GURUMAYUM and KOSYGIN : On a collection of some from Cauvery estuary, Tamil Nadu 131 ISSN 0375-1511

Rec. zool. Surv. : 115(Part-2) : 131-140, 2015

ON A COLLECTION OF SOME MOLLUSCA FROM CAUVERY ESTUARY, TAMIL NADU

SD Gurumayum* and L Kosygin** Estuarine Biology Regional Centre, Zoological Survey of India Hilltop, Gopalpur-on-Sea, Ganjam, Odisha 761002 Email : [email protected]

INTRODUCTION Gastropods and Bivalves constitute 98% of the total population of mollusca and they inhabit land, The Cauvery river is India’s fourth largest river, draining about 89,600 sq. km (Jayaram et al., freshwater and marine environment and play a 1982). The river originates at Talakaveri, Kodagu crucial role in maintaining the integrity of various district of Karnataka and flows generally south ecosystems. Certain of mollusca are of east and finally emptying into the Bay of Bengal. direct or indirect commercial and even medical Since historical times the river is extensively importance to humans. They have been, important utilized for agriculture, fisheries, irrigation and to humans throughout history as a source of food, navigation purposes. In recent years they have jewelry, tools, decorations, currency, musical been further subjected to many multi-purpose instruments and they inhabit land, freshwater and hydro-electric and other projects. As a result, a marine environments and play a and more. Hornell number of old and new barrages, weirs, anicuts or (1921) listed the common mollusks of south India dams, have been constructed across the river. It is and consequently numerous works on both marine considered as the lifeline of the ancient kingdoms and non marine mollusca have been done in and modern cities of South India. The Cauvery Tamil Nadu by various workers (Radha Krishna, estuary, located along the east coast of India, is and Janakiram, 1975; Jayaram et al., 1982; a part of the Cauvery river basin (Ramanathan Mookherjee, 1985; Benjamin et al., 2009 etc.). et al., 1988). The river bifurcates into two large However there is lack of information regarding branches, the Kollidam (Coleroon) and Cauvery its biosystematics and distribution. Till at Grand Anicut (a dam near Trichirapalli). now, no studies have been taken up so far in these aspects. Hence, the present study taken up to fill Mollusca is one of the most diverse groups some lacunae by giving some needed information of on the planet, with at least 50,000 regarding molluscan fauna of the estuary. living species and also second only to Arthropoda in numerical abundance (Wikipedia: January, MATERIALS AND METHODS 2014). A part of almost every ecosystem in the The studied materials were collected from world, molluscs is extremely important members Cauvery estuary during the survey under the of many ecological communities. They have project on “Ichthyofauna of Cauvery Estuary, colonized and adapted all possible habitats Tamil Nadu and India w.s.r. to their Ecology, from deep sea to high mountains.They are more Diversity, and distribution pattern” during 2008- abundant in the littoral zones of tropical seas. 2010. Morphology and taxonomy of 129 examples 132 Rec. zool. Surv. India from the NZC of the centre were studied bio- Family BUCCINIDAE systematically using relevant literatures and Genus Schumacher, 1817 registered. The