Description of a new species of Richalpheus Anker and Jeng, 2006 (Crustacea : Decapoda : Alpheidae) from the Red Sea

Richalpheus dahabensis n. sp. is described from a single female specimen collected at a depth of 10-13m from the mound of the callianassid mudshrimp, Glypturus sp., in the shallow lagoon near Dahab, Egyptian Red Sea. The new species differs from the type species, R. palmeri Anker and Jeng, 2006, by the absence of the fossa/tooth system on the pollex of the major chela. The diagnosis of Richalpheus is emended to accommodate the new species. The two possible pathways for the evolution of the fossa/tooth system within the leptalpheoid lineage are discussed.