Speckled smooth-hound seabed on the continental shelf at depths of between . Reports of this fish occurring in the Atlantic Ocean off the coast of Argentina are thought to be erroneous, and are likely to refer to the narrownose smooth-hound ("Mustelus schmitti"), another shark that is speckled with white spots. The speckled smooth-hound is ovoviviparous with eggs that develop within the female and hatch into juvenile fish which are about at birth. Litter sizes are typically seven. Along with the humpback smooth-hound ("Mustelus whitneyi") and the spotted houndshark ("Triakis maculata"), this fish is known to local fisheries as "tollo" and is caught
Speckled smooth-hound peduncle is short and the lower lobe of the tail fin is narrow and slightly curved. The maximum length is about with maturity being reached by males at about and females at about . Adults are grey or greyish-brown above and paler below, liberally speckled with white spots. Juveniles have dark bars. The speckled smooth-hound is found off the Pacific coast of South America, including the Galapagos Islands and the Juan Fernández Islands. Its range extends from the Isla Lobos de Tierra in Peru to the southern tip of Chile. It is a demersal fish and swims close to the