Author: Garman, 1906
Field Marks:
A deepwater, soft-bodied, plain catshark with a moderately short snout, first dorsal origin just behind pelvic origins, second dorsal about as large as first, crest of denticles on dorsal and preventral caudal margins.
Diagnostic Features:
Snout broadly rounded; nasal flaps large, narrow-based and lobate; gill septa not excavated and concave posteriorly. First dorsal fin about as large as second; first dorsal origin just behind pelvic origins; first dorsal insertion slightly behind pelvic insertions; second dorsal smaller than anal fin; second dorsal origin well behind anal origin; second dorsal insertion about over anal insertion; ventral edge of caudal peduncle and preventral caudal margin with a crest of enlarged denticles.
Geographical Distribution:
Western North Pacific: Japan (south eastern Honshu).
Habitat and Biology:
A little-known, but possibly common deepwater bottom-dwelling shark, on the continental slopes off Japan at 786 m depth (depth for the holotype, the only specimen for which this 2 was recorded). Has a high concentration of squalene in its liver, as in many deepwater squaloids.
Size:
Maximum at least 64 cm; males imiature at 56 cm; state of maturity uncertain for females 59 to 64 cm.
Interest to Fisheries:
Probably of minor importance in the past to some Japanese fishermen using deep-set longlines, but apparently seldom caught at present.
Remarks:
Synonymy follows Springer (1979), who examined the holotype (now lost) of Pristiurus hertwigi.
Type material:
Holotype: Museum of Comparative Zoology, Harvard, MCZ-1107, ca. 544 mm, immature male. Type Locality: Sagami Bay, Japan, 34°59'N, 139°31'E, 786 m depth.