classification followed is that of 11. Babylonia spirata (Linnaeus) Vaught (1989). Family MELONGIENIDAE SYSTEMATIC LIST OF Genus Pugilina Schumacher, 1817 Phylum MOLLUSCA 12. Pugilina (Hemifusus) cochlidium (Linnaeus) Sub Class PROSOBRANCHIA Family MARGINELLIDAE Class GASTROPODA Genus Marginella Lamarck, 1799 Order MESOGASTROPODA 13. Marginella angustata (Sowerby, 1846) Super Family CERITHOIDEA SYSTEMATIC LIST OF BIVALVIA Family Order ARCOIDA Genus Montfort 1810 Super Family ARCOIDEA 1. Telescopium telescopium (Linn., 1758) Family ARCIDAE Family Genus Anadara Gray, 1847 Genus Tenomelania O. Fisher, 1885 1. Anadara (Scapharca) inaequivalvis (Bruguiere, 1792) 2. Stenomelania torulosa (Bruguiere) 2. Anadara (Scapharca) deyrollei (Joussaeume, Family 1883) Genus Lamarck, 1799 Order OSTREOIDA 3. Turritella attenuata (Reeve, 1849) Super Family OSTREOIDEA 4. Turrietella duplicata (Linn., 1758) Family OSTREIDAE Super Family Genus Crassostrea Sacco, 1897 Family 3. Crassostrea cutackensis (Newton and Smith, 1912) Genus Bruennich, 1722 Genus Saccostrea Dollfus and 5. Tonna dolium (Linn., 1758) Dautenberg, 1920 Family FICIDAE 4. Saccostrea cucullata (Born) Genus Ficus Roeding, 1798 Super Family PECTINOIDEA 6. Ficus variegata Roeding Family PECTINIDAE 7. Ficus gracilis (Sowerby) Genus Chlamys Roeding, 1798 Order 5. Chlam (Argopecten) tranquebaria (Gmelin, 1791) Super Family MURICOIDEA ORDER VENEROIDA Family Super Family CARDIOIDEA

Genus Linnaeus, 1758 Family Cardiidae 8. Murex tribulus Linnaeus Genus Acanthocardia J.E. Gray, 1851 9. Murex carbonnieri (Jousseaume) 6. Acanthocardia coronata (Schroeter, 1788) Genus Rapana Schumacher, 1817 Genus Trachycardium Moerch, 1853 10. Rapana rapiformes (Born) 7. Trachycardium asiaticum (Bruguiere) GURUMAYUM and KOSYGIN : On a collection of some mollusca from Cauvery estuary, Tamil Nadu 133

Super Family MACTROIDEA 2003. Telescopium telescopium: Subba Rao, Rec. zool. Surv. India, Occ. Paper No. 192: 136. Pl. 22, Fig. 3. Family MACTRIDAE Material examined: 1 Genus Mactra Linnaeus, 1758 8. Mactra (Mactrinula) laevis Chemnitz Measurement: Length: 2.4 cm Breadth: 1.0 cm. Super Family TELLINOIDEA Diagnosis: Shell very large, strongly conical and elevated, heavy and thick, about 14-16 whorls, Family DONACIDAE sutures not distinct. small and rounded, Genus Linnaeus, 1758 Donax solid, strongly twisted and channeled, 9. Donax (Hecuba) scortum (Lin) outer thickened, extended anteriorly as a flare 10. Donax (Latona) cuneatus Lin over siphonal canal. Super Family VENEROIDEA Distribution: Andhra Pradesh, Andaman and Family VENEROIDAE Nicobar Islands; Gujarat, Kerala; Puducherry, Genus Sunetta Link, 1807 Odisha, Tamil Nadu, West Bengal. 11. Sunetta meroe (Lin) Family THIARIDAE 12. Sunetta scripta (Lin) Genus Stenomelania O. Fisher, 1885 Genus Meretrix Lamarck, 1799 2. Stenomelania torulosa (Bruguiere) 13. Meretrix casta (Gmelin) 1789. Bulimus torulosa Bruguiere. Linnaeus, Encycl. Meth. Vers., 1: 332. Genus Marcia H. & A. Adams, 1857 1989. Stenomelania (Stenomelania). Subba Rao, Handbook 14. Marcia pinguis (Schroeter) of Freshwater Molluscs of India, p. 100, Fig. 202. Genus Lioconcha (Lioconcha) Mörch, 1853 Material examined: 5 15. Lioconcha sp. Measurement: Length: 2.0-7.4 cm Breadth: SYSTEMATIC ACCOUNT 0.8-1.8 cm. A Classified list of 