Author: (Gilbert, 1895)
Field Marks:
A thick-bodied, thick-headed Apristurus with pleats and grooves on the branchial region, high rounded fins, and no caudal crest.
Diagnostic Features:
Body stout, trunk slightly tapering toward head. Snout moderately long and broadly rounded, preoral snout about 9% of total length; gill slits very small, much less than eye length; gill septa without projecting medial lobes and slightly incised, but covered with unique pleats and folds that extend above the gill slits and onto the throat; eyes rather small in adults, about 3% of total length; nostrils broad, their width about equal to internarial space; incurrent and excurrent apertures rather narrow and slitlike, anterior nasal flaps large and triangular; mouth long, large, and broadly arched, with dental bands prominently expanded and with lower ones falling far behind uppers; mouth and labial furrows extending well in front of eyes; labial folds enlarged, with lowers nearly transverse to body axis. Interdorsal space slightly greater than first dorsal base, slightly less than preorbital snout; first dorsal fin about as large as second, bases about equally long; origin of first dorsal slightly anterior to pelvic midbases; second dorsalinsertion behind anal insertion; pectoral fins rather small, anterior margins about 11% of total length; inner margins long, two-thirds length of pectoral bases; interspace between pectoral and pelvic bases short, slightly greater than preorbital length and about 11% of total length in adults; pelvic fins high and broadly rounded; anal fin short, high, and rounded, slightly more than twice as long as high, its base slightly greater than the prespiracular space and 13% of total length in adults; caudal fin moderately broad, without a dorsal crest of enlarged denticles. Lateral trunk denticles of body with crowns erect and fairly close-set, skin surface with a feltlike or fuzzy texture. Colour dark brown. without conspicuous markings on fins. Adults moderately large, adult female 50 cm.
Geographical Distribution:
Central Pacific: Hawaiian Islands. Western South Pacific: Banda Sea off southern Sulawesi.
Habitat and Biology:
A rare shark known from two specimens taken on the insular slopes, on or near the bottom at 572 to 1482 m depth. Probably oviparous; the holotype is a gravid female.
Size:
The holotype was adult at 50 cm.
Interest to Fisheries:
None.
Remarks:
The above diagnosis and illustration is based on the writer's examination ot tne hototype. Weber (1913) referred a 105 mm juvenile Apristurus from the Banda Sea to this species, which was accepted by Fowler (1941) and Springer (1979). The writer examined this specimen in the collections of the Zoölogisch Museum of Amsterdam (ZMA 111.403, Banda Sea, 5°40.7'5, 120°45.5'E, 1158 m depth). Although much smaller and slenderer than the holotype, it is generally similar and has the same unique pleated gills; and is placed in A. spongiceps despite the great distance between the two localities. Springer (1979) included this species in a separate genus, Parapristurus, but I follow Fowler (1941) and Bigelow and Schroeder (1948) in retaining it in Apristurus (see remarks under genus Apristurus for a discussion of this problem).
Type material:
Holotype: U.S. National Museum of Natural History, USNM 51590, 500 mm adult female. Type Locality: Central Pacific, near Bird Island, Hawaiian Islands, 572 to 1462 m depth.