On the taxonomy of a sesarmid crab, Sesarma lanatum Alcock, 1900 (Crustacea: Decapoda: Brachyura: Sesarmidae) from India

The sesarmid crab, Sesarma lanatum Alcock, 1900, is originally described from Pakistan and India. Previous studies have suggested that S. lanatum should be placed under the genus Clistocoeloma, but its morphological affinities with the genus have not been discussed in detail. In the present study, we examined the existing syntype female and fresh specimens of S. lanatum collected from Gujarat state; the specimens show full agreement with the generic characters of Clistocoeloma. To stabilize the taxonomy of the species, S. lanatum is confirmed as a species of Clistocoeloma and the syntype female specimen is designated as the lectotype to fix the identity of the species. The present study provides detailed redescription and illustrations of C. lanatum based on the lectotype and other specimens, and its taxonomic affinities with closely related species have been discussed.