Traditionally, otariids had been subdivided into the fur seal (Arctocephalinae) and sea lion (Otariinae) subfamilies, with the major distinction between them being the presence of a thick underfur layer in the former. Under this categorization, the fur seals comprised two genera: "Callorhinus" in the North Pacific with a single representative, the northern fur seal ("C. ursinus"), and eight species in the Southern Hemisphere under the genus "Arctocephalus"; while the sea lions comprise five species under five genera. Recent analyses of the genetic evidence suggests that "Callorhinus ursinus" is in fact more closely related to several sea lion species. Furthermore, many of the Otariinae appear to be more phylogenetically distinct than previously assumed; for example, the Japanese sea lion ("Zalophus japonicus") is now considered a separate species, rather than a subspecies of the California sea lion ("Zalophus californius"). In light of this evidence, the subfamily separation has been removed entirely and the family Otariidae has been organized into seven genera with 16 species and two subspecies.