The identity of the Japanese freshwater crab, Geothelphusa dehaani (White, 1847) (Decapoda: Brachyura: Potamidae), with descriptions of two new species from Japan

Abstract

This study designates a lectotype for and redescribes Thelphusa dehaani White, 1847, a Japanese primary freshwater crab species belonging to the potamid genus Geothelphusa Stimpson, 1858. Geothelphusa dehaani was described based on material exported to the Netherlands by von Siebold. Although the provenance of all his specimens is uncertain (they may be from several locations), our morphological comparison of the lectotype with fresh specimens led us to ascertain that it was almost certainly collected from Nagasaki, where von Siebold stayed. Two new Geothelphusa species are also described from Amakusa Islands and Aomori Prefecture.