Triakis megalopterus

Author: (Smith, 1849)

Field Marks:
A very stout houndshark with a short, broadly rounded snout, lobate anterior nasal flaps that do not reach the mouth and are far separated from each other, long upper labial furrows that reach the lower symphysis of the mouth, semimolariform teeth with straight erect cusps and cusplets little-developed or absent, broad large fins with the pectorals broadly falcate and the first dorsal fin with a vertical posterior margin, and often black spots.

Diagnostic Features:
Teeth with strong erect cusps on at least the middle two-thirds of the dental band but often not well developed on more distal teeth, cusplets low or absent on almost all teeth, semimolariform but not bladelike. First dorsal fin with shrilntiv vertical Dosterior marain: Dectoral fins broadly falcate in adults. Total vertebral counts 162 to 166. Body with a few to numerous small black spots, few or absent in young, often numerous in adults although plain adults have been recorded.

Geographical Distribution:
Eastern South Atlantic and western Indian Ocean: South Africa (Cape coast, rarely northeast to Natal).

Habitat and Biology:
A common but little-known inshore bottom-dwelling shark of temperate continental waters, found often in shallow water up to the surfline. It prefers sandy shores and rocks and crevices in shallow bays. During summertime this shark congregates in schools, particularly in False Bay, western Cape, South Africa, which may have many pregnant females.

The sharptooth houndshark is hardy and keeps well in captivity. Observations by the writer of healthy individuals in a large circular tank at the Port Elizabeth Oceanarium, South Africa, shows them to be very active, mostly bottom swimmers, that are usually seen patrolling in irregular patterns close to the bottom in open, flat areas, often with a centimetre or less between the shark's underside and the substrate; they sometimes swim in midwater, but often close to the sides of the tank rather than in the open areas favoured by tope sharks, Galeorhinus galeus, in the same tank.

Ovoviviparous, without a yolk-sac placenta; number of young 6 to 12 per litter.

Eats crabs, bony fishes and small sharks (one had eaten a Scyliorhinus capensis).

Size:
Maximum to at least 174 cm; males adolescent at 94 to 130 cm and adult at 140 to 142 cm or more; females maturing between 140 and 150 cm, with adults reported at 140 to 174 cm; size at birth about 30 to 32 cm.

Interest to Fisheries:
Very commonly caught by rock and surf sports anglers, but not eaten much although perfectly edible. There is a fairly large commercial shark fishery in Gans Bay in South Africa that probably takes this species along with others; the meat of such sharks is dried into shark 'biltong' or jerky, which sells for a relatively high price.

Remarks:
Placement and synonymy of this species follows Compagno (1973c, 1979), Heemstra (1973), and Bass, D'Aubrey and Kistnasamy (1975b). Bass, D'Aubrey and Kistnasamy (1975b) recognized Triakis natalensis as a separate species based on its better developed cusplets on its teeth and plain coloration, but examination of material of T. megalopterus in the J.L.B. Smith Institute of Ichthyology confirmed the writer's earlier opinion (Compagno, 1979), that the two are synonyms. The characters of natalensis are apparently best considered as juvenile ones within a species, and that as these sharks grow they tend to loose cusplets and even cusps on some replacement teeth and gradually become spotted with black (some adults may retain a plain coloration).

Type material:
Holotype: ? Type Locality: Cape of Good Hope, South Africa.

%LABEL% (%SOURCE%)