Author: Nakaya, 1975
Field Marks:
A large Galeus with an unusually short anal fin, long space between anal and pelvic bases, prenarial snout longer than the eyes, and, in males, slender, greatly elongated claspers.
Diagnostic Features:
Precaudal tail not noticeably compressed at base. Snout moderately long and pointed, preoral length about 7% of total length; prenarial snout greater than eye length; eyes probably nearly lateral, with subocular ridges obsolete; mouth fairly large and long, broadly arched, its width 6 to 8% of total length; labial furrows moderately long, not confined to mouth corners. Pelvic fins large, low, and angular; interspace between pelvic and anal bases considerably longer than anal base; anal base short, 8 to 10% of total length, much less than interdorsal space; its origin varying from below to behind midlength of interdorsal; no suboaudal crest of enlarged denticles on preventral caudal margin. A variegated colour pattern of obscure and poorly defined dark saddle blotches on body and caudal fin; dorsal and caudal fins without black tips; mouth lining light. Monospondylous precaudal centra 33 to 36. Size moderate, adults up to about 66 cm.
Geographical Distribution:
Western North Pacific: Southeastern Honshu, Japan.
Habitat and Biology:
A common, probably deepwater bottom shark of Japan. Oviparous, possibly with a single egg laid per oviduct. 3 There is an interesting sexual dimorphism in adults of this shark, the anal fins of males being about 2% of total length shorter than females, which 2 was thought by Nakaya (1975) to be related to the function of the unusually long claspers of this shark, which presumably need more 1 clearance of the anal fin than such species as G. eastmani and G. sauteri, which have much shorter claspers and lack the sexual dimorphism in anal length.
Size:
Adults maturing at about 53 to 55 cm; largest reported 65.6 cm.
Interest to Fisheries:
Not known.
Type material:
Holotype: Hokkaido University Laboratory of Marine Zoology, HUMZ 40012, 596 mm adult male. Type Locality: Mimase, Kochi Prefecture, Honshu, Japan.