The false killer whale was first described by the British paleontologist and biologist Richard Owen in his 1846 book, A history of British fossil mammals and birds, based on a skull discovered in 1843. The skull was found in Stamford, Lincolnshire in England and dated to the Middle Pleistocene around 126,000 years ago.[1][4] He found the skull comparable to the long-finned pilot whale (Globicephala melas), the beluga whale (Delphinapterus leucas), and Risso's dolphin (Grampus griseus)–in fact, he gave it the nickname "thick toothed grampus" in light of this and assigned the animal to the genus Phocaena (a genus of porpoises) which Risso's dolphin was also assigned to in 1846. The species name crassidens means "thick toothed".[4]