Echinodermata: India
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Faunal Diversity in India: Echinodermata
This is an extract from FAUNAL DIVERSITY IN INDIA Edited by J. R. B. Alfred A. K. Das A. K. Sanyal. ENVIS Centre, Zoological Survey of India, Calcutta. 1998 ( J. R. B. Alfred was Director, Zoological Survey of India) |
Introduction
Echinoderms are characterised by a water vascular system of coelomic origin, with radiating canals and their projecting tubefeet or papillae. They have an endodermal calcareous skeleton of articulating plates (Crinoidea, Asteroidea and Ophiuroidea), box of rigidly fused plates (Echinoidea) or scattered microscopic spicules (Holothuroidea). The body is in general radially symmetrical with a few exceptions of bilateral symmetry. They are further characterised by pentamerous arrangement of body organs such as arms, tentacles, radial canals, gonads, etc.
Status Of The Taxon
Global and Indian Status
The phylum comprises over 6,000 extant species representing six classes. Echinoderm diversity of the world and that of India are shown in Table -1. Table -1 Number of Echinoderm taxa in the world and India Class Families (N) Genera (N) Species (N) World India World India World India Crinoidea 24 13 164 43 623 95 Asteroidea 35 20 318 81 1500 180 Ophiuroidea 17 15 275 67 2000 150 Echinoidea 47 28 230 79 950 150 Holothuroidea 25 14 154 62 1150 160 Total 148 90 1141 332 6223 765
Distribution
The ehinoderms occur from the intertidal region to great depths of all the world oceans. Their habitats include a variety of rocky, sandy, muddy and coral environments. Only the class Concentricycloidea comprising two nominal species under a single genus and a single family is not so far discovered from Indian waters. The enchinoderm diversity is not the same throughout Indian waters. Although some areas are yet to be explored thoroughly, the available data indicates certain regions with rich diversity as shown in Table 2. Table -2 Regions in India with rich echinoderm diversity
A greater part of the echinoderm fauna inhabits the shelf area up to 200 m. However, the deep water component varies from 37 to 47 per cent in different groups. BIOLOGICAL DIVERSITY AND ITS SPECIAL FEATURES Biological diversity of echinoderms has been shown in Tables -1 and 2. The adults of almost all the species are freeliving, while the males of some ophiuro~ds are epizoic on females. Some crinoids and ophiuroids are known to be epizoic on gorgonids and some are endozoic. A few species are frequently encountered among phytal fauna. The stalked crinoids (sea-lilies) inhabit the deeper waters and lead a sedentary life with their stalk fixed to the substratum. The unstalked crinoids (feather stars) are capable of free swimming, though most forms such as Tropiometra carinata and Lamprometra pa/mata can be found attached to the undersurface of rocks and corals or crawling on the bottom of shallow pools during ebb tide period. They mostly feed on the floating organisms caught in the mucous secretions of their pirmules.
Asteroides are inhabitants of both hard and soft substrata. Species of Astropecten inhabit soft substrata and often burrow onto the subsurface leaving a characteristic mark on the surface. ClIlcita, Lillckia, Asteropsis, Asterina, etc., inhabit rocky and coral environs. They are predominantly carnivorous, feeding on a variety of animals such as crabs, molluscs, coral polyps, etc. Ophiuroids are inhabitants of rocky, coral, sandy and algal habitats. Quite a few species of euryalids are epizoic on gorgonids. The tropicopolitan species, Ophiactis savignyi inhabits crevices in rocks, sponges and algae. The arnphiurid Amphiura tenuis lives deeply burried in the muddy habitats of the Sunderbans in West Bengal. Ophiuroids are carnivores and detritus feeders. They also feed on floating organisms and organic matter caught in the mucous secretions of the arms. Most regular echinoids (Toxopneustes, Colobocentrotus) occur in rocky and coral habitats while the sand dollars (Clypeaster) and heart-urchins (Lovenia) are inhabitants of soft substrata. The regular echinoids are herbivores, resorting to occasional omnivorous habit. Other echinoids are substrate feeders.
Though holothurians are common in the coral and rocky habitats, their preferred habitat is soft substratum at least for feeding visits. They pass large quantities of the sediment through their digestive system and subsist on its organic content. From the view point of science, echinoderms are a puzzling group with regard to their origin, diversity and evolution, as can be seen from the frequent changes in the views regarding these aspects right from the times of their discovery up to the present time.
Endemicity
The Indian echinoderms are constituents of Indo-West Pacific fauna with a wide zoogeographical range from East coast of Africa to Hawaii and Australia. Very few species have a limited distribution along the Indian and neighbouring coasts. There are several genera of Indian fauna such as Metrodira, Acanthaster, Ophiocomella, Stomopnellstes, etc., which are monotypic but not endemic to India. Several species are still known only by their original discovery from deep waters. However, some were later found to be occurring in other oceans also. As such, no endemicity can be attributed to Indian echinoderms.
