Marine Porifera: India

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This is an extract from
ANIMAL RESOURCES OF INDIA:
Protozoa to Mammalia
State of the Art.
Zoological Survey of India, 1991.
By Professor Mohammad Shamim Jairajpuri
Director, Zoological Survey of India
and his team of devoted scientists.
The said book is an enlarged, updated version of
The State of Art Report: Zoology
Edited by Dr. T. N. Ananthakrishnan,
Director, Zoological Survey of India in 1980.

Note: This article is likely to have several spelling mistakes that occurred during scanning. If these errors are reported as messages to the Facebook page, Indpaedia.com your help will be gratefully acknowledged.

Contents

Marine Porifera

Introduction

The period between 1765 and 1892 marked what could be termed the glorious era in the history of spongology and this was largely due to the pioneering work of scientists like Carl Linnaeus, George Cuvier, Jean Lamarch, J.E. Gray, R.E. Grant, G.D. Nardo, J.S~ Bowerbank, H.J. Carter, N. Liebcrkuhn, F.E. Schulze, E.O. Schmidt, G.C.J. Vosmacr, E.H.P.A. Haeckel, A. Hyatt, C. Keller, W. J. Sollas, S.D. Ridley, R. von Lendenfcld, N. Polejaeff, A. Dendy and E. Topsent in systematising the various groups of sponges, after studies on their physiology and the phylogeny. The sponges were till then considered to be plants and it was Ellis (1765) who fust demonstrated the animal nature of sponges by observing the water currents produced by the oscula and the movements of the general body surface. As a result, scier:Itists like Linnaeus, Lamarck and euvier grouped them together with the coelenterates, until Blainville (1816) placed them in a special group, Spongiaria. Grant (1836), who studied the morphology and physiology of this group, established the name Porifera. Later workers like Huxley (1875) and Sollas (1884) argued for the separation of the sponges from other multicellular forms (metazoa). According to modem zoologists, this group constitutes an isolated branch of metazoa called Parazoa, after Sollas.

Four different periods can be broadly demarcated in the history of spongology. A general interest which found expression in an overall study of the local fauna forms the central theme of the first period. This got amplified in the second on account of the facilities provided by many countries venturing for extensive voyages and expeditions. The material thus collected from far off places resulted in the monographic treatment of the families and the genera. The impact of the theory of evolution reached its zenith during this period. From the study of the major taxa and their evolution the attention then got diverted to the study of intraspecific variations, and this marks the third period. The fourth period, which includes the more recent work on sponges, belongs to the present century which has come to be characterised by a 'continuous refmement df the methods and concepts developed in the 19th century' (Mayr et al. 1953). The work of Levi (1956) and of Tuzet (1948) on the embryology and systematics, of Bergmann (1949) on sterols, of Harbnan (1958) on systematics,-ecology and life history of Porifera are examples, to cite a few.

Historical Resume

Spongology of the Indian Seas up to 1970

The history of the spongology of the Indian Ocean is rather a short one. The area which received some attention in the 19th century was Sri Lanka, and among the earlier major studies dealing with the Sri Lankan species were those of Esper (1798-1806). Ehlers (1870), Haeckcl (1872), Bowerbank (1873), Carter (1880, 1881), Ridley (1884), Dendy (1887, 1889), Sollas (1888) and Lendenfeld (1889). Of the above, the work of Ridley (1884), Sollas (1888) and Lendenfeld (1889) make only occasional references to the fauna of Sri Lanka.

Towards the beginning of the prescnt century there was an cxtensive survey of the pearl banks of Sri Lanka by the Fisheries Department of Sri Lanka.

