Author: Howell-Rivero, 1936
Two dorsal fins with ungrooved large spines, first dorsal spine origin in front of pectoral rear tips, first dorsal spine about as long as dorsal fin base, pectoral fins falcate and with angular free rear tips and deeply concave posterior margins, no white spots on sides, oblique-cusped cutting teeth in both jaws, no subterminal notch on caudal fin, no anal fin, and upper precaudal pit and lateral keels on caudal peduncle.
Body fairly slender. Snout subangular, slightly pointed, fairly broad, and moderately long, diagonal distance from snout tip to excurrent aperture of nostril much less than that from excurrent aperture to upper labial furrow, preoral snout about 1.3 to 1.4 times mouth width, preorbital snout less than twice as long as eye length; eyes considerably closer to snout tip than first gill slit; nostrils much closer to snout tip than mouth; anterior nasal flap with a small posterior secondary lobe, much narrower than space between its base and inner end of nostril. First dorsal spine long, nearly equal to fin base and with tip reaching nearly to apex of fin; second long, about as high as fin, and less than 6% of total length; first dorsal fin anteriorly situated, with fin origin just behind pectoral insertions and spine origin over their inner margins and well in front of their rear tips; first dorsal moderately high, height about half length from origin to rear tip; second dorsal markedly smaller than first, with height less than 6% of total length; pectoral fins fairly wide but strongly falcate, posterior margins deeply concave, rear tips angular and pointed; pelvic midbases about equidistant between first and second dorsal bases; caudal fin narrow-lobed and moderately long, with a long ventral lobe and strongly notched postventral margin. Precaudal pits well-developed. Lateral trunk denticles small, lanceolate and unicuspidate in adults. Colour: grey above, lighter below, without spots, dorsal fins with black tips and pectorals, pelvics and caudal with white edges. Size moderate, usually less than 1 m.
Western Atlantic: North Carolina to Florida (USA), Cuba, Hispanola, northern Gulf of Mexico (Mexico to Florida); southern Brazil, Argentina.
Habitat and Biology:
A common offshore warm-temperate and tropical 1 shark of the outer continental shelf and uppermost slopes, foundon or near the bottom in large, dense schools at depths between 60 and 380 m; young occur in shallower water than adults. Ovoviviparous, number of young about 10 per litter. ' Has an unusual huge isopod parasite that lives in its buccal cavity. Probably eats S bottom fishes and invertebrates.
Maximum total length possibly to 110 cm, common to 75 cm and, maturing at 50 cm or less.
Interest to Fisheries:
Taken in commercial bottom trawls primarily in the northern Gulf of Mexico and fished for its liver, which yields oil and vitamins. Seldom utilized for food.
Holotype: Museum of Comparative Zoology, Harvard, MCZ 1458, 524 mm adult male. Type Locality: Havana, Cuba.