Value
Economically only Holothuroidea are exploited on a commercial scale for export. More than 12 species of Holothurians belonging to the genera Actinopyga, Bolladscllia, Holotlluria, Sticllopus and Tllelenota are known to be of commercial importance. However, only three species, Bohadschia marmorata, Holotllllria scabra and H. spinifera are being exploited to a limited extent in the Gulf of Mannar. The potentiality of developing the industry at Lakshadweep and Andaman and Nicobar Islands and exploitation of sea-urchins, such as, Stomopnellstes and Tripneustes for the purpose are to be explored. Sea-urchin exploitation is limited and localised. Their cleaned tests with symmetrical ornamentation of ambulacral and interambulacral areas serve as decorative pieces. Research on the extracts of echinoderms for bio-active compounds has started only recently and there are already indications of their importance as potential sources of toxins and hormones. The holothurian extracts have been found to be useful in controlling the menace of starfishes in shelUish cultures.
Echinoderms are very sensitive to deteriorating environment. As such they are good indicators of healthy habitats. Their developmental stages, particularly of echinoids, can be successfully used in environmental monitoring studies. Echinoderms interact with the biotic and abiotic environment in a significant way. They extract calcium from the sea-water for building their skeleton which contributes to the bottom sediments of the ocean. The holothurians with their burrowing and feeding activity are good substrate reworkers and can be compared to earthworms of the terrestrial habitat. Many sea-urchins such as Stomopneustes, Diadema, Echinometra and Echinostrephlls live in bores in the rocks, often made by themselves or widening the existing depressions through abrasive action. Thus they contribute to the biodeterioration of the environment as well. Many echinoderms are involved in biological associations with a variety of faunal groups such as crustaceans, fish, polychaetes, etc. providing them food, shelter and substratum. Asteroids are mostly carnivorous, though other types of feeding are known. They are a menace in oyster and other shellfish cultures. The crown-of-thorns starfish, Acanthaster planci is a voracious carnivore preferring live coral polyps. When occurring in la,rge numbers, they can destroy vast areas of coral habitat beyond recovery until a few decades to come.
Several regular echinoids are herbivores. When migrating in large aggregations, they can denude vast areas of algal forests on the sea bottom or denude large rocky habitats of their algal cover. On Indian coast, the feeding rate of Stomopneustes variolaris during the pre-spawning period has been found to be more than the growth rate of the algae on which they feed. This however seems to be compensated by a very low feeding rate during the spawning and immediate post-spawning periods.
Threats
Most echinoderms inhabit only healthy habitats. Their absence indicates fouling of the environment because of organic enrichment with consequent depletion of oxygen. While the activity at even large fishing villages along the open coast has been found to be no nuisance to the environernnt, berthing facilities for a moderate number of mechanised fishing boats at harbours and narrow mouths of gulfs have been found to be a threat to the healthy habitats in the surroundings. Because of limited flushing and organic enrichment through accumulation of fish w~stes, the habitat becomes uninhabitable for echinoderms. In some places, echinoderm species which were once abundant are found to be absent subsequent to provision of such facilities.
They are also vulnerable to habitat destruction at shingle beds and coral environments. Indiscriminate collection and wanton disturbance by unguided enthusiatic amateurs cause considerable damage to the echinoderm populations, particularly of ecologically and economically important species.
In .addition, exploitation of corals and shells for domestic and industrial purposes or curio trade, not only deteriorate the environment, but also disturbs the natural balance of the community resulting in population explosion of unwanted or harmful species. This causes further damage to the community as well as the environment.
Conservation Strategies And Future Studies
Local authorities and institutions should generate awareness in the public, regarding the importance of the faunal wealth and natural habitats, check indiscriminate exploitation of fauna and damage to the habitats. Developmental projects also are to be so planned as to cause the least disturbance to the fragile habitats like gulfs, coral reefs and shingle beds.
Selective References
Echinodermata of the Indian Museum, Parts I-X (1899-1927), Calcutta. Reports on the echinoderm material collected by the R.I.M.5.Jnvestigator, by A. H. Clark, R. Koehler & C. Yaney. A Monograph of the existing Crinoidea, Vol. I The comatlliids. Parts 1 to 4c by A. H. Clark (1915-1950) and part 5 by A. H. Clark & A. M. Clark (1967). Bull U.S. natn. Mus., 82. Clark, A. M. & Rowe, F.W.E. (1971) Monograph of shallow-water Indo-west Pacific echinoderms. 238 pp. Brit. Mus. (N.H.); London. Clark, H. L. 1915. Catalogue of recent ophiurans. Mem. MilS. compo Zool. Harv., 2S : 165-376. Fisher, W. K. 1911-1930. Asteroidea of the North Pacific and adjacent waters. Bull. U.S. natan. Mus., 76 (1-3). Hyman, L. H. 1955. The Invertebrates, IV Echinodermata. 763 pp. McGraw Hill, N.Y. James, D. B. 1987. Research on Indian echinoderms-a review, J. mar. bioi. Ass. India, 2S : 91-109. Jansoux, M. & Lawrence, J. M. (Eds.) Echinoderm studies A. Baltema, Rotterdam. So far three volumes of the continuing series have been published in 1983, 1987 and 1989 respectively. Mortensen, Th. 1928-1951. Monograph of Echinoidea, Vol. I-V. Copenhagen.