28 mollusca species, Diagnosis: Shell thick, elongate and turreted, arranged systematically along with Systematic number of whorls 12-14, with strong spiral accounts is given in this report. The measurement sculpture broken up by transverse lines into (in cm), diagnosis, number of examples collected, rectangular nodules, aperture pyriform, pointed distribution of the species, along with remarks on above and rounded below, columellar side each species is given. All the species reported is somewhat twisted and curved to the right, outer available in the National Zoological Collection lip crenulated. of Estuarine biology Regional Station, ZSI, Gopalpur-on-Sea. Distribution: Andaman, Andhra Pradesh and Tamil Nadu. Phylum MOLLUSCA Family TURRITELLIDAE Subclass PROSOBRANCHIA Genus Turritella Lamarck, 1799 Class GASTROPODA 3. Turritella duplicata (Linnaeus) Order MESOGASTROPODA 1750. Turbo duplicata Linnaeus. Syst. Nat., ed. 12: 1239. Super Family 2000. Turritella duplicata, Subba Rao and Dey, Rec. zool. Family POTAMIDIDAE Surv. India, Occ. Paper No. 187: 53. Genus Telescopium Montfort 1810 Material examined: 8 1. Telescopium telescopium (Linnaeus) Measurement: Length: 6.2-7.8 cm Breadth: 1750. Trochus telescopium Linnaeus. Syst. Nat., ed. 10: 760. 1.5-2.0 cm. 134 Rec. zool. Surv. India

Diagnosis: Shell large, elongated with 18-20 and occasionally intermediate threads on the whorls, earlier whorls convex with many fine penultimate . Ornamented with quadrate or spiral ridges, the central ridge become elevated rectangular reddish brown spot upon the spiral into a strong keel in the subsequent 6-7 whorls cords. and spiral ridges become obsolete. The whorls at Distribution: Andhra Pradesh, Andaman and both end rounded and those in the middle sharply Nicobar Islands, Maharashtra, Odisha, Tamil angulated. Nadu, West Bengal. Distribution: Andhra Pradesh, Andaman Family FICIDAE Islands, , Maharashtra, Odisha, Puducherry, Genus Ficus Roeding, 1798 Tamil Nadu. 6. Ficus variegata (Roiding) 4. Turritella attenuata Reeve 1798. Ficus variegata Roiding. Mus. Bolten, p.148, sp. No. 1849. Turritella attenuata Reeve, Conch. Icon, 5: Turritella 1852. sp. No. 4. Pl.1, fig. 4. 2003. Ficus gracilis: Subba Rao, Rec. zool. Surv. India, Occ. Paper No. 192: 200 Pl. 42, Figs. 5-8. 2003. Turritella attenuata Subba Rao, Rec. zool. Surv. India, Occ. Paper No. 192: 1. Pl. 22, Fig. 140, pl. 23, fig. 1. Material examined: 3 Material examined: 4 Measurement: Length: 3.1-7.0 cm Breadth: Measurement: Length: 10.0-10.1 cm Breadth: 2.0-4.3 cm. 1.8-2.3 cm. Diagnosis: Shell is large and more globes, bulbous at the shoulder, having low and depressed Diagnosis: Shell elongated, large and attenuate ; aperture wide and long, columella concave, with 14-15 rounded whorls; aperture sinuate; siphonal canal recurved in the left, sculptured with sculpture with raised spiral striation almost equal high spiral ridges with deep grooves in the inter in earlier whorls and in later the middle striations space. become stronger and other weak and obsolete; Distribution: India: Andhra Pradesh, Nicobar whorls strongly keeled in the middle with slopping Islands, Odisha, Puducherry, Tamil Nadu, West upper part and curved lower part. Bengal. Distribution: Andhra Pradesh, Odisha, 7. Ficus gracilis (Sowerby) Puducherry, Tamil Nadu, West Bengal. 