[1] It is known to occur in four different localities in the Fukushima and Niigata Prefectures,[2] including Tadami and Sanjō.

[3] The species grows 14 centimetres (5.5 in) to 16 centimetres (6.3 in) long,[3] and differs from the Japanese clawed salamander (O. japonicus) by having a long tail and wide head, as well as lacking a dorsal stripe.

[2] O. fuscus lives in streams[3] and breeds during the winter.

[2] The species is closely related to Onychodactylus intermedius.

It shares much of its habitat with O. japonicus, but the two species are reproductively isolated.