The large collections made by Prof. Herdman in 1902, were worked out by Dendy (1905). Of a total of 146 species that he described, 77 (52.7%) were new to science.. Considering the• richness, both in number and species Dendy regarded the Gulf of Mannar as 'an extremely rich centre of sponge distribution' , and taking into account the affinity of Sri Lankan sponges with those of the Australian region he, (Dcndy, 1905) included Sri Lanka in the Indo-Australian area, which, at the time of the Challenger. report, included only Australia, East Indies and the Philippines. Burton (1930, 1937) added substantially to our knowledge of the sponge fauna of the Gulf of Mannar, and his latter work, 'The littoral fauna of Krusadai Island in the Gulf of Mannar' is of particular interest for its list of fauna and diagnosis of species. Rao (1941) in a paper 'Indian and Ceylon sponges of the Naturhistoriska Riksmuscet, Stolckholm, collected by K. Fristedt' dealt with 42 species and 3 varieties, of which 7 spccies and 3 varieties were new to science. An extensive survey of the marine sponges, with special reference to those of the Gulf of Mannar and the Palk Bay, was undertaken during the years 1964-67 by Thomas (1968 a), who recorded 125 species of Demospongiae belonging to 84 genera divided among 33 families. Of these 8 species were new to science and 20 were new records to the Indian region The interesting species collected during this survey have been dealt with in greater detail in the subsequent papers (Thomas, 1970a, b, c, d, e). Comparatively very little work has been done on the shallow water marine sponge fauna of peninsular India. Along the east coast, Madras and Chilka Lake were investigated to some extent. Dendy (1887) and Ali (1954, 1956a) worked on the sponge fauna of Madras.

The development of Lissodendoryx simi lis Thiele was worked out by Ali (1956 b) who in a later paper also discussed the ecology of the sponge fauna of Madras harbour (Ali, 1960). Sivaramkrishnan (1951) studied the development and regeneration of CaUyspongia diffusa and Tedania nigrescens from the Madras Coast. The fauna of the Chilka Lake in Orissa was investigated by Annandale (1914, 1915a).

The major studies dealing with the deep sea sponge fauna of the Bay of Bengal are those of Dendy and Burton (1926) and Burton (1928), based on the deep sea sponges colfected by R.I.M.S. 'Investigator' and deposited in the Indian Museum, Calcutta Kumar (1925) reported on the sponges dredged by the Bengal Fisheries steamer 'Golden Crown' Shallow water marine sponges collected from India including Andaman Islands, Bunna and Sri Lanka were studied by Burton and Rao (1932). Of the 82 species reported in this work, 12 species and 3 genera were new. The main works dealing with the calcareous sponges of the Mergui Archipelago received considerable attention from Carter (1887).

The boring sponges of the Indian seas form a group that has been fairly well worked out in the past. The work of Annandale (1915 b) dealing with those of the family Clionidae is an outstanding contribution in this field not only for the significant additions to the fauna but also for the elaborate key and comprehensive diagnosis of 11 species of Cliona and 4 species of Thoosa. The specimens dealt with in this paper were from the Bay of Bengal, Arabian Sea, Persian Gulf and from several other places along the Indian coast. Studics on the same lines were continued in the subsequent work of Annandale (1915 c). Coral-boring sponges of the Gulf of Mannar and the Palk Bay were studied by Thomas (1969 a). About 20 species of boring spong({s have so far been found to infest the coral reefs of lhe Gulf of Mannar and Palk Bay_

The fauna of the west coast of India is rather poorly worked out when compared to that of the east coast. The major contributions dealing with the fauna of the Gulf of Kutch are those of.Dendy (1915, 1916) on Calcarea and non-Calcarea respectively collected by Mr. James Hornell at Okhamandal in Kathiawar, in 1905-1906. The sponge fauna of Karachi has also received some attention, (Kumar, 1924a, b, c; Kumar and Dyal, 1932). Species collected from the Gulf of Kutch, Bombay, Mangalore, Minicoy Island, Cochin, Quiton, Kovalam and Cape Cornorio have been discussed by Thomas (1968 a).