Echinodermata
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Introduction
As conspicuous constituents of marine biota, echinoderms have been known since ancient times and have evoked a large literature. The name Echinodermata which is now applied to such forms commonly known as sea-lilies, starfish, sea-urchins, sea-cucumbers etc., was frrst used by Jacob Klein (1734) for some echinoids, denoting the spiny skinned organisms. However, Linnaeus (~758) in his Systema Naturae ignored the name and included the echinoderms known to him under Mollusca Later, Bruguiere (1791) separated them from Mollusca and made Echinodermata an order under Vermes. Although the bolothurians remained separated from other echonoderms, In 1801, Lamarck for the frrst time brought holothurians together with other echinoderms but placed Echinodennata under Radiata along with Coelenterata. This association persisted for a long time until Frey and Leuckart (1847) separated echinoderms from Radiata. Since then Echinodermata have been regarded as a distinct phylwn.
The echinoderms are characterised by radial symmetry almost invariably with pentamerous organisation of body organs, only holothurians and some echinoids having taken to bilateral symmetry. They are readily differentiated from the similarly radiate phyla by the coelom and higher level of organisation. The most conspicuous feature is their water-vascular system of coelomic natme and its radiating vessels and probUding tube feet or papillae. They further have a calcareous endoskeleton of articulating plates, rigid box-like test or scattered microscopic spicules. The body surface bears soft papillae, warts, calcareous granules or more commonly hard spines from which the name Echinodermata seems to have taken its origin.
The phylum has been divided into three subphyla comprising of 20 or more classes as per different views, of which, only the following six are extant
Subphylum Class
Crinozoa Crinoidea
Asterozoa Concentricycloidea Asteroidea Ophiuroidea
Echinozoa Echinoidea Holothuroidea
The phylum can be traced to Cambrian and five of the above mentioned were distinct by Ordovician while the recently discovered Concentricycloidea had probably originated in Jurassic as per the opinion of its authors.
The Crinoidea primarily have a cup-like body called theca from which the branched anns with their lateral pinnules radiate. The sea-lilies have a long jointed stalk with whorls of cirri at each node and live attached to the substratum, while the sea-feathers detach the stalk at the base retaining only the top most whorl of cirri for temporary attachment or crawling and lead a free moving life.
The recently discovered Concentricycloidea are flat discoid forms without distinct arms and with concentrically arranged water-vascular system including the tube feet and supporting skeletal
D. R. K. Sastry, Zoological SUlVey of India, 27, Iawaharlal Nehru Road, Calcutta 700 016. structures. This class is so far wholly represented by two living species : Xyloplax medusiformis Baker et al., 1986 from New Zealand and X. turnerae Rowe et al., 1988 from Bahamas.
The Asteroidea are flattened with a central disc and radiating arms, the latter not distinct in some. The ambulacral grooves are well formed and the metapinnules of Somasteroidea are reduced and highly modified.
The Ophiuroidea have a central disc and long brittle arms distinct froln the disc. The paired ambulacral plates are fused into a single vertebra and enclosed together with the ambulacral furrow in box-like segments formed of latgeral, dorsal and ventral ann plates with the tentacle-like tube feet protruding out through pores on the ventral side. The arms are highly branched in many Euryalae.
In Echinoidea the endoskeleton fonns a thick rigid box-like test enclosing all the visceral organs. The tube feet protrude out through the pores in the ambuJacral plates. The motUh is always on the lower side while the anus is situated above or on the oral side.
The Holothuroidea are oro-anally elongated cylindrical fonns with the mouth and anus situated at either end. The mouth is surrounded by highly modified tube feet called tentacles. The endoskeleton consists of scattered microscopic spicules of various forms.
The echhinoderms inhabit all the possible habitats right from the intertidal region up to the abyssal depths of about 10,000 m. of the marine environment. Their size also varies from a few millimetres as in the interstitial holothuriar.s to about 1.38 m. in diameter or 10 kg. in wet weight of certain asteroids or about 2 m. in length in some holothurians. Although the majority are benthic with crawling or bUlTowing mode of life, the sea-lilies are permanently attached to the substratum and the sea-feathers and abyssal holothmians are habitual swimmers for short distances while certain holothurians are entirely planktonic. The benthic forms inhabit the hard substrata such as rocks and corals or crawl or burrow into the soft sediment.
There are also fonns which are epizoic on gorgonids and others inhabiting the sponges and algae. Their feeding habits also vary greatly. The regular echinoids feed on algae and certain asteroids ~rapemicroscopic algal covering on rocks. The crinoids and basket stars exclusively feed on the fldating micro-organisms by trapping them in mucus or the branching arms. Most asteroids are carnivorous feeding chiefly on molluscs, crustaceans and coral polyps. Some ophiuroids trap the floating organic particles in mucus and convey them to the mouth. Most other echinoderms swallow the organic rich sediment while crawling or burrowing. The echinoderms are dioecious• with external fertilization and development through a free swimming planktonic larva characteristic of each group. Viviparity and brood protection are common in cold water inhabitants. Certain species are also known to be protandric. Some rare instances of hennaphroditism have also been reported.
The echinoderms constitute a very important component of the marine benthic biota of all depths. Numerically ophiuroids are the major constituent of some benthic communities, while holothurians contribute to about 90% of the total biomass at abyssal and hadal depths. Because of their characteristic int.ernal skeletal structure, echinodrems are one of the major groups extracting calcium from the ambient waters and contributing to the carbonate sediments of the ocean fioo(. The boring activity of some sea urchins into the rocks and coral conglomerates causes erosion of the hard substrata contributing to the development of soft habitats.
