Crested Bullhead Shark

fieldmarks: Dorsal fins with spines, anal fin present, supraorbital ridges greatly enlarged, colour pattern of dark broad bands on head, back and tail. Supraorbital ridges very high, more prominent than in any other Heterodontus, abruptly truncated posteriorly; interorbital space deeply concave, depth between ridges about equal to eye length. Anterior holding teeth with a cusp and a pair of cusplets in adults, posterior molariform teeth strongly carinate and not greatly expanded and rounded. Pre-first dorsal-fin length 22 to 28%, and anal-caudal space 5 to 8%, of total length. Lateral trunk denticles fairly large and rough. Propterygium separate, not fused to mesopterygium. First dorsal-fin spine directed obliquely posterodorsally in adults; first dorsal-fin origin anterior to pectoral-fin insertions, slightly behind pectoral-fin midbases and well posterior to fifth gill openings; first dorsal-fin insertion well anterior to pelvic-fin origins and well behind pectoral-fin insertions; first dorsal-fin free rear tip about opposite to or slightly behind pelvic-fin origins; first dorsal fin moderately high and semifalcate or angular in adults, height 10.8 to 15.2% of total length, slightly larger than pelvic fins. Second dorsal-fin origin well in front of pelvic-fin rear tips, second dorsal fin somewhat falcate or angular and nearly as large as first dorsal fin. Anal fin subangular or rounded to weakly falcate, apex reaching lower caudal-fin origin when laid back; anal-caudal space between 1 and 2 times anal-fin base. Total vertebral count 106 to 108, precaudal count 71 or 72, monospondylous precaudal count 34 or 35, diplospondylous precaudal count 36 to 38, pre-first dorsal-fin spine count 16 to 18, and count from diplospondylous transition to second dorsal-fin spine 8 to 11. Egg cases with flat thin spiral flanges that are diagonal to case axis and a pair of long, slender tendrils on case apex, flanges with 6 or 7 turns. A large species, mature between 60 and 152 cm. Background colour of dorsal surface light brown or yellowish brown with five broad diffuse-edged brown or blackish saddles, but without light or dark spots; saddles not arranged in a harness pattern; head with a dark bar on interorbital surface and a single broad dark blotch under eye; fins without abrupt dark tips and white dorsal-fin apices; hatchlings without whorls on fins and body, colour pattern as in adults.

Western South Pacific: East coast of Australia, from southern Queensland and New South Wales, with a doubtful record from Tasmania, and a possible record from the top of the Cape York Peninsula.

Maximum said to be 152 cm long and attaining at least 130 cm, but most individuals are below 122 cm. Young hatch at about 17 cm. Males mature at about 60 cm and females at about 70 cm.

A moderately common benthic and epibenthic shark of the southern Australian continental shelf at moderate depths,ranging from close inshore in the intertidal zone to 93 m. Found on reefs, in kelp and in beds of seagrass. This shark often wedges its way between rocks in search of prey. The egg cases are dropped by females in seaweeds or sponges from 20 to 30 m depth on the bottom, during July and August, and hatch after about eight months. Eggs are commonest on the bottom in August and September but are found throughout the year. In captivity a newly hatched female matured and began to lay eggs at an age of 11.8 years and a length of about 70 cm. The crested bullhead shark feeds primarily on sea urchins (echinoids), but also crustaceans, molluscs and small fishes.

Interest to fisheries minimal, taken by bottom trawlers but not utilized commercially. Utilization by aquarium trade uncertain, but an obvious candidate because of its unusual appearance and striking colour pattern. Observed and photographed by divers, but not a special focus of ecotourism.