A new cavernicolous species of crab of the genus Balssiathelphusa Bott, 1969 (Crustacea, Brachyura, Gecarcinucidae) from eastern Borneo

A fourth species of gecarcinucid freshwater crab of the genus Balssiathelphusa Bott, 1969, is described from a cave system in eastern Kalimantan, Indonesia in Borneo. It is closest to B. cursor Ng, 1986, from Kalimantan, but can easily be distinguished from congeners by its relatively wider carapace, elongated ambulatory legs and characteristic male first gonopod structure. Although found only in caves, it is not regarded as a troglobite because its eyes are not reduced and the cornea are fully pigmented.