Author: (Springer, 1979)
Field Marks:
A slender, very small-eyed Apristurus with very large gill slits, a broad internarial and small nostrils, an extremely large, anteriorly expanded mouth, first dorsal origin about over pelvic midbases, an anal fin between 3 and 4 times as long as high, dark coloration with no conspicuous markings, and a long, low caudal fin with a prominent dorsal crest of denticles.
Diagnostic Features:
Body relatively slender, trunk slightly tapering toward head. Snout moderately long, broad, bell-shaped, and slightly pointed, preoral snout about 5 to 8% of total length; gill slits very large, somewhat greater than eye length; gill septa without projecting medial lobes or pleats and apparently not incised; eyes rather small, between 2 and 3% of total length; nostrils narrow, their width about 1.8 times in internarial space; mouth long, large, and broadly arched, with dental bands prominently expanded and with lower ones falling well behind uppers; mouth and labial furrows extending well in front of eyes; labial folds somewhat enlarged, with lower nearly transverse to body axis. Interdorsal space nearly or quite twice the first dorsal base, slightly less than preorbital snout; first dorsal fin slightly smaller than second, base of first about 3/4 the length of second; origin of first dorsal about over pelvic midbases; second dorsal insertion behind anal insertion; pectoral fins rather small, anterior margins about 6 to 13% of total length; inner margins long, nearly length of pectoral bases; interspace between pectoral and pelvic bases moderately long, slightly less or greater than prespiracular length and about 10 to 13% of total length; pelvic fins high and angular; anal fin short, fairly high, and rounded, between 3 and 4 times as long as high, its base about equal to prespiracular space and 10 to 15% of total length; caudal fin very long and narrow (in young at least), a well-developed crest of enlarged denticles on dorsal caudal margin. Lateral trunk denticles of body with crowns unicuspid, needle-like, and wide-spaced, surface probably with a feltlike or fuzzy texture. Colour blackish, without conspicuous markings on fins. Adult size unknown.
Geographical Distribution:
Eastern North Pacific: Pacific Panama from Gulf of Panama and Panama Bay.
Habitat and Biology:
A poorly known shark of the eastern Pacific continental slope, found at 915 to 975 m depth.
Size:
Maximum over 23 cm; males may mature at or above 20.8 cm total length.
Interest to Fisheries:
None.
Remarks:
The account of this species is based on Springer (1979). This shark is close to A. kampae but apparently distinguishable from it by several characters (see key to species). It also closely resembles an Apristurus known from adult sharks taken off the Galapagos Islands and Peru. These also have a dorsal crest of denticles and might be conspecific with A. stenseni, but differ in having smaller gills and larger eyes, a short, broader caudal fin, a less anteriorly expanded mouth, and a more domed head. They may also represent a new species.
Springer (1979) placed this species in the genus Parmaturus, subgenus Compagnoia, along with his new P. manis. These are transferred to Apristurus (see remarks under genus Apristurus).
Type material:
Holotype: Universitetets Zoologiske Museum, Copenhagen, Denmark, ZMK Galathea 739-1, 185 mm immature male. Type Locality: 07°22'N, 79°32'W, Gulf of Panama, eastern North Pacific, 915 to 975 m.