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Protochordata

Introduction

Protochordata comprises of two sub-phyla, Cephalochordata and Tunicata. Sub-phylum Cephalochordata has Class Leptochordii. Tunicata has three Classes, viz. Ascidiacea, Thaliacea "and Larvacea. The protochordates are exclusively marine and occupy various niches in the marine ecosystem. The present status of our group in India is as such based on the work done on the Marine Survey Collections made on board R.I.M.S. "Investigator" , the vessels in the Pearl Oyester fisheries, the collections made by the Central Marine Fisheries Research Institute on board the R. V. Varuna, collections made by the various university laboratories of the maritime states and the"collections of the International Indian Ocean Expedition.

Historical Resume

Cephalochordata : Gray (1847), Thurston (1890), Tattersall (1903) and Foster-Cooper (1903) worked on the samples collected from the Indian Seas, including the Laccadive &Maldive Island collections. Prashad (1934) worked on the collections available in the Zoological Survey of India and described four species. Azaria (1963, 1966, 1967), working on the collections made off Madras coast has described three species.

Ascidiacea: Herdman's (1906) description of ascidians from the Gulf ofMannar was the rust on Indian ascidians. Oka (1915), a visiting Japanese Scientist, worked on the deep sea collections made on board R.I.M.S. "Investigator" and described "II new species .belonging to the families Cynthidae, Styelidae, Ascididae and Clavinidae, which included an aberrent. deep sea form, Hexacrobilus indicus. Das (1936-'45) and Sabestian (1942-59) worked on the ascidian fauna of the Madras coast; the former studied Pyuridae while the latter covered the families Polyclinidae, Peraphoridae, Pyuridae and Styelidae. Prakasam (1978) in his short work, added knowledge to the fauna of Madras coast. Ranganathan (1982-1988) has extensively covered various families of ascidians from his collection off southeast coast of India. From the Bombay coast, Karande (1969) noted six species of ascidians acting as foulers in the harbour. Miller (1988) worked on the ascidians brought by the International Indian ocean Expedition team.

Thaliacea: Bomford (1913) initiated the study on salps collected on board R.I.M.S. "Investigator" and this was followed by Sewell (1926) to complete a monograph. Nair &Aiyer (1943) and Nair (1949) recorded sixteen species of pelagic tunicates (salps &doliolids) collected off Madras coast. Ganapatby &Bhavanarayana (1958) gave a list of pelagic tunicates (salps, doliolids and Larvacea) and pointed out their significance as indicators of ocean currents in Bay of Bengal. Sabestian (1968) described a new encrusting species of Pyrosoma from the Arabian Sea. Swarming behaviour of salps were observed by Nagabhushanam (1960) off Andhra coast and by La! Mohan (1965) off Gujarat coast. Dhandapani (in press) presented a paper in the Symposium on Indian ocean and adjacent seas at Cochin, in which he indicated the presence of fourteen species of doliolids (including new taxa) in the Arabian Sea. Dhandapani (1977) described eight species of doliolids including new records from the Bay of Bengal. Van Soest (1981) has published monograph on Pyrosmatida in which he described several new species from Indian Seas.

Larvacea : Fenaux (1974), working on the International Indian ocean Expedition material; has described many species of appendicularians from the Bay of Bengal. Chandrika (1974) recorded a rare appendicularian of the family Kowlevskidae. Dhandapani (1977) described two new species of Larvacea from the Bay of Bengal.

Dhandapani (1977) has worked out the collections made on board the vessels R.I.M.S. "Investigator" ,R.V. "Vityaz" and I~.S. "Kistna" and added two new species of appendicularians, five species of doliolids and one species of Amphioxids •as new to Bay of Bengal. Three species of salps and eighteen species of Larvacea have been added as new to National Zoological Collections. The collections of I.N.S. "Dharshak" and those of F.D.R.V. "Sagar Sampada" are being worked out for Protochordata.

In India, Ranganathan (Hindu College, Tuticorin), Jayapaul Azaria (Zoot. Dept, University of Madras) and Bhavanarayana (Zool. Dept., Andhra University) continue to work on Ascidiacea, Cephalochordata and Salpida respectively.

Scientists outside India are interested on diversified aspects of the subject, i.e. physiology, embryology, cytogenetics, cytochemistry and computer analysis of the population, etc. Monniot (Museum Nationale de Historie Naturalle, Paris), Patricia Kott (Queensland Museum, Australia), Miller (Marine Laboratory, Scotland), Jefferies, (British Museum of Natural History, London), Tokioka (Seto Marine Biological Laboratory) are interested in taxonomy of ascidians. Godeaux (Institute of Van Beneden, Belgitlm), Bracconot (Statione Zoologique, France), and Van Soest (Zoological museum, Amsterdam) are experts in Thaliacea. Feneau, (Station Zoologique, France) is an expert on Larvacea. Tokioka (Seto Marine Biological Laboratory, Japan) is interested in all groups of pelagic tunicates.

Areas to be Explored

Survey : Dredging should be undertaken beyond 100m level all over Indian Ocean and its insular waters. This will help to have more knowledge on benthic fauna of Protochordata.

Taxonomic study: Among sessile tunicates, families Polycitridae, Dideminidae, Diazinidae, Cionidae, Corellidae, Octonimidae. Sortillidae and Molgulidae are to be worked out

Estimation of Taxa

Expertise India

In ZSI

P. Dhandapani -Marine Biological Station, Zoological Survey of India, Madras ¬[Protochordata except ascidians].

Elsewhere

P. V. Bhavanarayana, Dept. of Zoology, Andhra University, Visakhapatnam -3. [Salpida]. Jayapaul Azaria, Dept. ofZoology, University of Madras, Madras -20 [Cephalocbordata].

T. Ranganathan, Dept. of Zoology, Hindu College, Tuticorin, Tamil Nadu -[Ascidiacea].

Abroad

N. J. Berrill, 410, Swathmore Avenue, Swathmore, Pennsylvania, U.S.A. [Tunicata].

J. C. Bracconor, Station Zoologique, Villefranche -sur. Marine, France [Doliolida].

R. Feneaux, Station Zoologique Villefranchesur, Marine, France. [Larvacea].

R. W. M. Van Soest, Institute of Taxonomic Zoologic, University of Amsterdam ¬[Thaliacea].

H. John, Wickstead, The Marine Biological Association, Citadal Hill, Plymouth, England -[Cephalochordata].