A New Species of the Commensal Crab Genus Aphanodactylus (Crustacea : Brachyura : Pinnotheridae) from the Yaeyama Islands, Southern Japan

Abstract

A new commensal crab, Aphanodactylus loimiae, is described from the Yaeyama Islands, Okinawa Prefecture, Japan. The present species is the third species of this rare pinnotherid genus. It differs from the two previously known species in carapace shape, number of segments of anntennal flagellum, and number of merus teeth on walking legs. The single specimen was found in the tube of a sessile polychaete, Loimia ingens Grube. A dichotomous key and a diagrammatic key to the subfamilies of the Pinnotheridae and the genera of the Asthenognathinae in Japan are given.