本属のうち3種が西部北大西洋から知られ,O. chickcharneyとO. dormitatorは体に斑紋がなく背鰭軟条が111〜117本と多い(Böhlke and Robins, 1959)。 (荒井)
Distinctive characters:
(Family):Gill opening wide. Dorsal, caudal, and anal fins continuous. Anterior nostril well above upper lip. Supramaxillary present. (Genus):Pelvic fin inserted below orbit. A blunt spine present on dorsal aspect of snout. Barbel absent. Body scales elongate or elliptical, arranged at oblique angles to each other. Head naked. Dorsal finrays less than 150; anal finrays less than 125. (Species):A distinct black blotch present just above gill cover; two or three rows of dark brownish blotches on body; dorsal fin with blackish blotches along margin; anal black; caudal pale. Snout spine situated between posterior nostrils and covered with skin. A wide, flat spine on opercle. Gill rakers short.
Distribution:
Middle western Atlantic.
Remarks:
In the western North Atlantic, three species of the genus, O. chickcharney, O. dormitator, and O. omostigmum, are reported, the former two species have no blotches on body and dorsal with 111〜117 fin rays (Böhkle and Robins, 1959). (Arai)