Humpback smooth-hound the lower ones. The teeth have a main pointed cusp and sometimes smaller subsidiary ones. The first dorsal fin is approximately triangular and the trailing edge is fringed with bare, dark-coloured collagen rods known as ceratotrichia. The pectoral fins are large and the pelvic fins moderately so. The caudal peduncle is short and the lower lobe of the tail fin is hardly curved in adults. The colour of this shark is plain grey or greyish-brown without any spots or barring. The humpback smooth-hound is found in the eastern Pacific Ocean off the coast of Peru and Chile, between 1°N and
Humpback smooth-hound 45°S. Its depth range is between but it is most common between . It is found near the seabed, often on rocky shores, where it feeds on small fish and crustaceans such as crabs and mantis shrimps. It is viviparous and the females bear litters of five to ten young which are about long when born. The humpback smooth-hound is fished for human consumption in Chile but more particularly in Peru, where it is more common. Along with the spotted houndshark ("Triakis maculata") and the speckled smooth-hound ("Mustelus mento") it is known as "tollo" in its local fisheries, and of