Apristurus longicephalus

Author: Nakaya, 1975

Field Marks:
An Apristurus with an unusually long snout, about 12% of total length.

Diagnostic Features:
Body relatively slender, trunk slightly tapering toward head. Snout long, basally broad but distally narrowly parabolic and bell-shaped, preoral snout about 12% of total length; gill slits small, less than eye length; gill septa without projecting medial lobes or pleats, hardly incised; eyes rather small in the type, about 3% of total length; nostrils broad, their width about 1.3 times in internarial space; incurrent and excurrent apertures very large and oval, anterior nasal flaps long and angular; mouth fairly short, moderate-sized and broadly arched, with dental bands slightly expanded and with lower ones falling just behind uppers; mouth under eyes and upper labial furrows extending slightly in front of them; labial folds somewhat enlarged, with lower nearly transverse to body axis. Interdorsal space slightly greater than first dorsal base, about half preorbital snout, first dorsal fin smaller than second, its base about 2/3 length of second; origin of first dorsal opposite rear third of pelvic bases; second dorsal insertion opposite to anal insertion; pectoral fins rather small, anterior margins about 12% of total length; inner margins long, nearly length of pectoral bases; interspace between pectoral and pelvic bases very short, slightly less than prenarial length and about 6% of total length in holotype; pelvic fins moderately high and broadly rounded; anal fin very long, low, and angular, about a fifth as high as long, its base almost equal to prespiracular space and 15% of total length; caudal fin long and narrow, without a dorsal crest of enlarged denticles. Lateral trunk denticles of body with crowns fairly flat and wellseparated, surface apparently smooth and without a feltlike or fuzzy texture. Colour grey-black, without Conspicuous markinqs. Adult size unknown.

Geographical Distribution:
Known only from the type locality (near Misaki, Japan).

Habitat and Biology:
Almost totally unknown, inhabits deep water, probably near the bottom.

Size:
Maximum over 37.5 cm, but adult size unknown.

Interest to Fisheries:
None.

Remarks:
Data from Nakaya (1975); this species was not examined by the writer. There are somewhat similar long-nosed Apristurus from off Australia and New Zealand, but these among other things differ from this species and all other members of the genus in having much longer, narrower, almost Mitsukurina-like snouts. At least one and possibly two new species may be represented.

Type material:
Holotype: Hokkaido University Laboratory of Marine Zoology, HUMZ 42399, 375 mm immature male. Type Locality: 33° 13'N, 133° 44'E, Tosa Bay, Kochi Prefecture, Honshu, Japan, western Pacific.

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