Eocene Artiodactyla

Andrewsarchus (), meaning "Andrews' ruler", is an extinct genus of artiodactyl that lived during the Middle Eocene in what is now China. The genus was first described by Henry Fairfield Osborn in 1924 with the type species A. mongoliensis based on a largely complete cranium. A second species, A. crassum, was described in 1977 based on teeth. A mandible, formerly described as Paratriisodon, does probably belong to Andrewsarchus as well. The genus has been historically placed in the families Mesonychidae or Arctocyonidae, or was considered to be a close relative of whales. It is now regarded as

Archaeotherium (, meaning "ancient beast") is an extinct genus of entelodont artiodactyl endemic to North America during the Eocene and Oligocene epochs (35–28 mya). Archaeotherium fossils are most common in the White River Formation of the Great Plains, but they have also been found in the John Day Basin of Oregon and the Trans-Pecos area of Texas. Archaeotherium's fossils come from North America, between the Priabonian and Rupelian stages of the Eocene and Oligocene (35–28 million years ago). Up to fifteen species of Archaeotherium have been identified, which are divided into three subgenera

Indohyus (meaning "Indian pig", from Greek ινδός, indos, meaning 'Indian' and ὗς, hus, meaning 'pig' or 'swine') is an extinct genus of raoellid artiodactyl known from Eocene fossils in Asia. The fossils were discovered among rocks that had been collected in 1970 in Kashmir by the Indian geologist A. Ranga Rao, who found a few teeth and parts of a jawbone. He named the type and only species, Indohyus indirae, one year later.

Protoceratidae is an extinct family of herbivorous North American artiodactyls (even-toed ungulates) that lived during the Eocene through Pliocene. While early members of the group were hornless, in later members males developed elaborate cranial ornamentation. They are variously allied with Ruminantia or Tylopoda.

Anthracotherium (from Ancient Greek ἄνθραξ (ánthrax), meaning "coal", and θηρίον (theríon), meaning "beast") is an extinct genus of anthracotheriid artiodactyls characterized by having 44 teeth, with five semi-crescentic cusps on the crowns of the upper molars. The genus ranged from the middle Eocene period until the early Miocene, having a distribution throughout Eurasia probably even reaching South East Asia (Kalimantan and West Timor). Material subjectively assigned to Anthracotherium from Pakistan suggests the last species died out soon after the start of the Miocene.

Raoellidae () is a family of extinct semiaquatic artiodactyls from the middle Eocene (early Lutetian) closely related to cetaceans. They are known primarily from northern India and Pakistan, especially in the Subathu Group of India, although potential remains of the raoellid Khirtharia have been found in northern China. They are relatively small animals; on average, raoellids were the size of a red fox. However, Khirtharia major, at about twice the size of an average-sized raoellid, would have been approximately the size of a coyote. Meanwhile, the smallest raoellid, Metkatius, was roughly the

Merycoidodon ("ruminating teeth") is an extinct genus of herbivorous artiodactyl of the family Merycoidodontidae, more popularly known by the name Oreodon ("hillock teeth"). It was endemic to North America during the Middle Eocene to Middle Miocene (46—16 mya) existing for approximately .

Poebrotherium ( ) is an extinct genus of camelid, endemic to North America. They lived from the Eocene to Miocene epochs, 46.3—13.6 mya, existing for approximately .

Anoplotherium is the type genus of the extinct Palaeogene artiodactyl family Anoplotheriidae, which was endemic to Western Europe. It lived from the Late Eocene to the earliest Oligocene. It was the fifth fossil mammal genus to be described with official taxonomic authority, with a history extending back to 1804 when its fossils from Montmartre in Paris, France were first described by the French naturalist Georges Cuvier. Discoveries of incomplete skeletons of A. commune in 1807 led Cuvier to thoroughly describe unusual features for which there are no modern analogues. His drawn skeletal

Elomeryx is an extinct genus of artiodactyl ungulate, and is among the earliest known anthracotheres. The genus was extremely widespread, first being found in Asia in the middle Eocene, in Europe during the latest Eocene, and having spread to North America by the early Oligocene. The closest living relatives of the Elomeryx are said suids, and hippopotamids (hippopotami and cetaceans). thumb|left|Restoration of E. armatus Elomeryx was about in body length, and had a long, vaguely horse-like head. It had small tusks which it used to uproot plants, and spoon-shaped incisors ideal for pulling an

Protylopus is an extinct genus of camel that lived during middle to late Eocene some 50-40 million years ago in North America.

Diacodexis is an extinct genus of small herbivorous mammals belonging to the family Diacodexeidae that lived in North America and Europe from 55.4 mya to 46.2 mya, existing for approximately .

Dichobunidae is an extinct family of basal artiodactyl mammals from the early Eocene to late Oligocene of North America, Europe, and Asia. The Dichobunidae include some of the earliest known artiodactyls, such as Diacodexis.

thumb|right|Skull of Anoplotherium|Anoplotherium commune, showing the unspecified dentition

Oromerycidae is a small (both in size and diversity), extinct family of artiodactyls (even-toed hoofed mammals) closely related to living camels, known from the early to late Eocene of western North America.

Hypertragulidae is an extinct family of Paleogene ruminants endemic to North America from the Eocene until the Oligocene.

