Freshwater Crabs and Shrimps (Crustacea: Decapoda) of the Nile Basin

Abstract

Freshwater crabs are present in almost all freshwater bodies in the Nile River basin ranging from the main river to mountain streams, and from extensive wetlands to rift valley lakes, but these decapod crustaceans are absent from the more arid regions of the Sahara and East Africa. Some 14 species of freshwater crabs (Potamonautidae) and six species of shrimps (Atyidae, Palaeomonidae) are found in the eight African countries that have at least part of their territory in the Nile drainage. The most species rich country in the Nile basin is Uganda (with more than 12 species), while the vast desert countries of The Sudan and Egypt are rela- tively species poor and have no endemic species of freshwater crabs, and Ethiopia (although not species rich) has both widespread and endemic species. There is a clear biogeographic and taxonomic divide between the freshwater crab fauna of the Nile catchment which differs significantly from the species groups found in the neighboring Congo basin (Rwanda, Burundi, and D. R. Congo).