They are relatively small sharks, rare time greater to 1.5 meters, being the females a little greater than the males. Longevos are individual enough being exemplary adults of 40 years of age. The external distinguishing characters are: a thin body, a head something flattened back-ventral and provided with a very prominent snout, very great and made oval eyes horizontally; the mouth curved with subtriangular and sharp teeth, arranged in many rows unlike other sharks that have them arranged in mosaics. Their five pairs of lateral branchial openings are well visible, the two last ones located over the base of the pectoral ones. The first dorsal fin is much more great that second and is located very in front of the ventrals; second one is to the height of the anal fin. The tail is heterocerca, with a very long lobe in the end of great volume. The body is of amarronado plomizo and gray gray color, without spots and target in all the ventral length. Its presence is registered in all the seas - mainly in the South hemisphere specially warm and subtropical. It is pelágico swimming assets, and coastal pelágico, reason why it is also captured with no need to be embarked. In the Argentine coasts good part of their diet constitutes pejerreyes, which indicates its restlessness to approach the coasts. Other organisms that serve to him as food are fish of bottom and average water like sardines, herrings, anchovies, merluzas, brótolas, corvinas and cephalopods like calamaries and pulpy. Also crabs, sprocket wheels, lobsters and moluscos have been in their stomachs. The reproductive cycle begins approximately to the 10 years of age in the males and to 13 or 14 in the females, that are ovovivíparas and develop between 2 and 50 embryos, every three years.