Polychaeta: India
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Polychaeta
Introduction
Polychaetes are a group of worms well known since the early periods of man's interest to study palural history. Majority of these worms are benthic, only a few are pelagic. Benthic polychaetes are most commonly encountered on sandy or muddy bottoms extending from the sea shore to the greatest depths of the hadal zone. Basically being inhabitants of marine environments, the polychaetes are also common in the estuaries enjoying an everchanging brackish water environment, and a few tolerant species may even extend up to the freshwater zone.
Polychaete worms, commonly known as bristle worms, belong to the Class Polychaeta under the Phylum Annelida, with more than 8,000 global species, including approximately 400 species from India. The body from 'of this group of worms varies, depending on whether they are free moving, sedentary or pelagic. This is such a varied class that almost any modification could be found, if searched for. To mention some of the special adaptations, of this group are : nest building with sea grass, tube building with various material (hard calcium tubes, leathery. mucous tubes, delicate sand tubes), fitter feeding nests and strong jaws to catch prey. Polychaetes are traditionally separated into two large orders, Errantia and Sedentaria, on the basis of development of the anterior end and the life habits of the species. Several attempts were made to subdivide the polychaetes and the various systems proposed differed considerably in structure and in the number of families incorporated. Fauchald (1977) proposed a scheme of classification based on phylogenetic relationships and recognised 17 orders and seven suborders to include 71 families.
Major anatomical as well as morphological features were used to define the orders. But the system is still incomplete, because Fauchald could not accotnmodate 5 families in any of the established orders, and another 5 families in suborder. In spite of the great volume of literature on the polychaete taxonomy there is no general agreement on the problems of grouping families into orders.
Among all the marine benthic organisms, polychaetes constitute the most important component of the macro-invertebrates. The extensive use of polychaetaus annelids as indicators of various degrees of marine pollution is a recent development, though Wilheloni (1916) made the fust reference to the polychaete, Capitella capitata (Fabricius), as an indicator species. The variety and abundance of species present can often be used as an indication of the cleanliness of the environment in which they live (Jones 1969, Moore 1972).
Historical Resume
i)Pre-1900
Previous to the year 1900 practically nothing was known concerning the polychaetes of India, apart from the report of a tubicolous polychaete (unidentified) on the beach of Kelvi, Mahim, 80 km. north of Bombay, by Keswal (1892). The earliest record of polychaetes from India dates back to 1908 when Stephenson described a capitcllid worm, Malia bengalensis wrongly designating it as an oligochaete worm, from Port Canning, Gangetic delta. But later, in 1910, he himself recognised that as a polychaete. From the same locality, Willey (1908) described a spionid worm, Spio bengalensis. However, the first comprehensive account of the brackishwater polychaetes of India was published by Southern (1921).
In all he recorded 30 species of polychaetes from the Gangetic delta, Chilka Lake and Cochin backwater. A total of three new genera and 27 new species were described from the above mentioned areas. Gravely (1927, 1930) documented the polychaete fauna of Krusadi Island in the Gulf of Mannar. Subsequently, a series of papers were published on the taxonomy, anatomy, development and breeding habits of brackish water polychaetes (Aiyar 1931, 1933b, 1933c, 1939, Aiyar and Panikkar 1937). Polychaetes of interstitial habitats had received considerable attention (Aiyar and Alikunhi 1940, 1943, Alikunhi 1941a, 1941b, 1942, 1943, 1947). Panikkar and Aiyar (1937) gave an account of the brackishwater fauna of Madras, where 19 species of polychaetes were included.
ii) 1901-1947 During this period the collections of th Zoological Survey of India and of the Indian Museum, Calcutta, were extensively studied by Fauvel (1928, 1929, 1930, 1932, 1940), which included polychaetes not only from the coasts of India, but also from those of the neighbouring countries. Three hundred species were recorded in Fauvel's report (1932). Subsequently, Krishnan (1936) described the development of a brackish water polychaete Diopatra Variabilis and later in 1946 (unpublished thesis) made an extensive study on the polychaetes from Madras. Ranganathan (1943) reviewed the mode of breeding and development in brackish and freshwater polychaetes. While studying the growth and breeding of certain sedentary organisms in the Madras harbour, Paul (1942) included certain polychaete species of the area.
