Oxynotus centrina

Author: (Linnaeus, 1758)

Field Marks:
Short, blunt snout, high, sail-like dorsal fins with spines, no anal fin, first dorsal spine inclined forwardy high, thick, triangular body with large, rough denticles, massive knobs on supraorbital ridges, vertically elongated spiracles, lanceolate upper teeth, lower bladelike teeth in less than 12 rows, colour pattern of darker marks on a light background.

Diagnostic Features:
Spiracle large and vertically elongated, crescent or oval in shape. Supraorbital ridges enlarged over eyes, with a knoblike posterior expansion studded with large denticles and ending in front of spiracles. Apices of dorsal fins broadly trianqular, nnstf!rinr maroins shallowiv concave; first dorsal spine inclined forward. Colour grey or grey-brown above and below, with darker blotches on head and sides; a light horizontal line separates dark areas on head and another crosses cheeks below eyes.

Geographical Distribution:
Eastern Atlantic: Bay of Biscay and Mediterranean Sea to Senegal, north apparently as a stray to Cornwall, England; also possibly from Liberia to Nigeria, Gabon to Namibia, and South Africa.

Habitat and Biology:
An uncommon, little-known bottom shark of the continental shelf and upper slope at depths of 60 to 660 m. Ovoviviparous, litters probably of 7 or 8 young. Eats polychaetes.

Size:
Maximum total length about 150 cm, but most individuals smaller; maturinu at about 50 cm.

Interest to Fisheries:
Caught in bottom and pelagic trawls and utilized for fishmeal, oil, and smoked and dried salted for human consumption. Apparently not abundant and mainly a minor byeatch of large offshore trawler fleets.

Remarks:
Bass, d'Aubrey and Kistnasamy (1976) noted that the Oxynotus recorded as O. centrina from Angola, Namibia, and South Africa may not be that species but an undescribed one, differing from O. centrina in having a much shorter interdorsal space. If this is correct, the records of O. centrina from tropical West Africa need to be reexamined, but until the problem is resolved the southern and southwestern African Oxynotus is retained in O. centrina.

Type material:
Holotype: Unknown. Type Locality: "Mare Mediterraneo".

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