gill. Family Terebridae Wilson et al., 1994). They are found only in (Adams, 1938) is represented by the auger and tropical warm waters and often move below the pencil shells. Through the present sand leaving well-defined trails. Majority of communication an account of six species of species in this genus lack a although some genus Terebra from Andaman and Nicobar is have radular teeth and a poison sac like those of reported for the first time. . As found here, Terebra most likely encompasses several different groups worthy of Collection of specimens of Terebra was generic or subgeneric differentiation. made from the rocky intertidal zones around various parts of Andaman and Nicobar islands. Systematic account Specimens were collected during the low tide Phyllum : especially spring tide. Most of the specimens Class : were hand picked and brought to the laboratory. Order : Neogastropoda All specimens were preserved in formalin and Family : Terebridae identified subsequently at British Museum based Genus : Terebra on the monograph of Bratcher and Cemohorsky (1987). 1) (Linnaeus, 1758) The shells were collected from North Bay Members of family Terebridae are one of and Aberdeen jetty. They were common on the the most spectacular groups of shelled molluscs coralline sandy beaches of the islands. The shell of sandy shores and coral lagoons in the tropics grows to 160 mm. Totally 19 whorls were found (Bratcher and Cemohosky, 1987). They often arranged in diminishing series upwards. Body move below the sand. They take their vernacular whorl consisted of three spiral bands of dark names from their long, slender and pointed shells, brown rectangular spots. Other whorls consisted which are often brightly coloured and delicately of two spiral band. Shell was whitish/pale in colour sculptured. Terebrids of Andaman live in clean with minute, oblique transpirals and fine spiral sand on coral reef, as well as in the surf zone of ridges. beaches. Some deeper water species of terebrids

Seshaiyana Vol.14 No.1 (2006) 6 Measurements: Length – 95 mm; Width of body whorl - 15 mm Distribution: Indo-West Pacific.

Terebra crenulata (Linnaeus)

4) Terebra dimidiata (Linnaeus, 1758) The shells were collected from Ross Terebra subulata (Linnaeus) island and little Andaman. Not common in occurrence. Number of whorls ranged from 30 to 32. The shell has distinctive orange-red colour 2) Terebra hectica (Linnaeus, 1758) with irregular, elongated white spots or markings Specimens were collected from the on them. It can grow from 30 to 130 mm in length. Aberdeen jetty and Wandoor Marine Park. The Base sloppy, aperture elongate-quadrate and shell was moderately thick with straight sides and collumella straight. Spire with one broad and one sharp apex. Whorls were smooth or occasionally narrow. Whorls were arranged alternately with with growth striae. Thickened with a callus at deep suture. The shells were found distributed suture. Creamy with purplish brown and broad mainly in the mid and low tide surf zone. spiral bars. Sometimes unicolorous white. They Measurements: Length – 75 mm; Width of body were common on rocky shores. whorl – 18 mm Measurements: Length – 65 mm; Width of body Distribution: Indo-West Pacific. whorl – 9 mm. Distribtuion: Indo-West Pacific.

Terebra dimidiata (Linnaeus)

Terebra hectica (Linnaeus) 5) (Roeding, 1798) Shell was collected from Aberdeen and was found occupied by a hermit crab. This 3) Terebra crenulata (Linnaeus, 1758) species was represented by a single individual in These shells were collected from Rangat the collections. This species is rare in this island. Bay and Aberdeen. Not common in occurrence. The shell consisted of 18 whorls and part of each The shell was thick. It can grow up to 120 mm in whorl just below the suture was slightly raised as length. The specimen consisted of 15 whorls a spiral ridge. Each spiral consisted of spots with with a spiral row of blunt, slightly elevated white and brown spots alternately. It also tubercles just below the suture. There were consisted of fine and wavy transpiral lines transpiral brown lines in the groove in between through out the shell. tubercles. They are described as oatmeal in Measurements: Length – 64 mm; Width of body colour. It carried spiral row of red-brown dots whorl – 15 mm. along the entire body whorl’ two on the spiral Distribution: Indo-West Pacific. whorls and three on the body whorl. The whorls were flat sided, turreted, base sloping and aperture ovate. Many shells were collected from the intertidal coralline sand. Measurements: Length – 90 mm; Body whorl width – 18 mm. Distribution: Indo-West Pacific. Terebra guttata (Roeding)

