by J.-C. Quero
Large sharks with fusiform bodies. Snout not very elongate, nostrils widely separated from mouth, without barbels; labial furrows at corners of jaws; eyelid without nictitating fold or membrane; teeth large and relatively few; spiracle present or absent; 5 gill openings, the fifth in front of origin of pectoral fin; gill arches without gillrakers. Two dorsal fins, the base of the first much shorter than caudal fin; the posterior end of base of the first dorsal fin far in advance of origin of pelvic fins; second dorsal fin and anal fin much smaller than first dorsal fin; caudal fin lunate, less than one-third of total length; caudal peduncle strongly depressed and expanded laterally, forming a prominent keel on each side, extending well back on to the caudal fin; upper and lower pre-caudal pits well developed.
Epipelagic or pelagic in whole or parts of temperate and tropical waters of all oceans; active, strong swimmers. Feeding mainly on a wide range of pelagic shoaling fish and squid; some species have a reputation as man-eaters. Some species ovoviviparous.
Genera 3; in Clofnam area 3.
Recent revisions: Bigelow & Schroeder (1948), Farquhar (1963), Garrick & Schultz (1963), Bass et al. (1975), Cadenat & Blache (1981), Compagno (1981 and in press).