<i style="">Sepia prabahari</i> sp. nov. (Mollusca/Cephalopoda), a new species of Acanthosepion species complex from Tuticorin bay, southeast coast of India

45-51A new cuttlefish Sepia prabahari sp. nov. collected from Tuticorin bay(8o47’N, 78o9’E) is described with a comparison of the closely related species Sepia pharaonis. Sepia prabahari sp. nov. shows a clear-cut sexual dimorphism with respect to length and shape of arms. In males, first and fourth pair of arms distinctly extended and whip like. However, in females, first and fourth arms are neither distinctly extended nor whip like. Sepia prabahari sp. nov. closely resembles the juvenile of Sepia pharaonis as both of them have distinct tiger-stripe pattern on the dorsal side of the mantle. However, Sepia prabahari sp. nov. can easily be distinguished from the closely related species S.pharaonis based on the arrangement of suckers in the tentacular club. The tentacular club of S. prabahari sp. nov. is with minute suckers of equal size without any enlarged suckers, in contrast to that of S. pharaonis with big suckers, of which about 6 suckers in medial rows are much enlarged. In S .prabahari sp. nov. the left ventral arm of male is hectocotylised with 8 transverse series of normal basal suckers followed by 7 series of modified suckers, in contrast to 10-12 basal transverse series of normal suckers followed by 7 series of modified suckers in S.pharaonis. Further, S prabahari sp. nov belongs to Acanthosepion species complex (Rocheburne, 1884) as its inner cone of the cuttlebone is distinct, forming rounded and cap-like cavity in contrast to that of plate like callosity in S.pharaonis and hence belongs to Sepia sensu stricto species complex. The diagnostic characters of the species belong to the Acanthosepion species complex of the genus Sepia of Indian waters with that of S. prabahari sp. nov. are also discussed