On the occurrence of Athanas dorsalis (Stimpson)(Decapoda - Alpheidae) in the Gulf of Mannar

Abstract

Banner (1960) in a revision,of the genus Athanas Leach has provided a key for the identification of the species belonging to this genus from the Indo-Pacific region. The genus Athanas, which was once separated from a closely related genus Arete Stimpson based on the number of segments of carpus in the second pereiopod (5 in Athanas aind 4 in Arete) and biunguiculate third pereiopod in Arete and uniunguiculate in Athanas, has already been merged together (Banner 1960) and Arete now stands as a synonym of Athanas. Of the 28 species so far known from the whole of the Indo-Pacific region, only 8 species are known to occur in Indian Ocean. Out of the above 8 species, only 1 species is on record from the coasts of Indian Peninsula (Kemp 1915). Except for A. orientalis Pearson and A. polymorphus Kemp, which appear to be endemic in distribution (A. orientalis was reported from Ceylon and A. polymorphus from Chilka Lake), the rest of the 6 species have all a very wide range of distribution at least from the east coast of Africa to Indonesia. This evidently indicates that alpheids as a whole is so far a little known group as far as Indian region is concerned and except for the exhaustive accounts by Coutiere (1903 & 1906), who made a thorough study of alpheids of the Laccadive and Maldive Archipelagos, there is practically no work dealing with this group of decapods.