Xiphodontidae (from Ancient Greek ξίφος (xíphos), meaning "sword", and ὀδούς (odoús), meaning "tooth") is an extinct family of herbivorous 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. Paraxiphodon suggests that they survived into the Lower Oligocene, at least.

Leptoreodon is an extinct genus of small Artiodactyla, of the family Protoceratidae, endemic to North America. It lived during the Late Eocene 40.4—37.2 Ma, existing for approximately . Leptoreodon resembled deer, but were more closely related to camelids.

Gagadon ("Gaga tooth") is an extinct genus of even-toed ungulate that lived in the early Eocene of North America. The type and only known species, Gagadon minimonstrum, was described in 2014 based on lower teeth and jaw fragments found in the Wasatch Formation of Bitter Creek, Wyoming. The genus is named in honor of the singer Lady Gaga, while the species name minimonstrum ("mini monster") refers simultaneously to the small size and presence of unusual cusps on the teeth and to Gaga's name for her fans, the "little monsters".

Leptotragulus is an extinct genus of protoceratid, endemic to North America. It lived during the Middle Eocene epoch (Uintan to Chadronian stage) 40.2—33.9 Ma, existing for approximately .

Leptomeryx is an extinct genus of artiodactyl that lived in North America during the middle Eocene through early Miocene. One of the earliest ruminants, it belongs to the extinct family Leptomerycidae, which is related to today's chevrotains. Most fossils were found in the badlands of the Midwestern United States in sedimentary rocks of the White River Group, in the Brule and Chadron formations. Additional remains have been reported from southern Canada and Mexico. The genus was scientifically described in 1853 by Joseph Leidy and includes several species.

Poebrodon is an extinct genus of terrestrial herbivore in the family Camelidae, endemic to North America during the Lutetian (early Middle) Eocene 46.2—42.0 mya, existing for approximately , Poebrodon is the oldest known camelid, living during the Uintan.

Agriochoerus is an extinct genus of scansorial herbivore of the tylopod family Agriochoeridae, endemic to North America. Agriochoerus and other agriochoerids possessed claws, which is rare within Artiodactyla, as well as likely being scansorial. Agriochoerus was first described in 1869.

Messelobunodon is an extinct genus of early even-toed ungulate.

Hypertragulus is an extinct genus of hypertragulid ruminant endemic to North America. It lived from the Late Eocene to the Middle Miocene, living , existing for approximately .

extinct family of mammals

Amphirhagatherium is an extinct genus of artiodactyl that lived in Northern Europe during the late Eocene to Early Oligocene.

Pseudoprotoceras is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to central North America. It lived during the Late Eocene 37.2—33.9 Ma, existing for approximately . Pseudoprotoceras resembled hornless deer, but were more closely related to camelids.

Toromeryx is a medium-sized extinct genus of Artiodactyla, of the family Protoceratidae, endemic to southwestern North America from the Eocene epoch (Late Uintan stage) 46.2—42 Ma, existing for approximately .

Bothriodon (Greek: "pit" (botros), "teeth" (odontes)) is an extinct genus of anthracotheriid artiodactyl from the late Eocene to early Oligocene of Asia, Europe, and North America.

Catodontherium is an extinct genus of Palaeogene artiodactyl belonging to the family Anoplotheriidae. It was endemic to Western Europe and had a temporal range exclusive to the middle Eocene, although its earliest appearance depends on whether C. argentonicum is truly a species of Catodontherium. It was first named Catodus by the French palaeontologist Charles Depéret in 1906, who created two species for the genus and later changed the genus name to Catodontherium in 1908. The Swiss palaeontologist Hans Georg Stehlin renamed one species and classified two other newly erected species to Catodon

Archaeomeryx is an extinct genus of ruminant that lived early in the Eocene. It is believed to be close to the ancestry of the group Pecora, which includes deer, giraffes, cows and their relatives. Unlike the modern members of this group, it had a set of functioning incisors in the upper jaw. It was small in size, comparable to a modern-day mouse deer. It was also very rabbit-like and had several distinctive characteristics. It lived in present-day China 35 to 40 million years ago.

Paratylopus is an extinct genus of camelid, endemic to North America. It lived from the Oligocene to the Middle Miocene 33.9—16.0 Mya, existing for approximately . Fossils have been found in western Wyoming, and from eastern Nebraska to northeastern Colorado and southwestern South Dakota.

Poabromylus is an extinct genus of small artiodactyl, of the family Protoceratidae, endemic to North America. They lived during the Late Eocene 40.4–33.9 Ma, existing for approximately . They resembled deer but were more closely related to camelids.

Trigenicus is an extinct genus of small artiodactyl in the family Protoceratidae, endemic to North America. It lived from the Late Eocene 37.2—33.9 Ma, existing for approximately . Trigenicus resembled deer, but were more closely related to camelids.

Xiphodon (from Ancient Greek ξίφος (xíphos), meaning "sword", and ὀδούς (odoús), meaning "tooth") is the type genus of the extinct Palaeogene artiodactyl family Xiphodontidae. It, like other xiphodonts, was endemic to Western Europe and lived from the Middle Eocene up to the earliest Oligocene. Fossils from Montmartre in Paris, France that belonged to X. gracilis were first described by the French naturalist Georges Cuvier in 1804. Although he assigned the species to Anoplotherium, he recognized that it differed from A. commune by its dentition and limb bones, later moving it to its own subgen