Pachystomias Gunther, 1887
Diagnosis: body moderately long, its depth less than 10 times in SL. Head with short, rounded snout; lower jaw not longer than upper jaw, not curved strongly upward; barbel slender, generally shorter in larger fishes, maximum half of SL, minimum less than eye diameter, its tip unmodified. Pectoral fin with 46 finrays, all about equal in length, unbranched distally, and without lumps of luminous material; pelvic fins low on body, their insertions close together near mid-ventral line; bases of dorsal and anal fins about equally long, their origins approximately opposed; no dorsal adipose fin. Photophores in ventral row between pectoral and pelvic fin insertions (PV) 15-18; post-orbital luminous organ small, roundish, less than half eye diameter; pre-orbital organ present at antero-ventral margin of eye, rounded or ovoid in shape; sub-orbital organ prominent, forming a semicircle under most of ventral margin of eye; no large patches on head behind eye. Colour: head and body black; no pale loop or line on sides. Size: to more than 22 cm.
Habitat, etc.: see family.
Distribution: known from 50° N, 20° W and off north-western Portugal. Elsewhere, eastern Atlantic from the Cape Verde Is. to off South Africa; North Atlantic between 30° and 40° N; Lesser Antilles; Indian and Pacific Oceans.
Recent revisions: Regan and Trewavas (1930), Morrow and Gibbs (1964), Goodyear (unpublished Ph.D. thesis, 1980).
Species of this genus in the program:
Pachystomias microdon