Creodonta is a former order of extinct carnivorous placental mammals that lived from the early Paleocene to the late Miocene epochs in North America, Europe, Asia and Africa. Originally thought to be a single group of animals ancestral to the modern Carnivora, this order is now usually considered a polyphyletic assemblage of two different groups, the oxyaenids and the hyaenodonts, not a natural group. Oxyaenids are first known from the Palaeocene of North America, while hyaenodonts hail from the Palaeocene of Africa.
Oxyaenidae is a family of extinct carnivorous placental mammals. Traditionally classified in order Creodonta, this group is now classified in its own order Oxyaenodonta within clade Pan-Carnivora in mirorder Ferae. The group contains four subfamilies comprising fourteen genera. Oxyaenids were the first to appear during the late Paleocene in North America, while smaller radiations of oxyaenids in Europe and Asia occurred during the Eocene.
Palaeoryctes is an extinct paraphyletic genus of mammals from paraphyletic subfamily Palaeoryctinae within family Palaeoryctidae, that lived in North America and Africa from middle Paleocene to early Eocene.
Machaeroides ("dagger-like") is an extinct genus of sabre-toothed predatory placental mammals from extinct subfamily Machaeroidinae within extinct family Oxyaenidae, that lived in North America (Wyoming) from the early to middle Eocene.
Pachyaena was a genus of heavily built, relatively short-legged mesonychids, early Cenozoic mammals that evolved before the origin of either modern hoofed animals or carnivores, and combined characteristics similar to both. The genus likely originated from Asia and spread to Europe, and from there to North America across a land bridge in what is now the North Atlantic ocean. Various described species of Pachyaena ranged in size from a coyote to a bear. However, recent work indicates that Pachyaena is paraphyletic, with P. ossifraga being closer to Synoplotherium, Harpagolestes and Mesonyx than to P. gigantea.
Sinopa is an extinct genus of placental mammals from extinct family Sinopidae within extinct order Hyaenodonta, that lived in North America and Asia from the early to middle Eocene.
Palaeonictis is an extinct genus of placental mammals from extinct subfamily Palaeonictinae within extinct family Oxyaenidae, that lived in Europe and North America from the late Paleocene to the early Eocene.
The Willwood Formation is a sedimentary sequence deposited during the late Paleocene to early Eocene, or Clarkforkian, Wasatchian and Bridgerian in the NALMA classification.
Galecyon ("polecat-dog") is an extinct genus of placental mammals from extinct order Hyaenodonta, that lived in Europe and North America during the early Eocene.
Pyrocyon is an extinct genus of small carnivorous placental mammals from extinct order Hyaenodonta, that lived in North America during the early Eocene. Fossils of Pyrocyon have been found in Wyoming and Colorado. Weight of Pyrocyon dioctetus has been estimated at around 2.6 kilograms.
Hyaenodonta is an extinct order of hypercarnivorous placental mammals of clade Pan-Carnivora from mirorder Ferae. Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe and persisted well into the late Miocene.
Prolimnocyon is an extinct paraphyletic genus of limnocyonid hyaenodonts that lived in Asia and North America during the late Paleocene to middle Eocene. Prolimnocyon chowi is the earliest known member of the hyaenodontid family Limnocyonidae.
Tytthaena is an extinct genus of placental mammals from extinct subfamily Tytthaeninae within extinct family Oxyaenidae, that lived in North America from the late Paleocene to early Eocene.
Machaeroidinae ("dagger-like") is an extinct subfamily of carnivorous saber-toothed placental mammals from extinct family Oxyaenidae, that lived from the early to middle Eocene of Asia and North America. Traditionally classified as hyaenodonts, this group is now classified as a member of the family Oxyaenidae.
Wyonycteris is a genus of small mammals that existed in the late Paleocene and early Eocene epochs. The type species is Wyonycteris chalix, which lived in Wyoming during the Clarkforkian North American Land Mammal Age of the Paleocene and was originally proposed to be an early form of insectivorous bat. Later re-examination of the material has put this alliance in doubt, and the genus has instead been proposed as belonging to the subfamily Placentidentinae, within the family Nyctitheriidae. Similar fossil material of the same time period found in Europe was later discovered and described as new species, Wyonycteris richardi.
Azygonyx was a small tillodont mammal, likely the size of a cat to raccoon, that lived in North America during the Paleocene and Eocene in the early part of the Cenozoic Era. The only fossils that have been recovered are from the Willwood and Fort Union Formations in the Bighorn Basin of Wyoming, United States, and date to the Clarkforkian to Wasatchian, about 56 to 50 million years ago. Fifty-six collections that have been recovered thus far include the remains of Azygonyx. Azygonyx survived the Paleocene Eocene Thermal Maximum along with other mammals like Phenacodus and Ectocion, both of which were ground-dwelling mammals. Azygonyx probably was a generalist terrestrial mammal that may have roamed around the ground, but was also capable of climbing trees.
Oxyaeninae is an extinct subfamily of placental mammals from extinct family Oxyaenidae, that lived in Asia, North America and Europe from the late Paleocene to middle Eocene.
Limnocyoninae is a subfamily of extinct predatory mammals from extinct order Hyaenodonta. Fossil remains of these mammals are known from late Paleocene to late Eocene deposits in North America and Asia. Limnocyonines had only two molars in the upper and lower dentition.
Palaeonictinae is an extinct subfamily of placental mammals from extinct family Oxyaenidae, that lived from the late Paleocene to early Eocene of Europe and North America.
Didelphodus is an extinct genus of eutherian mammal that inhabited North America and Europe during the Eocene epoch. It was insectivorous.
