Author: Tanaka, 1912
Field Marks:
Short snout, tremendously elongated anterior nasal flaps, no anal fin, stout fin spines on both dorsals, low, bladelike cutting teeth in both jaws, very stout body.
Diagnostic Features:
Anterior nasal flaps greatly elongated, expanded as long, prominent barbels that reach mouth; snout flattened, short, and broadly rounded, length less than 1/3 head length and much less than distance from mouth to pectoral origins; gill openings moderately broad and about equally wide; lips thin, not pleated or suctorial teeth similar in both jaws, bladelike, interlocked, with a single oblique cusp and distal blade on a low crown and root, upper teeth slightly smaller than lowers, edges smooth; tooth rows 26 or 27/22 or 26. Both dorsal fins with long, stout, ungrooved spines; first dorsal origin just behind free rear tips of pectoral fins, insertion well in front of pelvic origins and slightly closer to pectoral bases than pelvics; second dorsal origin about over free rear tips of pelvics; second dorsal fin about as large as first, base about equally long; pectoral fins with short, narrowly rounded free rear tips, not broadly lobate or acute and attenuated; caudal fin asymmetrical, not paddle-shaped, upper lobe long, lower lobe rather short but present, subterminal notch absent or very weak. No precaudal pits but lateral keels present on caudal peduncle. Dermal denticles with low, pedicellate, tricusped and triridged flat crowns. Cloaca without a luminous gland. Colour grey-brown above, whitish below, fins with conspicuous white margins.
Geographical Distribution:
Western Pacific: Japan (southeastern Honshu), New Zealand, Australia (New South Wales), Torres Island.
Habitat and Biology:
A little-known, easily recognized, bizarre dogfish of the uppermost continental and insular slopes, and probably the outer continental-insular shelves, of the western Pacific at depths of 360 to 494 m depth on or near the bottom. Ovoviviparous, number of young per litter 10 in one female (5 per uterus), size at birth not known. Food not known, but probably mostly bottom fishes with some invertebrates as in well-known species of Squalus. The tremendous, mandarin-like nasal barbels of this shark suggest that it may have enhanced sensory capacities in its barbels (presumably chemosensory), and that it trails them over the substrate like sturgeon or catfish to locate prey.
Size:
Maximum 122 cm, adults males about 86 cm, females mature above 92 to 108 cm reaching at least 122 cm.
Interest to Fisheries:
None at present. Garrick and Paul (1971a) note that this dogfish has a liver with a high squalene content but no Vitamin A, as in other deepwater sharks. In comparison the inshore Squalus acanthias has a high Vitamin A content and very low squalene, and the outer shelf S. "blainvillei" (= S. cf. mitsukurii) has a lower Vitamin A content and somewhat higher squalene content.
Type material:
Holotype: Science College Museum, Tokyo, 3397, 855 mm adult male. Type Locality: Southeastern Honshu.