The holothurians with their burrowing and casting habits are comparable to the earthworms as substrate reworkers. The burrowing asteroids and irregular urchins also disturb the sediment considerably.
The varied feeding habits encountered in the group, make use of all types of food available in the environment ranging from attached algae and planktonic biota to the sedentary and bwrowing or creeping organisms and organic rich sediments and oozes. In addition, instances of scavenging are also not rare. While this ensures an important place for themselves in the complex food chain of the community, the more disastrous activity is by way of great damage to extensive coral reefs through voracious feeding by the sea-star, Aeanthaster plane; and to the algal beds by various herbivorous echinoids, affecting the community structure drastically and sometimes irreparably.
The ripe gonads of sea urchins and processed body wall of holothurians (beche-de-mer or tr~pang) are considered as delicacies in sev~parts of the world particularly in SE Asia. A very good beche-de-mer industry survives in the Gulf of Mannar area with possibilities for extending the same to other localities rich in holothurian resources. Attempts are also on the way to explore the echinoid resources of the Indian seas for a si~ilar exploitation. Sea urchin eggs are also a very handy material in the fields of experimental embryology, developmental physiology, pollution control etc. Recently, echinoderms are being extensively used in the biomedical research for the extraction of various compounds of pharmocological importance.
In addition, dried asteroid specimens and cleaned tests of echinoids with their captivating symmetry and alluring ornamentation serve as decorative pieces. The tests of echinoids are particularly used in making various curios such as paper-weights, lamp shades, ashtrays etc. and as bases for various other curios.
Historical Resume
Although the frrst report on Indian echinoderms dates as far back to as 1743, our knowledge of the group greatly increased in the late 19th century with the launching of the Marine Survey programme aboard the R.I.M.S. Investigator in 1881 and the almost simultaneous interest shown by the Madras Government Museum in the chank and pearl fishery of the Gulf of Mannar as well as the general fauna of the area, there being very few reports during the intervening period.
i)Pre-1900
It was in 1743 when the first report on Indian echinoderms was made by Plancus and Gualtire from Goa and the next in 1830 by Colliere on the beche-de-mer. Subsequently, the accounts of Mueller (1849), Luetken (1865, 1872) and Marktanner-Turneretscher (1887) included a few new species from the Bay of Bengal. In the field of Palaeontology,Stolickzka (1873) reported on the cretaceous echinoderms of South India, while Duncan and Sladen (1883) and Blanford (1887) studied the fossil echinoids of Gujarat and Rajasthan respectively.
The extensive echinoderm collections made by the scientists of Marine Survey through
R.I.M.S. Investigator from various coastal and offshore areas were studied by several workers. Simultaneously the Madras Government Museum took interest in the fauna of Gulf of Mannar during a study of chank and pearl fishery of the area. Day (1883) fust catalogued the echinodenn exhibits from the Investigator in the Indian section at the International Fish Exhibition. Alcock (1893-1895), Anderson (1894, 1907), Walsh (1891) reported on the earlier collections of the Investigator. Koehler (1897, 1898) frrst reported on the entire ophiuroid collections. These have been reprinted under Echinoderma 0/the Indian Museum with additional information on subsequent collections in 1899 and 1900. The series was continued for the remaining groups of echinoderms in 10 volumes. While Thurston (1887-1895) of the Madras Government Museum gave and account of the echonoderms and their habitats in the Gulf of Mannar, Bell (1887-1889) reported on the earlier collections of the Investigator as well of those of the Madras Museum.
ii) 1901-1947
During this period, echinoderm material arising out of the Challenger, Valdivia and John M""ray expeditions from the Indian region were the additions to that of the Investigator. Further, Bengal Fisheries Trawler Golden Crown also made some echinodenn collections along the coasts ofOrissa and West Bengal during her cruises. In addition, scientists from educational and research institutions also contributed to our knowledge of Indian echinoderms. As a result, a number of monographic accounts and check-lists giving an almost complete taxonomic account of Indian echinodenns appeared during the period.
Alcock (1902) gave some general observations on the echinoderms encountered during the cruises of the Investigator. Monographic accounts on the different groups have been brought out by several workers on the material of Investigator, l'aldivia, Challenger, John Mu"ay and Siboga.
A.H. Clark (1902-1932) reported the Crinoidea of the Investigator's collections. Subsequent collections of Opbiuroidea by the Investigator and oth~r Indian material were studied by Koehler (1904, 1907, 1910). Complete accounts on the shallow-water and deep-sea Asteroidea were given by Koehler (1909, 1910). Later Koehler (1914, 1922, 1927) reported the'Echinoidea in three volumes. The monographic account on Holothuroidea was completed by Koehler and Yaney (1904¬1910). In addition, Bomford (1913) and Setna (1930) gave notes on some ophiuroids of the Indian Museum. Whil~ Jenkins (1922) made some observations in the shallow waters aboard the Golden Crown, and the echinoderms of the Gangetic delta were reported by Annandale (1922).