7 Seshaiyana Vol.14 No.1 (2006) 6) Terebra maculata (Linnaeus, 1758) gastropods Part III (Neogastropods). Specimens were mostly collected from Odyssey Publishing Co., Australia, 218-229. Aberdeen jetty (Port Blair) and Laxman beach (Great Nicobar). This species was found to be Bratcher, T. and W.O. Cemohosky, 1987. Living common in the islands on the sandy beaches. Terebridae of the world. American Number of whorls ranged from 20 to 22. Mouth Malacologist Inc. Florida, 240 pp. was wide anteriorly and body whorl slightly inflated. Two spiral bands on each whorl of dark Ganesh, T., 2004. Macrobenthic communities of brown with rectangular spots just below the the northeast Indian Shelf, Bay of Bengal. suture were found. Spots were bigger in upper Ph.D. Thesis, Andhra University, Waltair, 205 band. This is the largest among the species of pp. Terebra having the capacity to grow up to 250 mm in length. Shells were white in colour with Rajagopal, A.S. and N.V. Subba Rao, 1974. purple-brown blotches on each whorl. Onchiton from the Andaman and Nicobar Measurements: Length – 82 mm; Width of the islands. J. mar. biol. Ass. India, 16: 398-411. body whorl – 25 mm Distribution: Indo-West Pacific. Subba Rao, N.V., 1970. On the collection of Strombidae (Mollusca : Gastropoda) from Bay of Bengal, Arabian sea and Western Indian Ocean with some new records 1. Genus Strombus. J. mar. biol. Ass. India, 12(1&2): 109-124.

Subba Rao, N.V., 1977. On the collection of Strombidae (Mollusca : Gastropoda) from Bay of Bengal, Arabian sea and Western Terebra maculata (Linnaeus) Indian Ocean with some new records 1. Genus Lambis, Terebellum, Tibia and The polymorphic family Terebridae is Rimella. J. mar. biol. Ass. India, 19: 21-34. widely distributed in Indo-Pacific region. There are however, geographical differences among the Subba Rao, N.V., 1980. On the of morphological features in different species. The Andaman and Nicobar islands. Records of of the family Terebridae remains Zool. Surv. of India, 77: 39-50. unsatisfactory, due to the fact that it is mainly based on characters of the shell. Currently four Tikader, B.K. and A.K. Das, 1985. Glimpses of genera namely , Hastula, Terenolla life of Andaman and Nicobar islands. and Terebra are recognized. All the six species of Spl. Pub. Zool. Surv. of India, Calcutta, 1- genus Terebra described here have distinct shell 170. features. However these should be strengthened with other features. Tikader, B.K., A. Daniel and N.V. Subba Rao, 1986. Sea shore of Andaman and References Nicobar islands. Zool. Surv. of India, Adams, W., 1938. Sur quelques Cephalopods des Calcutta, 1-188. isles Andamans. Bull. Nat. Hist. Nat., Belg., 14(7): 1-25. Z.A. Ansari*, S.A.H. Abidi and C.K. Haridevi** Ansari, Z.A. and S.A.H. Abidi, 1989. Andaman National Institute of Oceanography sea – its physical, chemical and biological Dona Paula, Goa – 403 004 characteristics. Manag. Aqua. Ecosyst., 21- **ASRB, Krishi Anusandhan Bhavan 32. Pusa, New Delhi *E-mail: [email protected] Barry Wilson, Carina Wilson and Patrick Baker, 1994. Australian Marine Shell: Prosobranch

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