Houndsharks, Triakidae, are a family of ground sharks, consisting of about 40 species in 9 genera. In some classifications, the family is split into two subfamilies, with Mustelus, Scylliogaleus, and Triakis in the subfamily Triakinae, and the remaining genera in the subfamily Galeorhininae.Houndsharks are distinguished by possessing two large spineless dorsal fins, an anal fin, and oval eyes with nictitating eyelids.