Wikipedia
Xiphodontidae
Xiphodontidae is an extinct family of even-toed ungulates ( order Artiodactyla), endemic to Europe during the Eocene 40.4—33.9 million years ago, existing for about 7.5 million years. They were, most likely, all terrestrial herbivores. Paraxiphodon suggests that they survived into the Lower Oligocene, at least.