A new species, Mursia coseli , is described from specimens collected in the Mozambique Channel, off Madagascar. It is compared to the two other species of the genus known from this area, M. africana Galil, 1993 and M. flamma Galil, 1993, from which it can be distinguished by, among other characters, the shape of the second pleopods. The species nearest to M. coseli is M. danigoi Galil, 1993, known only from the Philippines. The two species can be separated by the granulation of the carapace and the slenderness of the pereiopods.
Crustacea, Decapoda, Brachyura, Calappidae, Mursia, deep water, Indian Ocean, Madagascar, new species.