Sponges are well known for their association with other animals and plants. Annandale (1911) discussed in detail the association of some sponges with molluscs of the family Vermetidae from the Bay of Bengal and in a later publication (Annandale, 1914) he dealt with similar association with oysters and mussels from the i\1adras harbour. Devancsan and Chacko (1941) reported the interesting association of the alga, C eratodiclyon spongiosum (Zanard) with the sponge, Sigmadocia fibulala (Schmidt), and also that of the cirripedc, Balanus longirostrum Hock with Spirastrella inconstans (Dendy) from the Krusadi Island. Rao (1914) recorded the association of the alga, P hormedium sponge/iae (Schulze) with Dysidea herbacea (Keller). The association of the holothurian, Chondrocloea striata (Sluiter) with Petrosia testudinaria (Lamarck) has been recorded from the pearl banks of Tuticorin (Nayar and Mahadevan, 1965). The poltychaete Polydora armata Langerhans is also found in association with Aulospongus tubulatus (Bowerbank, 1873; Dendy. 1905, 1921). Spongology of the Indian Ocean in General

The various expeditions conducted in the latter half of the 19th century and the frrst half of the present century have contributed substantially to our knowledge of the sponge fauna of the Indian Ocean.

The expeditions by H.M.S. Albert (1881-1882) Sealark (1905) and John Murray (1933-34) added substantially to our knowledge of the sponge fauna of the Indian Ocean in general and its various islands. Burton (1959) listed 315 species from the Indian Ocean area. The fauna of Seychelles bank received some attention and the latest data has been presented by Thomas (1969).

Papers dealing with the Indian Ocean species in general are those of Carter (1881,1883), Hyatt (1887, 1888), Lendenfeld (1889, 1903), Levi (1964) and Vosmaer and Vemhout (1902). Unfortunately, the 'Challenger' collection added no direct information about the fauna of the Indian Ocean. But the elaborate monographs that appeared as an outcome of this expedition marked considerable advancement in the study of sponges, especially of the deep water forms. Of the 'Challenger' collections, Monaxonida was worked out by Ridley and Dendy (1886, 1887), Tetractinellida by Sollas (1888), Calcarea and Keratosa by Polejaeff (1883, 1884), and Hexactinellida by Schulze (1887).

Hexactinellida of the Indian Ocean is a group which has received considerable attention in the past. The work of Schulze (1887, 1895, 1900, 1902, 1904), Smith (1872), Dendy (1916), Levi (1964) and Burton (1959) from the major contributions in this field. Ijima (1926) 'published a list ofrecognisably known recent Hexactinellids after studying critically all the species collected by the previous authors from this region.

South African sponges have been the subject of intensive investigation in the past. Burton (1926, 1929) studied the Myxospongida, Astrotetraxonida and Lithistidae collected by South Mrican Marine Survey. The order Lithistida, as dermed by Sollas (1888), is a heterogenous group, their diversity suggesting a polyphyletic origin of this order; and Burton (1929) briefly pointed out the affmities of the various genera of this order. Burton studied the sponge fauna of South Africa from different areas like Natal (Burton, 1931, 1933 b), Still Bay (Burton, 1933 a), Oude Kraal, St. James, Seaforth and Muizenberg (Burton, 1936). Other accounts dealing with the South African spongs include those of Kirkpatrick (1901, 1902, 1903 a, 1903 b, 1913), Levi (1963) and Bosraug (1913). The fauna of Madagascar is known from the works of Bosraug (1913), Levi (1956, 1964), Vacelet (1967a, 1967b) and Vacelet and Vasseur (1965). The study of Vacelet (1967 a, 1967 b) brought to light several interesting genera and species of Pharetronid sponges. The fauna of Zanzibar is known from the work of Baer (1905), Jenkin (1908), Lendenfeld (1897) and more recently through the collection made by the 'lohn Murray' Expedition (Burton, 1959).

Accounts of the sponge fauna of Red Sea are available in a number of papers. The first paper by Keller (1889, 1891) who recorded 88 species. In recent years the Israel South Red Sea Expedition (1962), made collections from the'area and these were worked out by Levi (1965), who earlier (1958) identified the samples collected by Calypso. He listed a total of 92 species of which 22 were new to science.

