REGARDING DISTRIBUTION OF DIFFERENT SPECIES OF GASTROPODS IN INDIA

1. KERALA UNIVERSITY OF FISHERIES ANDOCEAN STUDIES
DEPARTMENT : FISHERIES RESOURCE MANAGEMENT
COURSE TITLE : MARINE ECOSYSTEMS , BIODIVERSITY AND CONSERVATION
COURSE NO : FRM-503
RM 51 TOPIC : TAXONOMY, DIVERSITY AND DISTRIBUTION OF
GASTROPODS WITH SPECIAL REFERENCE TO INDIA
SUBMITTED BY
RAVI KIRAN PAMISETTY
FSM-2020-20-07

2. PHYLUM - MOLLUSCA
• Includes all snails and slugs ,clams, oysters, scallops, geoducks, mussels
• Mollusca is the second-largest phylum of invertebrate animals after the arthropoda.
• Around 85,000 extant species of molluscs are recognized.
• Molluscs are terrestrial or aquatic ( F.W & M.W)
• A total of 3,271 species of molluscs are distributed along the Indian coast which
includes 220 families and 591 genera
• Molluscs are the largest marine phylum, comprising about 23% of all the named
marine organisims
• They are bilaterally symmetrical and coelomates animals.
• Body covered with calcareous shell and is unsegmented with distinctive head ,
muscular foot ,visceral mass
• Except cephalopods circulatory system is open type.

3. • Molluscs are classified into classes based on symmetry , shell , mantle
,gills , nervous system and radula.

5. Class- gastropoda
• The gastropods commonly known as snails and slugs
• The class Gastropoda contains a vast total of named species, second only to
the insects in overall number.
• they are most highly diversified class in the phylum mollusca, with 65,000 to
80,000 living snail and slug species.
• There are 444 recently extinct species of gastropods (extinct since the year
1500), 18 species that are now extinct in the wild (but still existing in captivity)
and 69 "possibly extinct" species.
• About 1900 species of gastropods have been reported from India
• In marine habitats, the continental slope and the continental rise are home to
the highest diversity of marine gastropods.
• Gastropods are asymmetrical molluscs that underwent torsion.

6. Gastropods are classified mainly into three sub classes
1.Prosobranchia
It include the majority of marine snails, among
them conches, cones, cowries, limpets, murexes, periwinkles, volutes and
whelks
2. Opisthobranchia
It includes sacoglossans, anaspidean sea hares, pelagic sea angels, sea
butterflies etc..,
3. Pulmonata
It includes snails and slugs

7. List of commercially exploited gastropods from Indian waters

10. Babylonia spirata (whelk)
Mainly found along tamilnadu coast and also in west coast
• They are mostly carnivorous and scavengers.
• Shell is thick, smooth with distinctive spiral and conical in
shape. The shell coloration and pattern of colour design is
variable from plain brown to white with brown or orange
spots.
• The meat is edible and the shell is used in the shell craft
industries.

11. Tectus niloticus
• This marine species is widespread in the Indo-Pacific region ,
mainly found in the Andaman and Nicobar Islands.
• live in shallow areas on intertidal reef flats, along the reef crest
or on reef slopes
feed on very small plants and filamentous algae grazed on coral
and rocks.
conical in shape ,Outer surface of the shell is white with many
reddish-brown longitudinal bands

12. Chanks (Turbinella pyrum)
Turbinella pyrum, common names the chank shell, sacred
chank or chank, also known as the divine conch
Major chank resources occur in the Gulf of Manner, particularly
along the Ramanathapuram – Tirunelveli coast. Other areas are
Tanjavur, South Arcot and Chingelpet in Tamil Nadu,
Trivandrum coast in Kerala, the Gulf of Kutch in Gujarat and the
Andaman's.
 The shell is huge, thick, pear-shaped and coated with a brownish
horny periostracum

13. Lambis lambis ( spider conch)
• These lives in mangrove areas, as well as reef flats and coral-
rubble bottoms in shallow water
• Lambis lambis is known to be herbivorous, feeding on
fine red algae.
• The five-fingered chank is large, thick and heavy with a
slightly high and pointed spire.
• Dorsal surface of body is rough, with uneven spiral cords and
2 or 3 spiral rows of blunt tubercles, forming large knobs on
the shoulder.
• Mainly distributed along east coast

14. Agaronia gibbosa
• It is mostly found on southeren parts of east and west
coast.
• Mostly found on Coastal, sandy bottom.
• Colour pale yellowish brown with a prominent yellow
band at the base, mottled with black spots,Sometimes
whitish with zig zag transspiral brownish bands, spire
and column yellowish white, aperture bluish white.

15. Cypraea tigris
• Its mainly found along east coast and Lakshadweep island.
• Carnivorous, the adult tiger cowrie eats coral and
various invertebrates, while juveniles eat algae.
• Roughly egg-shaped and dextral, the glossy shell is large and
heavy for a cowry. The ventral side is white or whitish, and
the shell opening is lined with tooth-like serrations.

16. Chicoreus virgineus
• This species occurs in intertidal regions from the Red Sea to
the Bay of Bengal.
• Shell moderately large in size; fusiform; spire acute; body
whorl large and inflated
• colour pale brown with a slight pinkish band on middle of
body whorl; aperture white, margin of aperture pinkish
white.

17. Umbonium vestiarium (button tops)
• They can be found on eulittoral sand ,found mainly
in indo- pacific regions , in india along east coast
• The solid, rounded shells are up to 2 cm wide and
are more flattened and show a glossy, highly
variable and colourfully patterned exterior.

18. Conus glaucus ( glaucous cone)
These snails are predatory and venomous. They are capable
of "stinging" humans
• The color of the shell is bluish ash or very light chocolate,
with usually a lighter narrow central band, and numerous
short chocolate lines in revolving series.
• It is mostly found on southeren parts of
east and west coast.

19. IUCN RED LIST OF GASTROPODS
TOTAL number of gastropod species under IUCN red list = 7326
 EX - Extinct =267
 EW - Extinct in the Wild =14
 CR - Critically Endangered (includes CR(PE) and CR(PEW))=604
EN - Endangered =518
VU - Vulnerable=975
 LR/cd - Lower Risk/conservation dependent = 0
 NT - Near Threatened (includes LR/nt - Lower Risk/near threatened)=637
 DD - Data Deficient = 1648
 LC - Least Concern (includes LR/lc - Lower Risk/least concern = 2663

21. species of molluscs have been listed in the Indian Wildlife
(protection) Act, 1972, amended in 2001

22. THREATS
• Housing and urbanization
• Mining and quarrying.
• Tourism and recreational areas.
• Soil erosion and sedimentation.
• Global climatic change
• Habitat destruction and fragementation
• pollution

23. REFERENCES
• Mohamed, K S (2006) Molluscan Fisheries. In: Handbook of Fisheries
and Aquaculture. Ayyappan, S,(ed.) Indian Council of Agricultural
Research, New Delhi, pp. 116-134.
• Narasimham, K.A., V. Kripa and K. Balan (1993). Molluscan shellfish
resources of India An overview. Indian J. Fish. 40(1&2): 112-124.
• K. Sunil Mohamed and V. Venkatesan MARINE MOLLUSCAN DIVERSITY
IN INDIA - EXPLOITATION, CONSERVATION
• Appukuttan, K.K. 1996. Marine molluscs and their conservation. In
Marine BiodiversityConservation and Management. Central Marine
Fisheries Institute, Cochin, eds. N.G.Menon and C.S.G. Pillai.