The circulatory system ofNereis cultrifera was described by Karandikar &Thakur (1946).
The archiannelids belonging to the genera Polygordiust Protodritus and Saccocirrus were taxonomically investigated by Aiyar (1930). Aiyar and Alikunli (1940, 1944), Alikunli (1943, 1946, 1948).
i)1948-1990
During the period under consideration it has been observed that gradual emphasis was paid towards the investigation of the polychaetous worms from diversified habitats of different areas of India. But taxonomic literature on this group of annelids from India is poor. However, recent ecological and distributional studies relating to the benthos of the different marine and brackishwater areas of India, indicate that the Polychaeta is one of the dominant and diversified groups of organisms inhabiting particular habitat.
The most important work on the taxonomy of polychaetes pertaini11g to Indian water is that of Fauvel (1953). In his monumental work, Fauvel (1953) reviewed all the earlier works of Polychaeta from India and adjacent areas wherein he recorded 450 species of which 283 belong to the Indian territory, including 47 brackish water forms. He, however, believed that this number represented only about one half of the expected total.Other significant contributions are those of Hartman (1975 &1976) who studied the polychaetes collected dwing the International Indian ocean Expeditions (1963-64), and prepared a catalogue and a bibliography of the species from India.
Most of the other investigations dealing with polychaetes from coastal and brackish water habitats are regional in nature. The polychaete fauna of Digha beach in West Bengal was dealt with by Rao &Misra (1988). Misra, Chakraborty and Soo13 (1987) prepared a list of species and studied the polychaete fauna of Orissa coast. Earlier works dealing with polychaetes from Orissa are those of Nagabhushanam Rao (1969), Soota &Rao (1977), Ganapati &Lakshman Rao (1962) and Sarma (1977), who included polychaetes in their generalised ecological investigations in Visakhapatnam coast. Rao &Soota (1977) prepared a short list of species from Tamil Nadu coast. Srikrishnadhas, Ramamoorthi & Balasubramanyan (1987) reported the polychaetes from Porto Novo waters. The polychaetes of the southeast coast of India in general and of the Gulf of MaQnar in particular, received attention of several workers (Bause, 1959; Ghosh, 1963; Rangarajan, 1963a, 1963, 1964, Rangarajan &Mahadevan, 1962 and Rajarnjan &Sankarankutty1 1962)."
While investigating the benthos of the Bay of Bengal, Ansari, Harkantra &Nair (1977) reported polychaetes as one of the major constituents of the fauna. Th.e polychaetes of Andaman and Nicobar Islands were investigated and the results published in a series of papers (Tampi &Rangarajan, 1963 &1964; Daniel &Ghosh, 1964; Soo13 &Rao;'1977; Rao &Soota, 1977; Soota, Misra &Chakraborty, 1980; "and Parulekar &Ansari, 1981). The ecology of the intertidal fauna of the sandy beaches of southwest CQast of India was investigated by Trevallion, Ansell and Sivadas (1970) and Philip (1972). The taxonomy of the polychaete fauna of Ratnagiri, south of Bombay, was dealt with by Day (1973), Pettibone (1977), Gaikwad &Ranade (1979), Parale &Gaikwad (1989) and Wadker &Gaikwar (1989). An account of the polychaetes of Bombay waters is available in Bhatt &Bal (1964).
The occurrence of Arenicola in Indian waters was first reported by Ranade (1952) and subsequently described by Kewalramani, Wagh &Ranade (1959). The studies on the polychaete fauna of Maharashtra and Goa by Parulekar (1971) and of Malvan by Parulekar (1981) deserve special mention. The marine fauna of Karwar coast and neighbouring Islands were investigated by Patil (1951). Attempt was made to investigate the polychaete fauna of the Gujarat coast by Dalal &Dubale (1975) and Dalal, Dubale &Shah (1978). Dalal (1982) made some ecological investigations on the polychaetes of Okhawandal region. More studies n the polychaetes of the coastal region of Gujarat are available in Rao &Soota (1981), Soota, Misra &Chakraborty (1981), and Misra &Chakraborty (1983).
