Sarkastodon is an extinct genus of placental mammals from extinct subfamily Oxyaeninae within extinct family Oxyaenidae, that lived in Asia during the middle Eocene. It was a genus of large, carnivorous animals known only from a skull and jawbones. Sarkastodon was probably a hypercarnivore that preyed on large mammals in its range during the Middle Eocene, such as brontotheres, chalicotheres, and rhinoceroses. Its weight is estimated at 800 kg (1,800 lb), and its length at 3 m (10 ft).
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 Hyenodonts, 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.
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.
Dissacus is a genus of extinct carnivorous jackal to coyote-sized mammals within the family Mesonychidae, an early group of hoofed mammals that evolved into hunters and omnivores. Their fossils are found in Paleocene to Early Eocene aged strata in France, Asia and southwest North America, from 66 to 50.3 mya, existing for approximately 15.7 million years.
Tritemnodon was an extinct genus of placental mammals from extinct order Hyaenodonta, that lived in North America during the early Eocene. Fossils of Tritemnodon agilis have been found in Utah and Wyoming. It was the size of a wolf.
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.
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 sabre-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.
Systemodon is a genus of early Eocene mammal of Wasatchian age. It was one of many mammals originally considered the earliest horses, long classified in the genus Hyracotherium. These were dog-sized animals that in life would have looked vaguely like a paca, mara, or chevrotain The type species, S. tapirinus, is represented by 24 individuals from a locale called the Castillo pocket in the Huerfano Formation of Colorado. This well-preserved deposit allows researchers to reconstruct aspects of the environment and lifestyle of the species.
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.
