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Characteristics, distribution and ecology
Taxonomische classification
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Author: (Maclay and Macleay, 1884)

Field Marks:
Dorsal fins with spines, anal fin present, first dorsal origin over pectoral bases, colour pattern of 12 broad, irregular-edged, dark saddle-marks on a light background.

Diagnostic Features:
Supraorbital ridges low, not abruptly ending behind eyes; molariform teeth in rear of mouth greatly expanded and rounded, without medial ridges. First dorsal origin over pectoral bases; apex of anal fin falling well short of lower caudal origin; anal base nearly or quite 2 times in space between anal base and lower caudal origin. Colour light brown with broad, dark brown saddle-marks. Egg cases with simple, flat, broad paired spiral flanges, diagonal to case axis and with 3 turns visible on sides, case apex with very short tendrils.

Geographical Distribution:
Western North Pacific: Off Japan, Korean Republic, northern China including Taiwan Island.

Habitat and Biology:
A common, temperate-water bullhead shark of the western North Pacific continental shelf, occurring at moderate depths of6 to 37 m, on or near the bottom. It prefers rocky and kelp-covered bottom.

This is a sluggish, slow-swimming shark, easily caught by divers. It slowly explores the bottom, swimming and 'walking' with its mobile paired fins.

Oviparous, laying its large spiral-cased eggs among rocks or in kelp, at depths of about 8 or 9 m; several females may lay their eggs in a single site, termed 'nests', although these apparently do not guard these sites after laying. In Japanese waters eggs are dropped from March through September, most abundantly in March through April; each female usually lays two eggs at a time, for 6 to 12 spawnings. Eggs hatch in about a year.

The Japanese bullhead shark feeds on crustaceans, molluscs (including top shells), small fishes and sea urchins. It can protrude its jaws a considerable distance while grabbing prey.

Size:
Maximum total length about 120 cm, males adult at 69 cm. Size at hatching about 18 cm.

Interest to Fisheries:
Probably minimal, caught and eaten in Japan and presumably elsewhere in its range.

Type material:
Holotype: Australian Museum, Sydney, female. Type Locality: Tokyo, Japan.

Japanese bullhead shark (Heterodontus japonicus)