The fauna of the Australian coast has been well explored in the past. Lendenfeld t s monographs and catalogues on Australian sponges, despite their errors and omissions, still remain the classic Areas Investigated 1970-90 work on Australian sponges. Lendenfeld's 'species' were later reinvestigated and revised by many workers and the studies of Hallmann (1914, in three parts), Burton (1927), Whitelegge (1902 b), are worth mentioning in this context. An extensive study of the South Australian sponges, especially those from the neighbourhood of Port Phillip I:leads, was undertaken by Carter in the years 1885-1886. Dendy's monograph of the Victoria sponges appeared in 1891 and his synopsis of the Austalian Calcarea Heterocoela in 1892. This was followed by the catalogue of non¬calcareous sponges collected by Bracebridge Wilson from the neighbourhood ofPort Philip Heads, in two parts (Dendy, 1895, 1896). F.LS. 'Endeavour' conducted extensive fishing experiments in the years 1909-1910 along the coasts of New South Wales, Victoria, Queensland and Tasmania. Monaxonid sponges collected during this expedition were studied by Hallmann (1912) and th same author also revised the family Axinellidae provisionally, including forms having microscleres (Hallmann, 1916, 1917). The major accounts dealing with the Tasmanian sponges are those of Guiter (1950) and Shaw (1927). The sponge fauna of the Western and South-Western Australia also received some attention. Work of Dendy and of Frederick (1924) on the fauna of Abrolhos Island, of Rao and Hozawa (1931) on the Calcarea of South-West Australia, of Hentschel (1909, 1911) and Whitelegge (1905) on the fauna of South-West Australia, of Hentschel (1909, 1911) and Whitelegge (1905) on the fauna of South-West and West Australia, respectively, are the major contributions in this field. The sponges collected by the trawling expedition of H.M.C.S. 'Thetis' resulted in two volumes by Whitelegge (1906, 1907). The fauna of the Indonesian region also has been the subject of extensive study. Ternate sponges were investigated by Kieschnick (1896), Breitfuss (1898) and Thiele (1900, 1903); Amboina sponges by Kieschnick (1898), Schulz (1900), and Topsent (1897); and Aru and Kei Island sponges by Hentschel (1912). Sponges of the Christamos Island were worked out by Dendy (1887) and Kirkpatrick (1900, 1910, 1911).

Spongology of the Indian Seas 1971 to 1990

After 1970, considerable progress has been made in the field of Porifera in India, particularly with regard to systematics. In this context mention may be made to the extensive studies on boring sponges, mainly clionids. Sponges destroying coral reefs (Thomas, 1969) and economically important gregarious molluscan shells of Indian seas were studied in detail, and these deal with a total of 13 genera and 32 species (Thomas, 1979). Estuaries like the Zuari and Mandovi (Goa) were investigated for boring sponges. Five species of boring sponges were present in the inshore realms of Goa, but their number in estuaries was only two. One species (Cliona vastiJica Hancock) could migrate and colonise the rock oyster population common in these estuaries due to its low salinity tolerance. This sort of migration could also be noted in almost all the estuaries of India which were subsequently investigated. Hence this species (C. vastifica) may post a serious threat to any future molluscan farm along Indian estuaries (Thomas, 1975; Thomas and Thanapathy, 1980).

The economically important molluscan beds of the southwest coast of India and also the cultivated stocks at Vizhinjam were investigated in early 1980's for boring organisms with particular reference to sponges. It could be seen that 4 major taxa of marine organisms (sponge, polychaete, bivalve and sipunculid) infest the calcium carbonate secreting animals (such as molluscs, corals and calcareous algae) in the sea. Out of these 4 groups, sponges play an important role in destroying calcium carbonate matter by chipping off minute particles of similar shape and size (microerosion through microchips). Six species of sponges were found to infect the economically important molluscan beds (of mussel, sacred chank, rock oyster, pearl oysters and Thais spp.) in the southwest coast.

