Dusky smooth-hound fishes is their ability to continually replace the teeth in their upper and lower jaws. Smooth dogfish differ from other sharks because of their 10 rows of flat, blunt teeth. The teeth in the upper and lower jaws are similar in size and are asymmetrical with rounded cusps. These teeth are used to crush and grind food, rather than bite it. Their unique dentition is important for their crustacean-based diet. In smooth dogfish, tooth replacement is related to body growth. They grow about 10 cm per every six rows of teeth replaced. That is an increase of 0.03 mm per
Narrownose smooth-hound Narrownose smooth-hound The narrownose smooth-hound ("Mustelus schmitti") is a houndshark of the family Triakidae. It is found on the continental shelves of the subtropical southwest Atlantic, from southern Brazil to northern Argentina, between latitudes 30° S and 44° S, at depths between 60 m to 195 m. It can reach a length of 74 centimeters. Narrownose smooth-hounds feed on crabs and probably other crustaceans, and presumably small fishes. Narrownose smooth-hounds are also caught and utilized for human consumption. The reproduction of this houndshark is Ovoviviparous, with 2 to 7 pups per litter, and a birth length of about 26 cm.