Pseudorca yokoyamai

Pseudorca yokoyamai is an extinct species of oceanic dolphin from the Calabrian stage of the Pleistocene of Japan and a relative of the living false killer whale, Pseudorca crassidens. Hikoshichiro Matsumoto of Tohoku Imperial University described it in 1926. The holotype is two teeth, probably the last two in the jaw, found at Hommoku in Yokohama, which gave the species its name; a paratype is the right mandible with seven teeth from Kazusa Province on the opposite side of Tokyo Bay. The teeth are mostly conical and bend backward under a smooth enamel coat, and the last two of the holotype measure 47 and 50 millimetres in height. The animal had smaller but more numerous teeth than the false killer whale and may represent an intermediate stage between that species and the pilot whales of the genus Globicephala.