Schubartamon serenum new genus and species, a troglobitic crab from Laos, new records of Erebusa calobates Yeo & Ng, 1999 (Decapoda, Brachyura, Potamidae), and insights on the potamid genera of Indochina

Abstract A new genus and species of troglobitic potamid crab, Schubartamon serenum gen. nov., sp. nov., is described based on an adult female from Vientiane province, Central Laos, found in Vang Vieng karst in the cave Tham Nang Oua (also called Tham Nang Hua). The new genus can be clearly distinguished morphologically from Erebusa , another troglobitic genus known from the single species E. calobates , also from Central Laos, in the Khammouan karst, and for which we now have additional material collected by two French expeditions in several caves scattered around this province, enabling the species to be better documented. The immense karst of Khammouan is not very fragmented, so that the dispersal of species can be quite possible, which explains why E. calobates can be found there dispersed across distant caves. Schubartamon serenum gen. nov., sp. nov. has been collected much further north, in the Vang Vieng karst, Vientiane province, more than 400 km north of Thakhek, the capital of Khammouan. The two species share similar troglobitic adaptations, but the morphological differences between them are significant at a generic level. In particular, compared to those of E. calobates , the differently shaped vulvae of S. serenum gen. nov., sp. nov. alone represent an excellent character for generic distinction. A review of the potamid genera of Indochina is also presented.