Author: Müller and Henle, 1839
Field Marks:
Large sharks, with conical to slightly depressed, pointed snouts, long mouths extending behind eyes, small eyes without nictitating eyelids, moderately long gill openings, large teeth with slender cusps and lateral cusplets, small intermediate teeth separating anterior and lateral teeth in the upper jaw, two large dorsal fins and an anal fin, small pectoral fins, a compressed caudal peduncle without keels but with an upper precaudal pit, and an asymmetrical caudal fin with a strong but short ventral lobe.
Diagnostic Features:
Trunk compressed-cylindrical and moderately stout. Head short, much shorter than trunk, snout short to moderately long, pointed and conical to slightly depressed, not greatly elongated, flattened and bladelike; eyes small to moderately large; mouth large, ventral on head; gill openings moderately large, not extending onto dorsal surface of head, all anterior to pectoral fin bases; no gillrakers on internal gill slits; teeth large, anteriors narrow and awl-like but laterals moderately compressed and bladelike, less than 60 rows in either jaw; two or three rows of large anterior teeth on each side of upper jaw, three in lower, the uppers separated from the upper lateral teeth by one of five rows of small intermediate teeth or a gap. First dorsal fin large, moderately high, erect and angular; second dorsal and anal fins about as large as first dorsal or somewhat smaller, with broad, nonpivoting bases, pectoral fins moderately long and broad, much shorter than head ih adults; pelvic fins large, nearly or quite as large as first dorsal fin; caudal fin not lunate, upper lobe moderately long, less than half as long as rest of shark, lower lobe short but strong. Upper precaudal pit present, caudal peduncle compressed and without keels.
Habitat, Distribution and Biology:
Odontaspids are tropical to cool-temperate, inshore and deepwater sharks with a wide geographic distribution in virtually all seas, in continental and insular waters from the surf zone to the outer shelves and down the slopes to possibly 1600 m. All the known species are of large size (to at least 360 cm).
These sharks are relatively slow but active littoral and epibenthic swimmers. They feed on a wide variety of bony fishes, other sharks, rays, squids and bottom crustaceans. Development is ovoviviparous, without a yolk-sac placenta but with uterine cannibalism.
Sand tiger sharks are relatively inoffensive and usually unaggresive to humans in the water. Swimmers, divers, and fishermen commonly encounter inshore members of the family (genus Eugomphodus), but despite their impressive teeth there have been few attacks by these sharks on people. In some areas these sharks have a fearsome reputation as 'maneaters', but this is primarily a result of confusion with other species (especially with requiem sharks, family Carcharhinidae). As with other large sharks, the sand tigers should be regarded as potentially dangerous and should not be harassed or provoked underwater. Inshore sand tigers superficially resemble the carcharhinid lemon shark (Negaprion), which can be extremely aggressive when provoked.
Interest to Fisheries:
The species of Eugomphodus are important for inshore and offshore fisheries where they occur, while Odontaspis species are less so, being less abundant and less valuable than Eugomphodus species.
Remarks:
The arrangement of species and genera in this family follows revisionary work by the author. Reviews of this family include Bigelow and Schroeder (1948), d'Aubrey (1964), and Bass, d'Aubrey and Kistnasamy (1975b). Although most writers recognize only one genus of Odontaspididae, two genera are included here for the living species. This follows recent palaeontological work (for example, Glikman, 1964, 1967, Herman, 1975) that treats the taurus and ferox groups of species as separate genera, but also morphological studies on these species groups that revealed their distinctness (Compagno, unpub. data).
Gilmore, Dodrill and Linley (1983) give a detailed and fascinating account of the reproduction of the sand tiger shark, Eugomphodus taurus, documenting the squence of intrauterine nourishment in this species, in which a successful embryo progresses from using stored yolk through killing and eating other embryos to eating unfertilized eggs, for a 9 to 12 month gestation period.