Orcinus

Orcinus is a genus of four species of oceanic dolphins: "O. orca" (the killer whale), the only extant species, and the three extinct species "O. paleorca", "O. citoniensis" and "O. meyeri". 
"Orcinus" was once classified in the subfamily Orcininae, but this is no longer supported. The other members of Orcininae were moved to Globicephalinae, and the relation of "Orcinus" with other dolphins is unknown.