Whitespotted Bullhead Shark

fieldmarks: Dorsal fins with spines, anal fin present, colour pattern of white spots on variegated darker background including dark saddles in adults, hatchling young with whorls of dark lines on a light background. Supraorbital ridges moderately high, abruptly truncated posteriorly; interorbital space moderately concave, depth between ridges about half 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 20 to 26% and anal-caudal space 8 to 10% of total length. Lateral trunk denticles large and rough. Propterygium separate, not fused to mesopterygium. First dorsal-fin spine directed somewhat forward in hatchlings and juveniles and vertical in adults; first dorsal-fin origin far anterior to pectoral-fin insertions, just behind or even over pectoral-fin origins and over third to fifth gill openings; first dorsal-fin insertion far anterior to pelvic-fin origins, just behind pectoral-fin insertions; first dorsal-fin free rear tip anterior to or opposite of pelvic-fin origins; first dorsal fin falcate in young and high and semifalcate in adults, first dorsal-fin height 11 to 21% of total length, first dorsal fin much larger than pelvic fins; second dorsal-fin origin over pelvic-fin inner margins and well in front of pelvic-fin rear tips, second dorsal fin falcate and much smaller than first dorsal fin. Anal fin angular and falcate, apex slightly anterior to lower caudal-fin origin when laid back; anal-caudal space slightly less than twice anal-fin base. Total vertebral count 104 to 116, precaudal count 67 to 73, monospondylous precaudal count 32 to 34, diplospondylous precaudal count 34 to 40, pre-first dorsal-fin spine count 10 to 14, and count from diplospondylous transition to second dorsal-fin spine 7 to 10. Egg cases unknown. A moderately large species, mature between 60 and 83 cm. Background colour of dorsal surface dark reddish brown with white spots, lighter in hatchlings, without a dark harness pattern but with darker indistinct saddles; head without light-coloured bar on interorbital surface of head in adults but young with transverse parallel dark lines there, and a series of narrow dark parallel stripes under eye in hatchlings, changing to a dusky patch in larger juveniles and lost in adults; fins without abrupt dark tips and white dorsal-fin apices; hatchlings with a unique and striking pattern of numerous thin curved parallel dark lines in whorls on fins and body, lost with growth and absent in adults.

Western and northern Indian Ocean, South Africa (KwaZulu-Natal), south-central Mozambique, Somalia, eastern shore of the Arabian Peninsula and southern Oman.

Maximum about 83 cm; hatchling 18 cm; males immature at 39 cm, adolescent at 56 cm, adults to at least 69 cm; adult females 75 to 83 cm.

A rare and little-known benthic shark of the outer continental shelf and uppermost slope of southern and East Africa and the eastern Arabian Peninsula.Unusual for the family in being a deepish water species found at 40 to 275 m, with most records below 100mand from trawler hauls. At least one station that recorded this shark was on sandy bottom. Presumably oviparous, but egg cases have not been reported to date. Young individuals including a hatchling have been found off southern Mozambique at 110 m. Crabs were found in the stomachs of two individuals.

Interest to fisheries none, occasionally caught as bycatch of commercial bottom trawlers including shrimp trawlers off southern Mozambique and South Africa. Conservation Status : Conservation status unknown, apparently rare or uncommon, only one specimen caught recently in experimental trawling off Mozambique (Sea Fisheries Research Institute, R.V. ALGOA cruise 014, 1994) with 52 offshore bottom trawl stations at depths of 37 to 517 m.