A new semiterrestrial freshwater crab in the genus Badistemon and a new record of Indochinamon from northern Thailand (Brachyura: Potamidae)

A new species of semiterrestrial freshwater crab, Badistemon nanensis, is described from northern Thailand, some 750 km from its nearest reported congener. The new species is diagnosed primarily by the unique form of the gonopod I and H, the degree of fusion in the anterior thoracic sternites, the form of male pleon somite VI, the male telson, and the form of the chelipeds. This new species is only known from the type locality. In addition, this new species was found to co-occur with Indochinamon bhumibol (Naiyanetr, 2001), which represents a 350-kin range extension for that species. Both crabs are important local foods for humans.