1825. Ficus gracilis Sowerby, Cat. Tank, Pl 17. Super Family TONNOIDEA 2003. Ficus gracilis: Subba Rao, Rec. zool. Surv. India, Family TONNIDAE Occ. Paper No. 192: 199 Pl. 42, Figs. 1-4. Material examined: 1 Genus Tonna Bruennich, 1722 Measurement: Length: 5.3 cm Breadth: 5. Tonna dolium (Linnaeus) 2.9 cm. 1758. dolium Linnaeus, Syst. Nat., ed. 10: 140. Diagnosis: Shell large having elongated body 2003. Tonna dolium. Subba Rao, Rec. zool. Surv. India, whorl with slightly elevated spire; sculptured Occ. Paper No. 192: 195. Pl. 41, Fig 9 with strong, flat, widely spaced spiral cords and Material examined: 1 smaller axial cords; aperture long and wide, outer Measurement: Length: 5.5 cm Breadth: 3.3 cm. lip slightly thickened; columella almost straight Diagnosis: Shell large and globose, thin, suture with a curve in the central; siphonal canal broad canaliculated, spire low, aperture very wide, outer and long. lip thin, columella almost straight, umbilicus Distribution: Andhra Pradesh, Nicobar Islands, open and deep, sculpture with 2 to 4 spiral cord Odisha, Puducherry, West Bengal. GURUMAYUM and KOSYGIN : On a collection of some mollusca from Cauvery estuary, Tamil Nadu 135

Order NEOGASTROPODA to two third of its length, gradually decreases in Super Family MURICOIDEA length. Family MURICIDAE Distribution: Andhra Pradesh, Andaman and Nicobar Islands, Gujarat, Karnataka, Kerala, Genus Murex Linnaeus, 1758 Maharashtra, Odisha, Tamil Nadu. 8. Murex tribulus Linnaeus Genus Rapana Schumacher, 1817 1758. Murex tribulus Linnaeus, Syst. Nat., ed. 10: 746. 10. Rapana rapiformes (Born) 2003. Murex tribulus Subba Rao, Rec. zool. Surv. India, Occ. Paper No. 192: 230, Pl. 53, Fig. 10. 1788. Murex rapiformes Born. Index rerum natur. Musei. Caes, Vindob., Pl. 1. Material examined: 5 2003. Murex rapiformes: Subba Rao, Rec. zool. Surv. India, Measurement: Length: 4.5-8.9 cm Breadth: Occ. Paper No. 192: 236, Pl. 56, Figs. 3. 2-4 cm. Material examined: 2 Diagnosis: Shell club shaped, spire high Measurement: Length: 6.2-6.9 cm Breadth: consists of 6-7 whorls, protoconch three and 5.1-6.6 cm. half whorls, sides evenly curved, smooth, suture Diagnosis: Shell large, pyriform, spire very deep and compressed. Aperture large, sub circular, low, with four to five whorls, suture deep and sulcus broad and shallow, outer lip erect with canaliculated, large and inflated. crenulation on the lower part, sculpture with Aperture wide and oval, outer lip margin three spinose, varices on the body whorl with 3-4 denticulate, interior lirate, wide and deep strongly nodulose axial costae; siphonal canal with umbilicus, canal short and widely open. Sculptured 7 spines, decreased in size towards the anterior with three nodules spiral ridges, the row on the end. shoulder bear fifteen open, blunt hollow spines. Distribution: Andhra Pradesh, Andaman and Distribution: India: Andhra Pradesh, Andaman Nicobar Islands, Gujarat, Kerala, Odisha, Tamil and Nicobar Islands, Gujarat, Lakshadweep, Nadu, West Bengal. Odisha, Puducherry, Tamil Nadu. 9. Murex carbonnieri (Jousseaume) Family MELONGENIDAE 1881. Acupurpurea carbonnieri Jousseaume, Length Naturliste, 44: 345. Genus Pugilina Schumacher, 1817 1993. Murx carbonnieri , Subba Rao, Rec. zool. Surv. India. 