a genus of caudate amphibians of the family Hynobiidae.
Members of the genus Onychodactylus reach a length of 20cm, including a long tail. There are two species: O. fischeri (found in the Far East, northeastern China, and Korea) and O. japonicus (on the islands of Honshu and Skikoku). The animals inhabit cold mountain streams and have no lungs; the adults breathe only through the skin and through the mucous membrane of the mouth. The larval period lasts a minimum of two years. The toes of the larvae have claws. These are partially retained in the adults.