A new genus and new species of freshwater crab (Potamoidea, Potamidae) from Socotra Island, Yemen

Abstract

A new species of freshwater crab from the semi-arid highlands of Socotra Island, Yemen, is described. The unusual combination of characters of these specimens warrants the establishment of a new genus (Socotra) to accommodate the new species. The new taxon is compared to Potamon socotrensis, the other species of freshwater crab occurring in Socotra. The two species of freshwater crabs on Socotra (Potamon and Socotra) are both endemic and both show affinities with the Potamidae, a freshwater crab family with a wide distributional range that includes north-west Africa, south-east Europe, the Middle East, the Himalayas, South-East Asia and China. Perhaps surprisingly, given the close proximity of the island to the coast of Africa, the Socotran freshwater crabs were not found to be closely related to the freshwater crab families found in East Africa (Potamonautidae and Deckeniidae).