11. Pugilina (Hemifusus) cochlidium Occ. Paper No. 153: 33. pl. 4. (Linnaeus) Material examined: 1 1758. Murex cochlidium Linnaeus Sys, Nat., ed: 10: 753 Measurement: Length: 8.9 cm Breadth: 4 cm. 2003. Pugilina (Hemifusus) cochlidium: Subba Rao, Rec. zool. Surv. India, Occ. Paper No. 192: 274, Pl. 66, Diagnosis: Shell club shaped, spire elevated, Figs. 3 & 4. consist of 7-9 whorls; whorls subangulate, suture Material examined: 4 simple, deep, crossed by growth lamellae; aperture acute, ovate, outerlip margin crenulated, lower part Measurement: Length: 5.4-8.6 cm Breadth: with small labial tooth, inner lip partly adherent on 3.2-4.9 cm. posterior, body whorl large, preceding the whorls Diagnosis: Shell large, pear shaped solid and along with the body whorl with three prominent heavy, whorls angular, concave from suture to varices, provided with long spines, shoulder spines shoulder. Aperture narrow and elongate, outer lip large, open straight curved terminally, sculpture with obsolete ridges, columella without any fold, consists of three prominent spiral cords; siphonal anterior canal short and broadly open, very narrow canal and cords, provided with straight spines up and shallow umbilicus, strong fasiole. 136 Rec. zool. Surv. India

Distribution: India: Andhra Pradesh, Andaman SYSTEMATIC ACCOUNT and Nicobar Islands, Gujarat, Maharashtra, Odisha, OF BIVALVIA Tamil Nadu, West Bengal. Class BIVALVIA Family BUCCINIDAE Order ARCOIDA Genus Babylonia Schumacher, 1817 Super Family ARCOIDEA 12. Babylonia spirata (Linnaeus) Family ARCIDAE 1758. Buccinum spirata, Syst. Nat. ed 10: 753 Genus Anadara Gray, 1847 2000. Buccinum spirata: Subba Rao and Dey, Rec. zool. 1. Anadara (Scapharca) inaequivalvis Surv. India, Occ. Paper No. 187: 116. (Bruguiere) Material examined: 1 1792. Arca inaequivalvis (Bruguere). Encyl. Meth. Vers., 1: Measurement: Length: 5.0 cm Breadth: 106, pl. 305. 3.2 cm. Material examined: 21 valves Diagnosis: Shell medium in size, solid, ovate, Measurements: Length: 4-5.1 cm Height: heavy, spire elongate having inflated body whorl, 3.5-4 cm. sulcus channeled and deep; aperture ovate, large; Diagnosis: Shell inequivalve, sub quadrate, outer lip sharp and smooth, strongly flexed at top, sculpture with 34/35 flat radial ribs; interstices umbilicus broad and deep; anterior canal in the latticed with raised lines; hinge plate linear, distal form of a oblique notch, posterior canal well teeth larger than central; white brown periostracum developed, broader by parietal callus; light brown of dense short bristles. blotches on the body surface. Distribution: India, Andhra Pradesh, Andaman Islands, Goa, Gujarat, Kerala, Maharashtra, Distribution: Tamil Nadu, Andhra Pradesh, Odisha, Tamil Nadu. Andaman Islands, Goa, Gujarat, Kerala, Maharashtra, Odisha. 2. Anadara (Scapharca) deyrollei Joussaeume 1883. Anadara deyrollei Joussaeume, Length Natura liste, Family MARGINELLIDAE Islammae, p. 191. Genus Marginella Lamarck Material examined: 3 valves 13. Marginella angustata Sowerby Measurements: Length: 1.4-2.3 cm Height: 1846. Marginella angustata Sowerby, Thes. Conch., 1: 2.4-4.2 cm. Marginella, sp. no. 399, pl, fig., 169, 170. Diagnosis: Shell elongate and ovate, ineqivalve, 2000. Marginella angustata : Subba Rao and Dey, Rec. zool. side angulated at the dorsal margin, posterior side