It could also be seen that the cultivated stocks of mollusc were more vulnerable to sponge infection than the wild stocks. During these investigations it could also be noticed that two boring species have invaded the Indian molluscan beds around 1980. These have made their first appearance at Vizhinjam on cultivated pearl oysters. These to species (Cliona margarilifera Dendy and C. lobata Hancock) have since then migrated to the natural beds of gregarious molluscs so abundant along the southwest coast of India (Thomas et al., 1983). The nugration pattern of these two invade(s, their incidence and competition with other boring sponge species already available in the various natural beds etc. were ttaced out for a period of eight years (1980-1987). There is a need for a continuous monitoring on the activities of these two species in the various commercially important molluscan beds of the southwest and southeast coasts of India.

Various islands of the Indian Ocean and adjacent seas were surveyed for a detailed documentation of the sponge fauna. The sponge fauna of Lakshadweep was subjected to a thorough study (Thomas, 1973; 1979a; 1980; 1980a; 1988 and 1989) and 91 species of sponges were collected. These 91 species may be classified under 32 genera and 23 families of Demospongiae. 18.species of boring sponges could be collected from various coral atolls and it could be noted that mortality of corals at Lakshadweep was mainly due to the infection of boring sponges. Bioerosion, which is so wide spread in the various coral Islands of Lakshadweep, could also be studied in depth (Thomas, 1988).

Sponge fauna of Seychelles bank was investigated at the request of Koninklijk Museum, Belgium, and sponges collected from Mahe Island were identified (Thomas, 1983a; 1981). The total number of species recorded was 104. Similar collections made from Islands like Mambone, Paradise and Inhaca by the above museum revealed the presence of 46 species referable to 21 families and 36 genera in Inhaca Island and 26 species, 15 families and 22 genera in Mambone and Paradise Islands (Thomas, 1979b; 1979c).

Species collected from Andaman and Nicobar group of Islands from time to time were analysed and found that there were 61 species referable to 44 genera and 2-5 families. Larger specimens were only picked up by various investigators who visited these Islands in the past and such specimens were used as 'source material for chemical studies. So the above number cannot be considered as conclusive. Exhaustive investigation, hence, is necessary to come to any plausible conclusion on the richness of the sponge fauna in these islands~

Maldive specimens were investigated in collaboration with the University of Southern• California, U.S.A. The rust collection from Maldives contained 17 species refemble to 16 genera, of which 3 were new to science.

Areas investigated along the east African coasts were Zanzibar Island, Ras Iwatine and Manbone. Specimens were collected by the East African Marine Fisheries Research Organisation, Mombasa, and the study revealed the presence of 14 species, 13 genera and 10 families in Zanzibar Island (Thomas, 1976) and 10 species, 9 genera and 9 families in the other two localities (Thomas, 1976a).

The inshore realms of the Indian coasts were investigated in detail by the scientists of CMFRI. Besides the above samples the specimen collected and sent for identification by ihose interested in the study of bioactive substances from sponges were utilised for a qualitative appraisal of the sponge fauna of the respective areas. Sponges inhabiting the Gulf of Kutch were investigated and found that the fauna of this area was quite peculiar ecologically as the same was dominated by species that were highly tolerant to silt fall. 25 species falling under 22 genera and 5 families were represented in the Gulf of Kutch collections. Boring sponges were represented by 8 species which preferred dead and living coral skeleton so abundant there (Thomas el al. MS). The sponges of this area may be regarded as a population acclamatised to stressful conditions.

A qualitative appraisal of the sponge fauna of the Gulf of Mannar and Palk Bay was made and a checklist containing 275 species with brief descriptions was published (Thomas, 1986). The sponge fauna of Gulf of Mannar is somewhat well known through earlier wotk, but all the 94 species represented in the Palk Bay were new records for the area. Details pertaining to 275 species of Demospongiae referable to 136 genera and 38 families are provided with suitable illustrations in this paper (Thomas, 1986). .

