The gecarcinucid freshwater crabs of southern India (Crustacea: Decapoda: Brachyura)

The freshwater crab fauna of the two southernmost Indian states of Kerala and Tamil Nadu are reviewed based on the findings of a recent field survey and re-examination of relevant type material. Nine genera and twenty-three species of gecarcinucid freshwater crabs are reported, including six new genera (Baratha, Lamella, Pilarta, Snaha, Vanni and Vela) and 10 new species (Baratha pushta, Baratha peena, Pilarta anuka, Snaha aruna, Travancoriana kuleera, Travancoriana charu, Vanni ashini, Vanni deepta, Vanni giri and Vela virupa). Four species previously regarded as junior subjective synonyms are recognised herein as valid species, namely, Lamella lamellifrons (Alcock), Vela pulvinata (Alcock), Vanni travancorica (Henderson) and Travancoriana convexa (Roux). Keys to the genera and species of southern Indian gecarcinucid freshwater crabs are provided.