Works on the brackish water polychaete fauna of India has been systematically taken up in recent years. But such works throw little light on the distributional patterns of these worms. This is largely due to the fact that many of these areas were not adequately surveyed and studied. Hitherto, a limited number of brackish water areas viz. HugH-MatIa, Go.davari, Vellar, Chilka and Pulicat on the east coast and Mandovi -Zuary and Vern banad on the west coast of India, have fairly been surveyed. A total of 171 species spreading over 97 genera and 38 families have so far been reported from the brackish water bodies of India. Informations about the polychaete fauna of Hugli -Matla estuarine complex is available from Southern (1921), Fauvel (1932) and Misra et ale (1984). Most of the recent ecological investigation in this estuarine complex (Datta &Sarangi, 1980; Bhuniya &Choudhury, 1981; Nandi &Choudhury, 1983; Choudhury et al., 1984a, b) indicate, that this group of worms is one of the most important components of the benthic fauna.
While reporting on the polychaete fauna of Orissa, Misra et ale (1988) observed that 46 species were available in the brackish water habitats of Orissa. The polychaetes of Chilka Lake were studied by Southern (1921), Rajan (1965) and Patnaik (1972); of Mahanadi estuary by Julka &Rao (1976); of Baitarani and Burhabalang estuary by Soota &Rao (1977) and Rao (1981).
Detailed benthic faunal investigations in the Gautami -Godavari estuary were conducted by Radhakrishna (1963) and Radhakrishna & Ganapati (1968). An eco-biological investigation of these worms from the Vashista -Godavari estuary was undertaken by Srinivasa Rao &Rama Sanna (1978a &b, 1979, 1980, 1981, 1983a &b). Ganapati &Raman (1976) recorded Capitella capitata as an indicator of pollution in the Vishakhapablam harbour. While surveying the effects of pollution on the eco-biology of benthic organisms in Vishakhapatnam Harbour, Raman &Ganapati (198,3) reported that polychaetes were not only the most div.erse, but in terms of population density, they often formed an incredibly high percentage of organisms collected at any station.
The polychaetes of Adyar estuary and other brackish-water bodies around Madras were dealt with by Panikkar &Aiyar (1937). Krishnamoorthy (1973) observed the distribution of six species ofpolychaetes in the Adyar estuary. While the lenthic fauna of ValIer estuary on the east coast of India has been thoroughly~investigated by Balasubrahmanyan (1960a &b, 1964), McIntyre (1968); Ajmal Khan et ale (1979), Srikrishnadhar et ale (1981) and Chandral et ale (1982). The polychaete fauna of the Pulicat Lake was merely listed by Chacko er ale (1953) and taxonomically investigated by Sunder Raj &Sanjeeva Raj (1987).
The occurrence ofpolychaetes in the Cochin Harbour area was fust reported by Chcriyan (1966) and subsequently investigated by Desai &Krishna Kutty (1967) and Gopalakrishna Pillai (Thesis, 1978).
The ecology of benthos in relation to salinity and substratum in the Mandovi estuary in Goa was studied by Parulakar &Dwivedi (975). Biomass and faunal composition of the Zuary estuary was studied by Parulekar et ale (1975). They found the polyhaline condition and sandy substratum accounted for high biomass, while higher population density was noted at euryhaline zone. Polychaetes were found to be the dominant group in silty bottoms wh.ile bivalves in the sandy bottoms. Parulekar et. ale (1980) prepared a list ofpolychaetes occurring in Mandovi-Cuinbarjua canal-zuary estuarine system. while studying the intertidal benthic community structure of sand¬dwelling macrofauna of an estuarine beach (Siridao) in Goa, Harakantra & Parulekar (1984, 1985) observed that the number of polychaete species was the highest, though quantitatively they formed the co-dominant group.
Polychaetes are also common in the intertidal habitats of the beaches along the Indian coast. Significant contribution on the intertidal polychaetes of India are those of Rao & Ganapati (1966, 1967, 1968), Rao (1969a, 1969b, 1970a, 1970b, 1972, 1975, 1978, 1980), Rao & Misra (1983a, 1983b, 1988) and Westheide &Rao (1977).
