The Bathysauridae are a small family of deepwater aulopiform fish, related to the telescopefishes. The two species in the family both belong to the genus Bathysaurus. Commonly called deepwater lizardfishes or deepsea lizardfishes, the latter name usually refers to the species B. ferox specifically. Physically, the bathysaurids resemble the lizardfishes, as reflected in their common names. They can be distinguished from the lizardfishes by their flatter heads and curved and barbed teeth. They are moderately sized fish, up to 78 cm (31 in) in length.