A taxonomic revision of the freshwater crab genus Barytelphusa Alcock, 1909 (Decapoda: Brachyura: Gecarcinucidae), with descriptions of a new genus and three new species

Abstract

Abstract The taxonomy of the gecarcinucid crab genus Barytelphusa Alcock, 1909, native to peninsular India, is revised. The genus was formerly known from as many as 13 species and four varieties. We examined their name-bearing type specimens, and to stabilise their taxonomy, designated lectotypes for Potamon (Potamonautes) jacquemontiRathbun, 1905, Thelphusa guerini H. Milne Edwards, 1853, and Telphusa pocockianaHenderson, 1893, and a neotype for Thelphusa cunicularis Westwood in Sykes, 1836. With most of the species already assigned to other genera in previous works, we restrict Barytelphusa s. str. further to only two species, i.e., Barytelphusa cunicularis (Westwood in Sykes, 1836), and a new species described herein, Barytelphusa inflatasp. nov.Potamon (Potamonautes) jacquemonti, the type species of the genus, is here synonymised with Barytelphusa cunicularis. A new genus, Barusagen. nov., is established to accommodate two species placed previously in Barytelphusa (Thelphusa guerini and Paratelphusa (Barytelphusa) mccanniChopra & Das, 1935) and two new species (Barusa gracillimasp. nov. (type species) and Barusa obesasp. nov.). Thelphusa planata A. Milne-Edwards, 1869, and Telphusa pocockiana remain as junior synonyms of Barusa guerini (H. Milne Edwards, 1853) comb. nov.Barusagen. nov. resembles Barytelphusa but can be differentiated by several significant characters of the carapace, antennae, cheliped, male pleon, and male first gonopod. Identification keys to the species of both genera are provided. The taxonomy of Potamon napaeum Alcock, 1909, placed previously in Barytelphusa, and more recently in TravancorianaBott, 1969, is also clarified, and the species is now reassigned to MaydelliathelphusaBott, 1969.