surv. India, Occ. Paper No. 187: 141. extended; sculpture with 32-35 radial ribs; umbone Material examined: 1 elevated. Measurement: Length: 2 cm Breadth: 1.2 cm Distribution: Andhra Pradesh, Maharashtra, Odisha, Tamil Nadu, West Bengal. Diagnosis: Shell small, cylindrical ovate; spire calloused and flat; aperture narrow, outer lip Order OSTREOIDA thickened and smooth, columella with four oblique Super Family OSTREOIDEA folds at the anterior end and the anterior most Family OSTREIDAE smallest; surface smooth, ash-white with grayish Genus Crassostrea Sacco, 1897 brown spiral bands crossed by bluish axial lines. 3. Crassostrea cuttackensis (Newton & Smith) Distribution: Andhra Pradesh, Andaman Island, 1912. Crassostrea graphoides var. cuttackensis Newton & Maharashtra, Lakshadweep, Odisha, Puducherry, Smith, Rec. Geol. Surv. India, 42(1): 13, pl. 7 & 8, Tamil Nadu. figs. A & Breadth. GURUMAYUM and KOSYGIN : On a collection of some mollusca from Cauvery estuary, Tamil Nadu 137

Material examined: 1 valve prominent; variable in colour with white irregular Measurements: Length: 2.8 cm Height: 2 cm patches. Diagnosis: Shell very heavy, bulky, irregularly Distribution: India: Andhra Pradesh, Andaman subcircular to elongate; externally whitish in and Nicobar Islands, Gujarat, Maharashtra, Odisha, colour, internally lustrous white; inequivalve; Tamil Nadu. outer surface with radial folds or ribs which Order VENEROIDA may affect the shell margin; hinge without teeth. Super Family CARDIOIDEA Postulose chomata often in right valve. Family CARDIIDAE Distribution: Andhra Pradesh, Andaman and Nicobar Islands,Goa, Gujarat, Karnataka, Kerala, Genus Acanthocardia Gray Maharashtra, Odisha, Tamil Nadu. 6. Acanthocardia coronata (Schroeter, 1788) Genus Saccostrea Dollfus and 1786. Cardium coronatum Scroeter, Encl. Conchyl., 3: 53, Dautenberg, 1920 sp. 4, pl. 7, fig. 13. 4. Saccostrea cucullata (Born) Material examined: 1 valve 1778. Ostrea cucullata Born, Index Rerum Naturalism Musei Measurements: Length: 2.5 cm Height: Cae. Vindob., 1778: 100, figs. 11-12. 2.9 cm. Material examined: 1 valve Diagnosis: Shell sub orbicular, margin nearly Measurements: Length: 2 cm Height: 2.3 cm. rounded, umbo central, elevated; sculpture with 34- Diagnosis: Shell stout, very variable in shape 38 very low, radial ribs, bearing calcarious raised and size and very inequivalve; chomata present flanged on their posterior margins, interdigitate at all around the internal shell margins; outer surface the end; white saffron in colour with weak shades of right valve smoothes, sometimes with distinct of orange pink posteriorly. radial ribs; abductor muscle scar kidney shaped, Distribution: Andhra Pradesh, Andaman and more or less posteroventral in position. Nicobar Islands, Gujarat, Maharashtra, Odisha and Distribution: India: Andhra Pradesh, Andaman Tamil Nadu. and Nicobar Islands, Gujarat, Kerala, Maharashtra, Genus Trachycardium Moerch, 1853 Odisha, Tamil Nadu, West Bengal. 