Fishing/Research Vessels like R. V. 'Klaus Sunnana', R. V. 'Skipjack', and FORV 'Sagar Sampada' have contributed considerably to our knowledge on the deep water sponge fauna of the Indian waters. 'Klaus Sunnana' collected 9 species (including 3 new species) of Demospongiae from depths varying between 180 and 325 m in the Gulf of Mannar (Thomas, 1970). 'Skipjack' owned by CMFRI, collected 8 species (including 3 new) from the southeast coast of India (48m) (Thomas, 1984). Sponges collected by FOR V 'Sagar Sampada' are being investigated for their species composition.

Though sponges constitute a major group among fouling orga~isms in the marine environment nothing is known on the structure and composition of the fauna. Therefore the fouling sponges which migrate and establish the culture rafts at Vizhinjam were investigated and a detailed report was prepared. This report, together with details on boring sponges which infect the CaC03 secreting animals in the Indian seas, was presented at the Specialists' Meet on marine biodeterioration held at Kalpakkam (organised by IGCAR). This paper gives a pictorial key to the identification of various boring spccies (sponges) in the Indian seas (Thomas, 1990).

Sponges collected during the 3rd Indian Antarctic Expedition (Dec. '83 to March '84) from the sea off Queen Maud Land, Antarctica, were studied and reported. Of 6 species-collected 3 were of the Class Hexactinellida and the rest of Demospongiae. One Demospongean specics, viz. I sodictya echinata was new to science (Thomas and Mathew, 1986).

Estimation of Taxa

Phylum Porifera, the only phylum of the Subkingdom Parazoa, has an evolutionary history of about 570 million years. Sponges are represented in the extant oceans by about 5000 species in 790 genera and 80 families. This phylum is represented in the Indian seas by about 203 genera and 486 species. It is divided into 4 classes.

Class I. Calcispongiae (Calcareous sponges)

Typically marinc, spicules made of CaC03 and are not differentiated into mega and microscleres. Total number of species so far recorded is about 500, but Burton (1963) extensively synonymised them to 47 species, and this has made a drastic cut in the Indian Ocean species to 14.

Class II. Demospongiae (Silicious sponges)

Largest group accounting to 95% of the recent sponges. Skeleton made of silica, spongin or with none; some may incorporate foreign objects in,to their body for rigidity. Species are dominantly marine though a family is widely distributed in fresh/brackish water environments. Total number of specics falling under this class is about 4000; 428 in Indian seas.

Class III. Hyalospongiae (Hexactincllid sponges or glass sponges)

Common in deep watcr areas with about 600 species; 44 species are known from Indian seas. Spicules made of silica which are 6-rayed and divisible ,nto mega and microscleres.

Class IV. Sclerospongiae (Coralline sponges)

A recently discovered class with about 15 species; not known from Indian seas yet. Skeleton of silica, spongin and calcium carbonate.

An examination of the sponge fauna of Indian seas reveals that it is dominated by Demospongean spccics (88.80/0) followed by those of Hexactinellida (9.1 %) and Calcarea (2.1 %). This composition is in full agreement with that in the world oceans (Thomas, 1983a). The close relationship of the sponge fauna of the Indian seas with that of the Australian region, Red Sea and the Pacific Ocean is well known. This kind of an affinity is seen not only in the case of sponges but also with regard to every group of marine sedentary organisms (Thomas~ 1983a).

Class Demospongiae is divided into 8 orders. The numerical abundance of various genera and species falling under each order is sumnlariscd. Order Genera Species

It is evident from the above list that the Order Poecilosclerida is the largest and structurally the most diverse order of Demospongiae. Skeleton is composed of a combination of spicule and spongin fibre. Spicules, both mega and micro, may be of different sets with great differentiation in relation to regions of the sponge.

Hexactinellids are typically marine and are common in deeper areas. Skeleton is made of silica and both mega and microscleres have hexactine structure. The classification, here, is based on specific microsclcre type coupled with the arrangement of large hexactinal megascleres, whether separate or fused.

