A new species of freshwater crab (Brachyura : Potamoidea : Potamonautidae) from the Ruwenzori region of western Uganda, East Africa

We report here on a collection of freshwater crabs of the family Potamonautidae Bott, 1970 from Uganda, East Africa, as part of a study on the relationships between freshwater crabs and river blindness (onchocerciasis). The collection comprised more than a hundred specimens belonging to two species of Potamonautes MacLeay, 1838, P. aloysiisabaudiae Nobili, 1905, and P. rukwanzi, new species. The new species described here was collected from an isolated crater lake in the Ruwenzori Mountain region of western Uganda. The species is distinguished by a combination of characters of the carapace, abdomen, sternum, chelipeds, and the first gonopod. Intraspecific comparisons between adults, subadults and juveniles, and between males and females, are also presented. The addition of P. rukwanzi, brings to twelve the number of species of freshwater crabs reported from Uganda.