7. Trachycardium asiaticum (Bruguiere) Super Family PECTINOIDEA 1792. Cardium asiaticum Bruguiere, Encyl. Meth. Vers., 1: Family PECTINIDAE 224. Genus Chlamys Roeding, 1798 Material examined: 7valves 5. Chlamys (Argopecten) tranquebarica Measurements: Length: 2.2-5.3 cm Height: (Gmelin) 2-5.2 cm 1791. Ostrea tranquebarea Gmelin, Syst. Nat., ed. 13: Diagnosis: Shell globose, umbone anterior, 3328. elevated; sculpture with 34-36 close set radial Material examined: 1 valve ribs, smooth around umbo but lamelliferous Measurements: Length: 1.6 cm Height: 1.3 cm towards the posterior margins; hinge condense Diagnosis: Shell solid, medium sized, length anteriorly, laterials close to the cardinals, margin almost equal to high, left valve more convex than crenulated.. right; sculptured with 20-24 rounded radial ribs, Distribution: Andhra Pradesh, Andaman and gradually narrow towards umbo; almost smooth; Nicobar Islands, Gujarat, Maharashtra, Tamil anterior ear larger than posterior one, byssal orifice Nadu, West Bengal. 138 Rec. zool. Surv. India

Super Family MACTROIDEA both the valves; sculpture with fine concentric Family MACTRIDAE striae, rugose on the posterior end; purple with white band. Genus Mactra Linnaeus, 1758 Distribution: Andhra Pradesh, Andaman and 8. Mactra (Mactrinula) laevis Chemnitz Nicobar Islands Gujarat, Maharashtra, Odisha, 1853. Mactra laevis Chemnitz, Conch. Cab., 6: 214, pl. 21, Tamil Nadu, West Bengal. figs. 205 & 206 Super Family VENEROIDEA Material examined: 4 valves Family VENEROIDAE Measurements: Length: 4.9-6.9 cm Height: 1.6-3.1 cm. Genus Sunetta Link, 1807 11. (Linnaeus) Diagnosis: Shell ovately triangular, Sunetta meroe inequlateral; anterior side rather produced, 1758. Venus meroe. Linnaeus, Syst. Nat., 10: 687. rounded, posterior truncated; lunule lanceolate, Material examined: 1 valve ovate and excavated; sinus of the middle very Measurements: Length: 4 cm Height: 3 cm short, obtuse at the top, obliquely triangular. Diagnosis: Shell sub ovate, anterior end Distribution: Andhra Pradesh, Goa, Odisha, rounded, posterior sub truncate; umbo posterior, Tamil Nadu. beak slightly in front of mid line; sculpture with Super Family TELLINOIDEA prominent concentric ridges; escutcheon deeply excavated; beige to lilac with dark brown or yellow Family Donacidae brown zig-zag lines throughout the body; inner Genus Donax Linnaeus, 1758 ventral margin crenulated. 9. Donax (Hecuba) scortum (Lin) Distribution: Andhra Pradesh, Maharashtra, 1758. Venus scortum Linnaeus, Syst. Nat., ed., 10: 686. Odisha, Puducherry, Tamil Nadu. Material examined: 4 valves 12. Sunetta scripta (Lin) Measurements: Length: 4.9-6 cm Height: 3.2- 1758. Donax scripta Linnaeus, Syst. Nat., 10: 683. 3.5 cm. Material examined: 1 valve Diagnosis: Shell triangularly oblong; umbo Measurements: Length: 1.1 cm Height: 0.9 cm. posterior, elevated and pointed; ligament short; Diagnosis: Shell wedge shaped; umbo posterior, lunule very prominent, wide and equal on both the beak slightly in front of mid lines; anterior end valves; sculpture with prominent concentric striae, rounded, posterior truncate; sculpture smooth only radial striae prominent; dirty white in colour. with growth lines; escutcheon deeply excavated; Distribution: Andhra Pradesh, Goa, Gujarat, variable in colour pattern, white or beige, lilac Karnataka, Kerala, Odisha, Puducherry, Tamil with brown violet zig-zag lines or with deep violet Nadu, West Bengal. patches; inner ventral margin crenulated. 