The echinoderms of Minicoy Island in the Lakshadweep collected during Gardiner's expedition to the Maldive and Laccadive Archipelagoes, were studied by Bell (1902). Unfortunately many of his identifications had to be corrected by later workers. Doederlein (1906) reported a new deep-sea echinoid off Nicobar Islands from the Challenger's collection. The monographic and revisionary accounts of Koehler (1904, 1905), Fisher (1911-1930), Doederlein (1915-1930), A.H. Clark (1915-1967), H.L. Clark (1921-1935), Mortensen (1928-1951), Hertz (1930) and John (1948), on the material collected during the Vaidivia, Siboga, Philippine and South Pacific expeditions as well as other material included severnl Indian species.
The echinoderms of Krusadai Island in the Gulf of Mannar and of the Madras beach were documented by Gravely (1927, 1941). There were also a few more reports of new species by Devanesan (1932), Mortensen (1936, 1939) and Nair (1944).
A good number of fossil echinoderms of South India, Khasi Hills, Bagh Beds. Rajasthan etc. were reported by Das Gupta (1921), Splenjer (1923), Rao (1927, 1929), Gee (1931), Chiplonkar (1937, 1939), West (1949) and Barooah (1946).
Studies on ecobiological aspects of echinoderms were also initiated during this period. Aiyar (1936) studied the development of the sea-urchin Salmaeis bieolor. Aiyar's (1938) continued studies resulted in a memoir on Salmaeis, the only one of its kind on Indian echinoderms till recent times. Earlier Aiyar and Menon (1934) studied the spicules of two sea-urchins, Salmacis hieolor and Stomopneustes variolaris. Symbiotic associations of various organisms with echinoderms were reported by Chopra (1931), Mukerji (1932) and Varadarajan (1939) while the parasitic gastropods were dealt with by Koehler and Vaney (1903, 1912, 1925). The occurrence of echinoderm larvae in the plankton off Madras coast was reported by K.S. Menon (1931) and off Trivandrum by M.A.S. Menon (1945).
iii) 1948-1990
Since the publication of the last volume of Echinodermata of the Indian Museum (No. X) by Koehler (1927) and subsequent notes on some ophiuroids by SeUla (1930) and a report on the associates by Mukherji (1932), the studies on the Indian Echinodermate at the Zoological Survey of India had come to a stand still until seventies when the studies were again started intensively.
However, with more and more Universities and research Institutions recognising the importance of echinoderms in various fields, a large number of works covering a wide variety of aspects of echinoderms appeared during this period. In the field of taxonomy emphasis has been on consolidating and updating the knowledge of regional fauna and revisionary studies in addition to reports of new records and new taxa. On the ecobiology front, the attention has been on the reproductive and biochemical aspects and the beche-de-mer resources. There have also been reports on the ecology zoogeography, symbiosis, development, toxicity etc.
Madsen (1951) included in his account, current status and detailed distribution of many deep-sea asteroids of the Indian region collected by the R.I.M.S. Investigator. James (1969) catalogued several echinoderms from various Indian localities and elsewhere, present in the reference collections of the Central Marine Fisheries Research Institute and James and Lal Mohan (1969) compiled an exhaustive bibliography on the echinoderms of the Indian Ocean. Clark and Rowe (1971) in their Monograph included all the shallow-water echinoderms of Indo-West Pacific region with keys for their identification, detailed distribution and a nearly complete bibliography. Important notes were also given by A.M. Clark, (1953, 1967, 1968,.1970), James (1971, 1987), Soota and Sastry (1979) etc;
While Guideon et ale (1957) mentioned some echinoderms from the Gulf of Kutch with incomplete identity, only the holothurians were studied by Gopalakrishnan (1969). Sane and Chhapgar (1962) reported 16 species of echinoderms. from Bombay of which four have been identified only up to genus. PatH's (1953) report contains only some common forms ~ith incomplete identification, from Karwar coast. Parulekar (1981) reported the echinoderms frQm Malvan. Whole studying the bottom fauna off Travancore coast, Kurian (1953) encountered four species of echinoderms. Several shallow-water species have been reported from Minicoy by Bell (1902) while Nagabhushanam and Rao (1972) listed a few more species which require conrmnation. Sivadas (1977) and Murty et ale (1979) reported the crown-of-thorns starfish, Acanthaster planei from the Lakshadweep. A thorough study of the echinoderm fauna of the Lakshdweep was made by James (1989) and further updated by Sastry (in press) Mukhopadhyay and Samanta (1983) and Mukhopadhyay (in press). .
The fauna of Gulf of Mannar has been well known. Chacko (1956), and Chacko et ale (1965) listed the fauna. James (1985) gave an updated list of echinoderms of the Gulf of Mannar. Mukhopadhyay (1988) studied the holothurian fauna of the area. The echonoderms in the Madras Government Museum collected chiefly from Tamilnadu coast were repOrted by Satyamurty (1976). Some echinoderms of the Kakinada Bay and of Oriss~ coast were listed respectively by Raclhakrishna and Ganapati (1969) and Nagabhushanam and Rao (1969). The echinoderm fauna of the state of West Bengal and of the Hughli-Matla estuary were studied by Sastry (in press) and Mukhopadhyay (in press).
From time to time, James of the Central Marine Fisheries Research Insittute has been reponing on the Indian echinoderms, chiefly from Andaman and Nicobar Islands. James (1983) compiled a list of echinoderms reported from these islands. Julka and Sumita Das (1977), Sastry (1977) and Soota et ale (1983) respectively reported some asteroids, echinoids and holothurians from Andaman and Nicobar Islands.
