SHARKS

Carcharhiniformes: Sphyrnidae 499
4a. Anterior margin of head nearly straight in adults, moderately convex in young; prenarial
grooves hardly developed; teeth strongly serrated at all sizes; first dorsal fin markedly
falcate; second dorsal about a third as high as first dorsal fin, with a short inner margin;
posterior margins of second dorsal and pelvic fins deeply concave (Fig. 4) . . . . Sphyrna mokarran
4b. Anterior margin of head moderately convex in adults, strongly so in young; prenarial
grooves well developed; teeth smooth in young, weakly serrated in large individuals; first
dorsal fin erect or slightly falcate; second dorsal-fin less than a third the height of first dorsal
fin, with a long inner margin; posterior margins of second dorsal and pelvic fins slightly concave
to nearly straight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5a. Median indentation present on anterior margin of head; free rear tip of second dorsal fin
nearly reaching upper caudal-fin origin; anal-fin base noticeably larger than that of second
dorsal fin (Fig. 7). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sphyrna lewini
5b. Median indentation absent from anterior margin of head; free rear tip of second dorsal fin
well ahead of upper caudal-fin origin; anal-fin base about as large as that of second dorsal
fin (Fig. 8). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sphyrna zygaena
Fig. 7 Sphyrna lewini Fig. 8 Sphyrna zygaena
List of species occurring in the area
The symbol is given when species accounts are included.
Sphyrna lewini (Griffith and Smith, 1834).
Sphyrna media Springer, 1940.
Sphyrna mokarran (Rüppell, 1837).
Sphyrna tiburo (Linnaeus, 1758).
Sphyrna tudes (Valenciennes, 1822).
Sphyrna zygaena (Linnaeus, 1758).
References
Bigelow, H.B. and W.C. Schroeder. 1948. Sharks. In Fishes of the Western North Atlantic. Mem. Sears Fnd. Mar. Res.,
(1)1:56-576.
Compagno, L.J.V.and R.Vergara R.1978.Sphyrnidae.In FAO species identification sheets for fisheries purposes. Western
Central Atlantic, (Fishing Area 31), Volume V, edited by W. Fischer. Rome, FAO (unpaginated).
Compagno, L.J.V.1984.FAO Species Catalogue.Vol.4.Sharks of the World.An annotated and illustrated catalogue of shark
species known to date. FAO Fish. Synop. (125)Vol.4,Pt.2: 251-655.
Compagno, L.J.V. 1988. Sharks of the Order Carcharhiniformes. New Jersey, Princeton University Press, 572 p.
Gilbert, C.R. 1967. A revision of the hammerhead sharks (Family Sphyrnidae). Proc. U. S. Natn. Mus. 119:1-88.
Gilbert, C.R. 1967. A taxonomic synopsis of the hammerhead sharks (Family Sphyrnidae). In Sharks, Skates, and Rays,
edited by P. W. Gilbert, R.F. Mathewson, and D.P. Rall. Baltimore, Johns Hopkins Press, pp. 69-76.
McEachran, J.D.and J.D.Fechhelm.1998.Fishes of the Gulf of Mexico, vol. 1, Myxiniformes to Gasterosteiformes.Austin,
Texas, University of Texas Press, 1112 p.