Sphyrnidae
by J. C. Quero
Medium to large sharks. Front of head much flattened dorsoventrally and very widely expanded laterally, with the eyes at outer edges; lower eyelids with well-developed nictitating membrane; nostrils entirely separate from mouth, their anterior margin without barbels; teeth with only one cusp. Two dorsal fins, the base of the first anterior to origin of pelvic fins, the first dorsal fin much larger than the second; anal fin present; caudal fin asymmetrical, much shorter than half length of fish, with wellmarked sub-terminal notches; no pre-caudal keel.
Epipelagic, occurring in tropical to warm temperate surface waters of all oceans, mostly in shallow waters and entering enclosed bays and estuaries. The larger species are sometimes semi-oceanic over continental and insular shelves. Feeding voraciously on a wide range of fishes, sharks, rays and bottom-living invertebrates. Viviparous, the development with a yolk-sac placenta in at least some species.
Genera 2; in Clofnam area 1.
Recent revisions: Fraser-Brunner (1950), Tortonese (1950), Gilbert (1967), Springer (1977), Compagno (1979, 1981 and in press), Cadenat and Blache (1981).