Apart from the larval and post-larval stages, some of the polychaete species are truly planktonic in nature. Chacko (1950) investigated the marine plankton in general f~om the waters around the Krusadai Island. Bal &Pradhan (1952) recorded the zooplankton in Bombay waters. Thomas (1963) dealt with the taxonomy of a palagic polychaete species of the genus Loandalia.. In a series of papers Peters (1967, 1973a, 1973b, 1974 & 1977) dealt with the taxonomy, distribution and abundance of pelagic polychaetes of Indian waters. Seasonal variation in the plankton of Porto¬Novo waters was studied by Krishnamoorthi &Daniel (1967). Ganapati &Radhakrishna (1958) studied the polychaete larvae in the plankton off WalUrir coast The ecology of polychaete larvae of Porto Novo waters was studied by Srikrishnadhas & Ramamoorthi (1982).
Several species of polychaetes live in class association with other invertebrates and often termed as commensals. Krishnamoorthi &Daniel (1950) described a rare case of commensalism between Amphinome aralifera, and Sankolli &Sheno (1965) described a case of commensalism between Loimia medusa and a porcellanid crab. Ganapati and Radhakrishnan (1962) reported a case of inquilimism between a hesionid worm and a holothurian species. Kirkegaard &Santhakumaran (1967) described a new species of cirraculid worm occurring in association with marine wood borer. Kumaraswamy Achari (1971) dealt with three species of sabellarid worms occurring in close association with sponges and corals. Rao &Sowbhagyavathi (1972) made detailed observation on the associates of crinoids at Waltair coast with special reference to Myzostomes.
Studies from Different Environs
Most of the species of polychaetous worms are basically inhabitants of marine habitats. However, these are also common in the brackishwater environment and only a few of them may extend up to the freshwater zone. The majority of the species are benthic, only a few are pelagic. Most of the benthic polychaetes prefer sandy or muddy substrata extending from the sea shore to the greatest depths of the hadal zone; some are found to be comfortable in the crevices of rocks or coral reefs. Availability of polychaetes in diverse ecological niches is due to their high degree of adaptibility to a wide range of environmental factors.
Fauvel provided a comprehensive account of the polychaetes of Indian waters and its adjacent areas. He has published a series of papers (vide Historical Resume) of which the 'Fauna of India: Annelida, Polychacla', appeared in 1953 is most significant. Hartman (1975, 1976) dealt with the polychaetes of the Indian ocean collected during the International Indian ocean Expedition (1963¬1964). However, Soulhern (1921) is the pioneer in providing a comprehensive account of the brackish water polychaetes of India. The studies relating to the marine and estuarine" benthic as well as pelagic forms arc dealt with separately in the Historical Resume. So far, only a limited number of bracksihwatcr bodies, viz., Hugli-MalIa, Godavari, Vellar, Chilka and Pulical on the east coast and Mandovi-Zuary and Vembenad on the west coast of India, have fairly been surveyed. India has a vast coastline of about 6000 km which has not been adequately surveyed for the collection and study of the polychaetous worms.
Estimation of Taxa
Several attempts were made to subdivided the polychaetes, and the various systems proposed differed considerably in structure and in the number of families incorporated. Hartman (1959) included 33 families of Errantia, 28 families of Sedantaria, 3 families of parasitic polychaetes and 3 families of aberrant groups in her system but did not group them into orders. Fauchald's (1977) scheme of classification includes 81 families of which 76 families are grouped under 17 different orders and 5 families are of uncertain affinities. In recent literature, polychaetes are treated under families without specifying any order.
The knowledge of the Indian polychaetes is far from complete and scattered in nature. Therefore, an accurate assessment of the fauna is very difficult to propose. Out of the 81 recognised families, nearly 950 genera and 8000 species of polychaeta, 61 families and more than 200 genera and 400 species are represented in Indian waters.
