Common Name
Japanese Assfish
Year Described
Machida, 1989
Identification
Dorsal Fin: 115-126
Anal Fin:
Pelvic Fin: 1
Pectoral Fin:
Caudal Fin:
Gill Rakers: (long rakers on first arch)
Vertebrae: 13-14 (precaudal), (caudal), 64-68 (total)
Oblique Scales:
Body elongate, compressed, and tapering strongly post-anus. Body depth % SL. Head large (HL % SL). Mouth inferior. Anterior nostril on snout, posterior between front nostril and eye. Eye small. Mouth large, extending well past orbit. Rear of maxilla expanded. Tooth patches present on dentary, palatine, and basibranchial (one median patch). Vomerine patch usually absent. Teeth tiny and conical. Preopercle lacks spines. Opercular spine weak. Dorsal and anal fins continuous with tail. Dorsal fin origin between preopercle and pectoral base (predorsal length % SL). Anal fin base averages under the Xth dorsal fin ray. Dorsal fin slightly higher anteriorly. Caudal fin present but small. Pectoral fin moderate, at eye level, and fan-like. Pelvic fin origin anterior to preopercle and not reaching anus. Body flabby and weakly muscled. Cycloid scales cover head and body but absent on jaw. Lateral line absent.
Color
Body and head medium to dark chocolate brown. Gill area, fin edges, and gut blackish.
Size
Known specimens range from 185–805mm SL.
Habitat
Abyssal depths over soft bottoms (3965-5606m).
Range
Known from the Caribbean Sea and several locations in the eastern Atlantic. Also in the Indian and Pacific Oceans.
References
Ohashi, S., and G. Shinohara. 2015. An Additional Record of Bassozetus levistomatus Machida, 1989 from the Western North Pacific (Teleostei, Ophidiiformes, Ophidiidae). Bull. Natl. Mus. Nat. Sci. Ser. A, 41, 69-75.
Tomiyama, S., M. Takami, and A. Fukui. 2018. A new deepwater assfish, Bassozetus nielseni sp. nov.(Ophidiiformes: Ophidiidae), from the North Atlantic and West Indian oceans. Ichthyological Research, 65, 353-362.