Osteology and ontogeny of the wrymouths, genus Cryptacanthodes (Cottiformes: Zoarcoidei: Cryptacanthodidae).

The four species included in the family Cryptacanthodidae are eel-like, burrowing fishes distributed in the cold-temperate coastal waters of the North Pacific and the western North Atlantic. This study describes the osteology and aspects of the ontogenetic skeletal development of two species, Cryptacanthodes maculatus from the western North Atlantic and C. aleutensis from the eastern North Pacific. We discuss the relationships of Cryptacanthodidae among other zoarcoid families. The Cryptacanthodidae have been previously included in the Stichaeidae, but removed and classified as a separate family based on the skull, pectoral radial, and cephalic lateral-line morphology. Our observations (similarities in gill arch and pectoral girdle morphology; specifically, a thin sheet-like flange of bone from the posterior margin of the supracleithrum) suggest a close relationship to at least some of the members of the family Stichaeidae.