(Family):Dorsal and anal fins without spine. Pelvic fin with 1 spine and 6 soft rays. One large supramaxillary. No lateral line. Small ctenoid scales on side. (Genus and Species):Profile of body circular. Anus locating just before anal fin. Scutes on ventral midline before pelvic fin. Radial ridges 30〜33 on opercle.
Distribution:
Deep sea of tropical regions in Atlantic, Indian, and Pacific Oceans.
Remarks:
Monotypic genus. Another genus of this family, Diretmoides, is distinguishable from this genus by anus locating at midpoint between pelvic and anal fins, and no scutes on ventral midline before pelvic fin. (Uyeno and Sato)