Two orders are considered; Amphidiscophora possessing amphidiscs and Hexasterophora with hexasters, for microscleres. Numerical abundance of genera and species falling under the above two orders is as follows : Calcareous sponges possess spicules of calcium carbonate and a differentiation into mega and microscleres is wanting. This class is divided into 2 families: Homocoelidae and Heterocoelidae. Family Homocoelidae is characterised by the presence of collared cells as a lining in, the whole endosomal cavity and its outgrowths, while in Heterocoelidae no collared cells are found lining the endosomal cavity.

The number of genera and species falling under each family may be given as follows: Burton (1963) in his iconoclastic work on the classification of calcareous sponges has extensively synonymised the then known species. attributing a remarkably wide degree of variability to each species~ He reduced the number of existing genera from 54 to 22 and the number ofspecies from more than 5000 to 47. This resulted in a drastic cut in the total number of Indian Ocean species to 14 wide-spread species; but this procedure is not accepted by several spongologists.

Current Studies

Our know ledge on the Calcareous and Hexactinellid sponges of the lndian waters is still confmed to the classical monographs appeared in the pre-independence period. Larger vessels owned and operated by India can be more effectively used in surveying deeper waters for hexactenillid species which are specific to deeper areas.

Among Demospongiae the freshwater sponge is a group which has been investigated in detail by the scientists of ZSI and universities. Morphology and spicular characters in this family are highly variable and these have resulted in the description of several new species in the past Extensive study giving more importance to environmental factors may' help in cutting down the present number which is so unwieldy for any qualitative assessment of the freshwater sponge fauna as a whole.

Marine Demospongiae, which constitutes the main bulk of the extant sponge fauna is poorly known and this is evident from the number of new species that are added from any locality which is explored for the fIrst time. It is essential that our Demospongean fauna should be properly explored and documented.

Sponges which excavate hard calcareous substrata by chipping off minute particles of calcium carbonate fiom inside weaken the substrata making them more susceptible to vagaries of nature. This type of bioerosion often remains unnoticed in nature since the particles etched out (microchips) are of sUbmicroscopic size. Only a few atolls in the Laksha<Jweep have been investigated in the past by CMFRI as a part of assessing the micro-erosion profile of Lakshadweep in general. Such multidisciplinary studies should be extended to all coral formations along the Indian •coasts.

Boring sponges which cause wide spread mortality to the gregarious molluscs are now knowr. from some selected areas only. When compared to other oceans the number noted in the Indian seas (totally 32) is probably a record number. Apart from the species already present in our seas, it is indicative that 2 species new to the area have invaded our molluscan beds in the recent past. Since these 2 species are capable of devastating any rich molluscan bed within a few days a continuous monitoring of these two species as well as others already present should be initiated on a long term basis in future.

It is heartening to know that many of these 'humble' animals have come to limelight in recent years on account of certain peculiar chemical compounds they contain. Many of these chemicals have biomedical potentials and hence many of them are being screened for 'wonder drugs' Arabinose nucleosides extracted from the sponge Tetya crypta (de Laubenfels) is now used in the treatment of blood cancer and certain malignant tumours with positive results. Cells of some sponges are now employed as mighty tools in immunological studies. Chemicals with antifertility, antimicrobial and antifouling properties have been extracted from several sponges inhabiting our inshore areas.

Some UniversitiesIResearch organisations like Andhra University; lIT, Bombay; CDRI, Lucknow; St. Mary's College, Tuticorin, CMFRI, Cochin etc. are now deeply engrossed in the programme of identifying compounds with biomedical potentials from orgall;isams such as sponges, gorgonids, alcyonarians, corals etc. The main handicap with regard to the progress of such investigations is the poor information on 'source material' and their availability.

Many of the lower invertebrate groups such as sponge, gorgonid, alcyonarian etc. are now being exported for a paltry sum. This has resulted in the depletion of many of our erstwhile rich beds in the recent past. Hence, a. total ban on the exploitation and export of such raw material should be enforced immediately.