10. Donax (Latona) cuneatus Lin Distribution: Andhra Pradesh. Goa, Gujarat, 1758. Donax cuneatus Linnaeus, Syst. Nat., ed. 10: 683. Karnatak, Kerala, Odisha, Tamil Nadu. Material examined: 2 valves Genus Meretrix Lamarck, 1799 Measurements: Length: 4.4 cm Height: 13. Meretrix casta (Gmelin) 2.7 cm. 1791. Venus casta Gmelin, Syst. Nat., 13: 3278. Diagnosis: Shell subtraingularly oblong; Material examined: 26 valves compressed, shining; umbo posterior and elevated; Measurements: Length: 3.3-5.6 cm Height: ligament short and dark brown; lunule present on 2.9-5 cm GURUMAYUM and KOSYGIN : On a collection of some mollusca from Cauvery estuary, Tamil Nadu 139

Diagnosis: Shell solid but less heavy than DISCUSSION M. Meritrix; umbo slightly anterior, beak more A total of 28 mollusca species belonging attenuated; lunule well developed; variable in to six Order and 16 families were recorded shape and colour; muscle scars well impressed, from the study. Of this 28 species, 13 belong posterior abductor scar slightly larger than anterior; to Class Gastropoda and remaining 15 belongs anterior cardinal teeth more strong on left valve; pallial line well impressed, pallial sinus absent. to Bivalvia. It is found that most of the species studied are marine in habitat, however about ten Distribution: Andhra Pradesh, Karnataka, species which are truly estuarine species viz. Kerala, Odisha, Puducherry, Tamil Nadu, Telescopium telescopium, Thiara (Stenomelania) Genus Marcia H. & A. Adams, 1857 torulosa, Anadara (Scapharca) inaequivalvis, 14. Marcia pinguis (Schroeter) Anadara (Scapharca) m deyrollei, Crassostrea 1788. Venus pinguis Schroeter, Nomen. Register, 10: 112. cutackensis, Saccostrea cucullata, Donax scortum, Material examined: 1 valve Donax (Latona) cuneatus Meretrix casta, Marcia pinguis were also recorded during the study from Measurements: Length: 4.8 cm Height: 3.9 cm. the estuary. Diagnosis: Shell sub ovate, anterior rounded, posterior sub truncate; umbo anterior, beak more SUMMARY attenuated; lunule well defined, depressed and Taxonomy and biosystematics of 112 molluscan cordate; sculpture smooth with growth lines only; examples collected from Cauvery estuary which abductor muscle scars almost equal; pallial line was deposited in National zoological collection deep, pallial sinus well developed; beige with of the Estuarine Biology Regional Centre, EBRC brown, umbonal region grey. were studied. A total of 28 mollusca species Distribution: Andhra Pradesh, Andaman and belonging to six order and 16 families were Nicobar Islands, Karnataka, Odisha, Puducherry, recorded from the study. Of this 28 species 13 Tamil Nadu. belongs to Class Gastropods and remaining 15 Genus Lioconcha Morch belongs to Bivalvia. It is found that most of the 15. Lioconcha sp. species studied are marine in habitat and only about ten species are truly estuarine species. Material examined: 1 valve Measurements: Length: 4.9 cm Height: 4.1 cm. ACKNOWLEDGMENTS Diagnosis: Shell rounded-ovate, umbones The author is grateful to Director, Zoological slightly anterior and rounded post dorsal margin, Survey of India and Officer-in-Charge, Estuarine outer surface glossy and very smooth with some Biology Regional Centre (EBRC), ZSI, fine dark patterns. Gopalpur-on-Sea, Odisha for providing necessary Distribution: Tamil Nadu. facilities.

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Manuscript Received : 26th June, 2014; Accepted : 9th October, 2014.