Daniel and Haldar (1974) reviewed the holothurians of the Indian Ocean with special reference to their distribution. James (1980, 1987) reviewed the studies on the echinoderms of the Indian Ocean and of India respectively and in the latter gave the correct identity of species reported by earlier workers such as Bell, Thurston, Gravely etc.(Loc cit)
There have been several studies on the reproductive behaviour, biochemical changes and early development of some echinoderms. Important among them are those of Shetty (1960), Giese et ale (1964), Rao (1965, 1968), Rahman (1966, 1968), Krishnaswamy and Krishnan (1967), Krishnan (1967-1970), James (1973) and Krishnan and Mary Bai (1977). Several associates of various Indian echinoderms were reported by Ganapati and Sastry (1972), Rao and Sowbhagyavati (1972), Jones and James (1970), Sastry (1977, 1981), Daniel and Krishnan (1978) etc. The beehe-de-mer resources, collection, processing, food value, marketing etc. have been dealt with by Durairaj (1982), Jacob (1973), James (1989) and Lal Mohan (1989). James (1983) gave an account of the sea-urchin and sea-cucumber resources with particular reference to Andaman and Nicobar Islands, while Reuben el ale (1987) studied the sea-urchin resources of Waltair coast
The occurrence of echinodenn larvae in the plankton has been studied.by George (1953), Prasad (1954) and Meenakshi-kunjamma and Gopalakr:ishnan (1977).
The fossil echinoderms from Rajasthan have been reported by several workers notably Sahni and Bhatnagar (1955, 1958), Hoffman (1963), Pascoe (1963), Gupta et ale (1967) and Gupta (1972). In addition, there have been a few more reports on unidentified fossil echinodenns.
Studies from Different Environs
Echinoderms as a whole inhabit all the possible environs of the marine ecosystem including corals, rocks, shingle beds, sandy shores, muddy bottoms, algal beds, mangroves, estuaries etc. and from the intertidal regions to abyssal depths. There are also some boring, fouling, epizoic and planktonic forms.
Most of the earlier works are of taxonomic and faunistic nature and contain only casual references to the nature of the habitat. Later works contained some information on the general nature of the environment from where the fauna have been collected. There have been only very few works pertaining to the echinoderm fauna with emphasis on the habitat. Rao (1968-1980) and Rao and Misra (1983) studied the taxonomy ecology and zoogeography of the interstitial holothurians. Sastry (1985) compiled a list of echinoderms of the Indian estuaries. Das (1985) reported a starfish from an estuarine region in the Andaman and Nicobar Islands. Some echinoderms from the mangrove habitats of the Andaman and Nicobar Islands have been reported by Das and Dev Roy (1989). Coral inhabiting echinoderms, particularly the crown-of-thorns starfish, Aeanthaster planei of the Andaman and Nicobar Islands were studied by Mustafa et ale (1989), and Pillai et ale (1989). Rao and Dev Roy (1985) mentioned some echinoderms of cor~ habitats of the same areas. The account of Tikader et ale (1986) contains references to the habitats of some echinoderms of the ADdaman and Nicobar Islands. A detailed account on the different habitats inhabited by several echinoderms of Indian region is however, that of James (1987)~ He also reported Several echinoderms encountered as borers, foulers and epizoans (James, 1988).
The collections of R.I.M.S. Investigator included material from both the shallow-water and deep-sea environs. However, later studies in India pertained only to the shallow-water habitats because of their easy accessibility and lack of organized explorations of the deep water elements for taxonomic purposes. With the result, our knowledge of the deep water echinoderm fauna of the Indian region has been confined to what the earlier workers chiefly on the material collected by Investigator, reported six decades,back. The knowledge on the shallo,,<-water fauna. is being updated and consolidated from time to time by James (1969-1989), Sastry (1977-1987 and in preSs),-Soota and Sastry (1979), Soota et ale (1983), Mary Bai and Ramanathan (1977), Mukhopadhyay and Samantha (1983), Mukhopadhyay (1988 and in press) etc. Recently a thorough taxonomic study of the echinoderm fauna of the Lakshadweep, West Bengal, Hughli-Matla estuary and holothurianS of Gulf of Mannar has been made in the above mentioned works. James (1983, 1985) compiled a list of echinoderms known from the Gulf of Mannar and Andaman and Nicobar islands. Howeva:", th~ have been only partial or scattered reports on the echinodenn fauna of other regions such as GuIt of Kutch, Maharastra, Kama taka, Kerala, Andhra Pradesh and Orissa. There is also dearth of information on the ecob~ological aspects of echinoderms, no specieS baving been studies thoroughly. Available information on the regional fauna is summarized below.
Of the six extant classes of Echinodermata, the class Concentricycloidea is not so far known to be represented in the Indian waters. The other five classes have been reported by a fair number of species. The majority of echinoderms were known by the year 1927 through the extensive collections made by workers on board the R.I.M.S.lnvestigator. Subsequently, there have been some additions to the deep water element by the Challenger. Valdivia and John Murray Expeditions. The shallow-water fauna has been under a thorough region-wise and group-wise study by Dr. D.B. James of Central Marine Fisheries Research Institute and scientists at the Zoological Survey of India. Thus, several additions and revisions of the Indian echinodenns have been made. The following is a compilation of the Indian species based on published as well as unpublished information. The numbers are approximate since delineation of strictly Indian territory is not always possible and is also not meaningful in respect of marine fauna.
