New Records of Four Grapsoid Crabs (Crustacea: Decapoda: Brachyura) from Japan, with Notes on Four Rare Species

Four species of semiterrestrial grapsoid crabs are recorded from Japanese waters for the first time based on material from the Ryukyu Islands. These are: Pachygrapsus planifrons De Man, 1888 (Grapsidae); Nanosesarma andersoni (De Man, 1888), Sesarmoides kraussi (De Man, 1887), and Stelgistra stormi (De Man, 1895) (Sesarmidae). Supplementary information is provid­ ed for four other little known species, three sesarmids Clistocoeloma villosum (A. Milne-Edwards, 1869), Metasesarma obesum (Dana, 1851) and Perisesarma semperi (Burger, 1893), and one varunid Ptychognathus capillidigitatus Takeda, 1984. The generic assignment of C. villosum is briefly discussed. The range of P. capillidigitatus is extended south to Iriomote Island.