Taxonomy of mudcrabs of the genus Scylla (De Haan) from Cochin Backwaters, Kerala, India

Abstract

The present study was carried out to resolve the species ambiguity of Scylla species found in Cochin Backwaters, Kerala, India by anlysing 365 adult mudcrabs (211 males and 154 females). The work focused mainly on the description of the species based on morphological characters, specifically the first and second pleopods and the third maxillipeds which are commonly used for the identification of closely related species of crabs. These structures were dissected out, examined under a binocular microscope and described with the help of camera lucida drawings. Two species of Scylla were identified and the structures revealed remarkable variations between them. Earlier works reported the existence of two species of mudcrabs, viz., Scylla serrata and Scylla tranquebarica in Cochin Backwaters. But results of the present study indicated that the species occurring in Cochin Backwaters are S. serrata and S. olivacea. The present study also reports the occurrence of S. olivacea in Cochin Backwaters for the first time, on the basis of valid classical taxonomic evidence.