Slender smooth-hound journal "Transactions of the Royal Society of New Zealand". Garrick named the species "Triakis attenuata", in reference to its extremely slender ("attenuate") body. In 1973, Leonard Compagno proposed a separate genus for the slender smooth-hound: "Gollum", after the character in J. R. R. Tolkien's "The Lord of the Rings", "to whom this shark bears some resemblance in form and habits." He placed "Gollum" with the finback catsharks (Proscylliidae), but also noted its many anatomical similarities to the false catshark ("Pseudotriakis microdon"). At the time, Compagno chose to maintain "Pseudotriakis" as the sole member of the family Pseudotriakidae because of its
Dusky smooth-hound and "canis" translates to dog. "M. canis" has an allopatric relationship with "M. mustelus" (common smooth-hound) and a sympatric relationship with "M. norrisi" (narrowfin smooth-hound). "M. canis" is found in marine and brackish waters and is demersal (bottom-dwelling) and oceanodromous (migratory in seas). They can be found between 42°N and 44°S and 100 and 46° W. "M. canis" in the North Atlantic migrates in response to changing temperature. In winter, they can be found in the Carolinas to the outlet of the Chesapeake Bay, and in summer from the mid-Atlantic to southern New England. They are most abundant on the