Most important work on the taxonomy of polychaetes pertaining to Indian waters are those of Fauvel (1932, 1953), •which include 283 species belonging to the Indian waters, of which 47 species were recorded from the brackish-water habitat. Taxonomic literature on the brackishwater• polychaete fauna of India is poor in comparison to that of its marine component. A .careful, review of literature reveals that 171 species of polychaetes under 38 families are recorded from the brackisliwater habitais of India.
Current Studies
In Zoological Survey of India taxonomy and distribution of polychaetes•of marine (Andamans &, Gujarat) and brackish-water habitats (Chuka Lake and Hugli-Matla estuary) of India are cwrenlly under study.
Outside ZSI, no serious attempt has been made for taxonomic investigation on this group of annelid. However, the eco-biological investigations are done in ; Marine Science Department, Calcutta University; Department of Zoology, Andhra University, Waltair; Centre for Advance studies ~n Marine Biology, Porto Novo; National Institute of Oceanography, Goa; Department of Fish Hydrography, College of Fisheries, Ratnagiri.
Expertise India
In ZSI
A. Misra and R. K. Chakraborty both of Zoological Survey of India, Calcutta. C. A. N. Rao, Zoological Survey of India. Berhampur.
Elsewhere
U. D. Gaikwad, Associate Professor, Dept. of Fish Hydrography, College of Fisheries, Ratnagiri -415612 [Taxonomy]
p. J. Sanjeeva Raj, Dept. of Zoology, Madras Christian Collge, Tambaram~ Madras 600 059 [Taxonomy]
A. V. Raman, Dept. of Zoology, Andhra University, Waltair. [Eco-biology]
D. Srinivasa Rao, Noble College, Machilipatnam-521001 [Taxonomy &Ecology]
A. H. Parulekar, National Institute of Oceanography, Dona Paula, Goa 403 004. [Ecology &Population Biology]
B. Srikrishnadhar, Fisheries College, Tuticorin, Tamil Nadu [Ecology]
A. Chaudhury, Dept. of Marine Science, Calcutta University, Calcutta 19 [Ecology & Population Biology]
ABROAD
P. A. Hutchings, Dept of Marine invertebrates, Australian Museum, P.O. Box. A285 Sydney South, Australia 2000.
J. D. Kudenov, Marine Pollution Studies Group, Fisheries and Wildlife •Division, 605 Flinders Sf:reet Extension, Melbourne, Victoria 3000, Australia.
M.. Imajima, National Sciences Museum, 3-23-1 Hyakunin -cho, SJ'linjuku -Ku, Tokyo 169, Japan.
W. Westheide, Zoologisches Institut der Universitat, D-34 Gottingen, Germany.
Gesa Hartmann -Schroder, Zoologisches Institute und Zoologiscbes Museum der Universitat, 2 Hamburg, 13 Von-Melle-Park-l0, Germany.
M. H. Pettibone, National Museum of Natural History, Smithsonian Institution, Washington, 20560.
Fanchald, National Museum of Natural History, Smithsonian Institution, Washington, 20560.
Banse, School of Oceanography, W. B ... 10, Seattle, W.A. 98195, U.S.A.
D. George, Dept. of Zoology, British Museum (Nat. Hist.), London.
H. A. ten Hove, Institut Voor Taxonomische Zoologie, Zoologisch Museum, Pos~us 4766¬1009 AT, Asmterdam, Nederland.
Selected References
Fauchald, K. 1977. The Polychaete worms : Definitions and keys to the orders, Families and Genera. Nat. Hist. Mus., Los Angeles Country. Sci. Sr., 28 : 1-88. Fauvel, P. 1953. The fauna of India including Pakistan, Ceylon, Burma and Malay. Annelida, Polychaeta, XII 507 pp.
Hartman, O. 1974. Polyc!taetous annelids of the Indian Ocean including an account of species collected by members of the international Indian ocean Expeditions, 1963-64 and a catalogue and bibliography of the species from India. Pt. 1. J. mar. bio•. Ass. India, 16(1) : 191-252; Pt. 2. J. mar. bioi. Ass. India, 16(2) : 609-644.
Southern, R. 1921. Polychaeta of the Chilka Lake and also of fresh and brackish waters in other parts of India. Mem. Indian Mus., 5 : 563-659.
