Author: Gill, 1862
Diagnostic Features:
Body fairly stout. Head narrow and flattened but not trowel-shaped; snout acutely triangular or subtriangular in dorsoventral view and very long, with preoral length much greater than internarial space and mouth width; eyes extremely small, without posterior notches; spiracles absent; no papillose gillrakers on internal gill openings; nostrils small, internarial space about 3 times the nostril width; anterior nasal flaps vestigial, not tubular; labial furrows short but prominent, essentially confined to mouth corners, with uppers about equal to lowers and with their anterior ends falling far behind eyes; teeth not strongly differentiated in upper and lower jaws, anteroposteriors with more or less erect, narrow acute cusps, no cusplets, and proximal and distal blades; uppers with slightly broader flatter cusps and serrations; lowers with slenderer cusps and smooth edges; cusps of lower teeth not protruding when mouth is closed; 49 to 60/49 to 56 rows of teeth. Interdorsal ridge absent; no lateral keels on caudal peduncle; upper precaudal pit transverse and crescentic. First dorsal origin far forward, over midbase or second third of pectoral bases, its midbase much closer to pectoral bases than to pelvics and free rear tip well anterior to pelvic fin origins; second dorsal fin considerably smaller than first but rather large, its height about 1/2 of first dorsal height, its origin slightly anterior or opposite anal origin; pectoral fins broad and triangular, their lengths from origin to free rear tip about 3/4 of pectoral anterior margins; pectoral origins about under 5th gill slit; anal fin somewhat smaller than second dorsal, with preanal ridges very short and a deeply notched posterior margin. Colour grey or brownish above, without a colour pattern. Moderatesized sharks, adults probably not exceeding 1.6 m.
Remarks:
The genus Isogomphodon was until recently synonymized with Carcharhinus (see Bigelow and Schroeder, 1948; Garrick and Schultz, 1963; Garrick, 1967). However, Springer (1950) resurrected it and Compagno (1970, 1979) and Compagno and Vergara (1978) resurrected it a second time, and Compagno (1979) gave a taxonomic history of the genus and a detailed review of its relationships. Garrick (1982) excluded the single species included in Isogomphodon, Carcharias (Prionodon) oxyrhynchus Müller and Henle, 1839, from Carcharhinus.