It may be apt to point out at this context that our knowledge on the occurrence, availability and species composition etc. pertaining to many of the lower invertebrate groups are still at infancy, and except in a few groups the information available is also not sufficient for initiating any serious study leading to the extraction or synthesis of 'wonder drug' There is a need to develop sufficient number of personnel in various groups of lower invertebrates. for identifying and locating suitable 'source material' that are needed in connection with biomedical investigations in India.

Expertise India

P. A. Thomas, Vizhinjam Research Centre of CMFRI., Vizhinjam 695 521, Kerala.

Abroad

G. J. Bakus, Professor, University of Southern California, Los Angeles, California, U.S.A. P. R. Bergquist, Zoology DepL University of Auckland, New Zealand .. Borojevic Radovan, Universidado Santa Ursula, Rio de Janeiro. W. D. Hartman, Peabody Museum of Natural History, Yale University, New Haven, CT,

M. Koltun, Zoological Institute, Academy of Sciences, Leningrad, U.S.S.R. Levi, Museum. Nat. d'Historic Naturale, 75013 Paris, France. Pravans de Ceccatty, Universite Claude Bernard, Villeurbanne, France. Pulitzer-Finali, Instituto di Zoologica, Balbi-5, Italy. Reutzler, National Museum of Natural History, Smithsonian Institution, Washington, D. C., U.S.A. Sara, Instituto di Zoologica, via Balbi, Genova, Italy. Vacelet, Station Marine d'Endoume, 13007 Marseille, France.

Selected References

Annandale, N. 1915 b. Indian boring sponges of the fal}lily Clionidae. Rec. Indian Mus., 11 : 1¬ 24. Annandale, N. 1915 c. Some sponges parasitic on Clionidae ~'ith further notes on that family. lbid., 11 : 457-478.

Bwton, M. 1963. A revision of the classification of the Calcareous sponges. British Mus. (Nat. Hist) Publ., pp. 1-693. Burton, M. &Rao, H. S. 1932. Repolrts on the shallow-water marine spognes in the collection of the Indian Museum. Rec. Indian Mus., 34 : 299-356.

Dendy, A. 1887. The sponge fauna of Madras. A report on a collection of sponges obtained in the neighbourhood of Madras by Edgar Thurston. Ann. Mag. nat. Ifisl., 20(5) : 153-164. Dendy, A. 1915. Report on the calcareous sponges collected by Mr. James Hornell at Okhamandal in Kattiawar in 1905-1906. Rep. Govt. Baroda Mar. Zool. Okhamandal,2: 79 ..91. Dendy, A. 1916. Report on the non-calcareous sponges collected by Mr. James Hornell at Okhamandal in Katti~war in 1905-1906..Jbid., 2 : 96-146.

Dendy, A. &Burton M. 1926. Report on some deep-sea sponges from the Indian Museum collected by R.I.M.S. Investigator. I. Hexactinellida and Tetraxonida (Pars). Rec. Indian Mus., 28 : 225-248.

Kumar, D. A. 1925. Report on some Tctraxonid spongs in the collection of Indian Museum. Rec. Indian Mus., 27 : 211-229.

Thomas, P. A. 1976. The history of spongology of Indian Ocean. J. mar. bioi. Ass. India, 18(3) : 610-628 (This contains a number of other references).

Thomas, P. A. 1979. Boring sponges destructive to economically important molluscan beds and coral reefs in the Indian seas. India J. Fish., 26(1&2): 163-200.

Thomas, P. A. 1983a. Distribution and affinities of the sponge fauna of the Indian Ocean. J. mar. bioi. Ass. India, 25(1&2): 7-16.

Thomas, P. A. & Mathew, K. J. 1986. Sponges collected during the Third Indian Antarctic Research Expedition with descriptions of I sodictya echinala Sp. Nov. Third Indian Expedition to Anlarctica, Scientific Reports, 1986. DOD Technical Publication No.3: 109-116. Vosmaer, G. C. J. 1928. Bibliography of sponges. Cambridge University Press. pp. 1-234.

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