Class Number of Indian representatives Families Genera Species
The deep water component varies roughly from 35 to 65 per ceJlt in different groups. Most of the shallow-water species inhabit hard coral and rocky habitats. As the eehinodenns are in general less tolerant to wide fluctuations in salinity for prolonged periods, only a few species occur particularly during summer months of relatively higher salinity, in or near the estuaries.
Classified Treatment
Most of the earlier studies particularly of Wood-Mason, Alcock, Bell and some of the subsequent works of Clark and Rowe (1971), James (1969) etc. deal with more than one classof Echinodennata and are of purely taxonomic character. These have already been dealt with under the Historical Resume. Only the studies pertaining to other aspects of echinoderms are being mentioned here.
Class Crinoidea
Other than taxonomy, only biological associations of crinoids have been reported. Jones and Sankarankutty (1960) reported a pea-crab from Lamprometra, while Nayar and Mahadevan (1967) reported occurrence of crinoids on a gorgonid, both from the Tamil Nadu coast. From Waltair coast of Andhra Pradesh, Rao and Sowbhagyavati (1972) enc9untered several groups of animals particularly myzostomes, crustanceans, polychaetes and molluscs associated with crinoids. Sastry (1981) reported two species of shrimps from the crinoids of Bay of Bengal. James (1987) made some observations on the ecology of some crinoids. James (1988) reported eight species of crinoids encountered as foulers two species of pohiuroids as epizoic on crinoids.
Class Asteroidea
The reproductive and related aspects of Pentaeeraster regulus were studied by Rahman (1966, 1968) and Rao (1965, 1968). The early development of Asterina burtoni was studied by James (1974). Mustafa et ale (1989), Pillai et ale (1989) and Wood (1989) at Andamans and Sivadas (1977) and Murty et ale (1979) at Lakshdweep made some observations on coral habitats with particular reference to the presence of the crown-of-thorns starfish, Aeanthaster planei. Das (1985), Sastry (1985) and Das and Dev Roy (1989) mentioned the star fish species encountered in the estuarine and mangrove habitats. Various symbionts associated with asteroids were reported by Mukerji (1932), Varadarajan (1939), Rao (1962, 1964) and Jones (1965). Some parasitic gastropods from asteoids were mentioned by Koehler (1909, 1910). James (1988) encountered seven species of asteroids as foulers.
Class Ophiuroidea
Panikkar and Prasad (1952) reported the occurrence of Ophioenemis marmorata along with the coelenterate Rhopilenema hispidum at Mandapam. Ophiomaza eaeaotielJ is a well known epizoan or even parasitic, on crinoids and sometimes on gorgonids. James (1988) reported the ophiuroids encountered as epizoans and foulers. The swarming behaviour of Ophioenemis marmorata at Ennur backwaters was reported by Evangeline (1966).
Class Echinoidea
Alcock (1902) mentioned some habits of Eehinostrephus molaris at Lakshadweep. The spicules of Salmacis bieolor and Stomopneustes variolaris were studied by Aiyar and Menon (1934) and the development of salmaeis bieolor by Aiyar (1936). The memoir on Salmaeis by Aiyar (1938) gives a brief account of echinoid classification, common Indian echinoids and also several aspects of echinoid biology with emphasis on Salmaeis. Shetty (1960) studied the early development of Stomopneustes variolaris, while the reproductive and biochemical changes and other related aspects were studied by Giese el ale (1964). The effect of starvation on the nutrient reserves in the test, gut and gonads of Salmaei..v virgulata were reported by Krishnan and Mary Bai (1977). The sea-urchin resources were dealt with by James (1983) and Reuben et ale (l987). Three species of echinoids which bore into rocks and dead corals and Salmaeis virgulata encountered as a fouler were reported by James (1988).
Ganapati and Sastry (1972) reported an alpheid shrimp, barnacle, stiliferid gastropod and a gobiid fIsh associated with Stomopneusles variolaris at Visakhapatnam coast. Sastry (1977, 1979) encountered two species of shrimps and a crab associated with sea-urchins of Nicobar Islands. Daniel and Krishnan (1978) reported their observations on the association of the carb Zebrida adamsii with Salmaeis virgulata. Koehler (op. cit) and Koehler Vaney (1912, 1925) described the pamsitic gastropods of sea-urchins.
Krishnan (1967-1970) and Krishnaswamy and Kris~nan (1967). The monograph of Mary Bai (1980) on H. scabra includes observations on anatomy and regeneration also. Successful induced breeding and development under captivity is the recent interesting contribution by James et ale (1988). Biotoxicity and bioactivity of holothurians were studied by Rao et ale (1985, 1987). James (1986) suggested the use of holothurian toxin for eradication of unwanted species in the fIsh farms. Various associations with holothurians were reported by Mukerji (1932), Chopra (1931), Ganapati and Radhakrishna (1963), Nayar and Mahadevan (1965), Jones and James (1970) Jones and Kumaran (1980) and James (1987). The taxonomy and zoogeography of interstitial holothurians were studied by Rao (1968-1983). Since the earlier reports on the beche-de-mer industry by Collier (1930) and Hornell (1917) there have been mentions about it in many works.
