Apristurus atlanticus

Author: (Koefoed, 1932)

Field Marks:
An Apristurus with unusually large eyes, 5% of total length.

Diagnostic Features:
Body rather slender, trunk slightly tapering toward head. Snout moderately long, and broad, preoral snout about 9% of total length; gill slits of moderate size, about half the eye length; gill septa incised but not pleated, without projecting medial lobes; eyes rather large, about 5% of total length; mouth probably short and broadly arched, with dental bands moderately expanded and with lower ones falling well behind uppers: mouth and labial furrows about under eyes; labial folds possibly little enlarged, with lower folds diagonal to body axis; mouth and teeth enlarged in males. Interdorsal space about 1.6 times first dorsal base, slightly less than preorbital snout; first dorsal fin slightly smaller in area than second, bases about equally long; origin of first dorsal about opposite last fourth of pelvic bases; second dorsal insertion about opposite 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 short, slightly less than preorbital length and about 10% of total length; pelvic fins moderately high and angular; anal fin short, fairly low, and angular, about 3.5 times as long as high, its base about equal to prespiracular space and 14% of total length; caudal fin fairly long and narrow, presence or absence of supracaudal crest uncertain (see remarks). Lateral trunk denticles of body may have elevated crowns, giving the skin a feltlike or fuzzy texture. Colour brown, with conspicuous dark posterior margins on precaudal fin and dark gill septa. Adult size uncertain.

Geographical Distribution:
Known with certainty only from the type locality.

Habitat and Biology:
A poorly known deepwater catshark, trawled from yellow mud bottom of the Atlantic continental slope.

Size:
Maximum known 25+ cm.

Interest to Fisheries: None.

Remarks:
This species is recognized following Springer (1979). but its validity needs to be confirmed by collection of more material. The writer examined several specimens of a small Apristurus in the Institut fur Seefischerei, Hamburg ichthyological collections, from very deep water (usually 1500 m or more) on offshore banks in the northeastern Atlantic north of the British Isles. Their most striking characters are their lead-grey coloration, elevated, Deania-like lateral trunk denticles that give their skin a fuzzy texture, relatively large eyes (nearly 4% of total length in adults), slender bodies, relatively narrow snguts, small nostrils with the internarial at least 1.5 times the nostril width, large, equal-sized dorsal fins with a short interdorsal space hardly longer than the first dorsal base, and relatively small size (adults being between 40 and 50 cm long. These may belong to the present species or a new one. If distinct, A. atlanticus apparently differs from them in having a more posterior first dorsal fin origin, darker coloration, and mouth not expanded anterior to eyes.

Type material:
Holotype: Zoological Museum, ZMO, about 250 mm total length. Type Locality: 28°08'N, 13°35'W, 1365 m depth off Canary Islands.

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