Abstract
The Asian goby genera Chaenogobius Gill and Gymnogobius Gill, the two Western North Pacific representatives of the Chasmichthys Group, are revised. A key is provided for each genus. Chaenogobius includes two species found in shallow marine waters along the coasts of Japan and the Korean Peninsula. Gymnogobius includes thirteen species found in shallow marine, brackish, and fresh waters throughout Japan, the Russian Far East, the Kuril Islands, the Korean Peninsula, and the Yellow Sea. A new species, Gymnogobius opperiens, is described from Japan, the Russian Far East, and the Kuril Islands, and a species previously thought to be undescribed is recognized as Gymnogobius petschiliensis (Rendahl, 1924).