The more recent.ones by Durairaj (1982), Durairaj et ale (1984), Lal Mohan et ale (1987), James (1983, 1986, 1987, 1989) and Narasimham et ale (1984) dealt specifIcally and in detail with various aspects of the industry such as, resources, collection, processing, food value, quality control, marketing, export, conservation etc.
In addition, several papers dealing with reproductive cycles, digestive enzymes, effect of low salinity, and a polychaete associate of Stomopneustes variolaris, ecology, zoogeography, echinoderm associates several aspects of beche-de-mer industry etc were presented by James, Sastry and others at various symposia and work-shops.
Current Studies
At Zoological Survey of India, mainly taxonomic studies are at present undertaken with emphasis on state-wise faunal accounts. The projects on the echinoderm fauna of the Lakshadweep West Bengal and Hughli-Matla Estuary have been completed. The current projects are on the echinoderm fauna of Gujarat coast and ecology and population dynamics of Aeanthaster planei at Andaman Islands.
At the Central Marine Fisheries Research Institute, Cochin and its various research stations, James and others are engaged on the taxonomy, zoogeography, ecology and various aspects of sea¬urchin and sea-cucumber fishery, resources, and culture.
At other Research Institutes and Universities work on ecobiological aspects of echinodenns is being undertaken.
Outside India, several scientists, particularly from United States of America, United Kingdom, France, Denmark, Belgium, China, Australia, Japan, and New Zealand are engaged in.revisionary studies, ecobiological and physiological aspects, pollution monitoring, evolution and classification etc.
Expertise India
In ZSI
D. R. K. Sastry &S. K. Mukhopadhyay, ZSI, 27 Jawaharlal Nehru Road, Calcutta -700 016
M. Mary Bai, ZSI, Southern Regional Station, 100 Santhome High Road, Madms -600 028
K. Venkataraman &P. T Rajan, ZSI, Andaman and Nicobar Regional Station, Middle Point. Port Blair -744 101
Elsewhere
D. B. James, Tuticorin Research Centre, C.M.F.R.I. Tuticorin -628 001
S. Reuben, Waltair Research Centre C.M.F.R.I. Visakhapatnam -530 003
Echinodermata 569
S. Krishnan, Department of Zoology, Bangalore University, Bangalore -560 056
V. Jayasree, National Institute of Oceanography, Goa -403 004
Abroad
A. N. Baker &H. E. S. Clark, National Museum of New Zealand, Private Bag, Wellington, New Zealand.
A. M. Clark, British Museum (Natural History) Cromwell Road, London, SW7 5BD, U.K.
T. E. Ebert, Department of Biology, San Diego State University, San Diego, California,
3.Guille, Museum National d'Histoire Naturelle, Laboratoire de Biologie des Invertebres Marins, 55 Rue de Buffon, 75005 Paris, France. 4. 5.Jangoux, Laboratoire de Zoologie, Universite Libre de Bruxelles, 1050 Bruxelles, Belgium. 6. 7.M. Lawrence, Department of Biology, University of South Florida, Tampa, Florida 33620, 8. 9.Yulin Liao, Institute of Oceanology, 7 -Nan-Hai Road, Tsingtao, China. 10. 11.J. Madsen, Zoological Museum, Universitetsparken, 15, DK-2100 Copenhagen, Denmark. 12. 13.M. Marsh, Department of Marine Invertebrate Zoology, Western Australian Museum, Francis Street, Perth W.A. 6000, Australia. 14. 15.L. Pawson, Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington D.C. 20560, U.S.A. 16. 17.W. E. Rowe, Australian Museum, 6-8 College Street, . Sydney, New South Wales 2000, Australia 18.
Selected Rererences
Echinodermata of the Indian Museum, Parts I -X (1899-1927), Calcutta. Reports on the echinoderm material collected by the R.I.M.S./nvestigator, by A. H. Clark, R. Koehler &C. Yaney. A Monograph of the existing Crinoidea, Vol. I The comatulids. Parts 1 to 4c by A. H. Clark (1915-1950) and part 5 by A. H. Clark &A. M. Clark (1967). Bull U.S. natn. Mus., 82" Clark, A. M. &Rowe, F.W.E (1971) Monograph ofshallow-water Indo-west Pacific echinoderms.
238 pp. BriL Mus. (N.H;): London. Clark, H. L. 1915. Catalogue of recent ophiurans. Mem. Mus. compo Zool. Harv., 2S : 165-376. Fisher, W. K. 1911-1930. Asteroidea of the North Pacific and adjacent waters. Bull. U~S. naln.
Mus., 76 (1-3). Hyman, L. H. 1955. The Invertebrates, IV Echinodermata. 763 pp. McGraw Hill, N.Y. James, D. B. 1981. Research on Indian echinoderms-a review, J. mar. biol.Ass.India, 25:91¬ Jangoux, M. &Lawrence, J. M. (Eds) Echinoderm studies A. Baltema, Rotterdam. So far three volumes of the continuing series have been published in 1983, 1981 and 1989 respectively.
Mortensen, Th. 1928-1951.ltlonograph ofEchinoidea, Vol. I-V. Copenhagen.
