A new genus and species of freshwater crab (Crustacea, Decapoda, Potamoidea) from northern Madagascar, and a second new species associated with Pandanus leaf axils

Two new species of freshwater crab are described from Madagascar, one from streams in a high-elevation locality, and the other from Pandanus leaf axils in low altitude localities. The unusual combination of characters of the new high-elevation species warrants the establishment of a new genus to accommodate this taxon. The new taxa are compared to the other species of freshwater crabs occurring in Madagascar, including Gecarcinautes antongilensis vondrozi Bott, 1965, which is considered here to be a synonym of G. antongilensis (Rathbun, 1904). Both of the new taxa are endemic to Madagascar, as are all of the genera and species of freshwater crabs found on the island.