Eocene mammals

Basilosaurus (meaning "king lizard") is a genus of large, predatory, prehistoric archaeocete whale from the late Eocene, approximately 41.3 to 33.9 million years ago (mya). First described in 1834, it was the first archaeocete and prehistoric whale known to science. Fossils attributed to the type species B. cetoides were discovered in the southeastern United States. The generic name, meaning "king lizard", was given due to the initial misconception about the fossil material as that of a giant reptile. The animal was later found to be an early marine mammal, prompting attempts at renaming the c

Brontotheriidae (or Titanotheriidae), is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs from the Eocene epoch. Brontotheres had a Holarctic distribution, with the exception of Western Europe: their fossils have been found in North America and Asia, with a few also known from Eastern Europe. In larger and often better-known genera of the group, a paired or battering-ram-like horn was present on the snout above the eye socket, made of bone, unlike the horns of rhinoceroses. However, this feature is not present in all me

Hyaenodon ("hyena-tooth") is an extinct genus of carnivorous placental mammals from the tribe Hyaenodontini, part of the subfamily Hyaenodontinae (which is within the family Hyaenodontidae), that belonged to the now extinct order Hyaenodonta. The genus was found lived in Eurasia and North America from the Middle Eocene to the Early Miocene, from 38 to 17 million years ago, existing for . Hyaenodon first evolved in Asia, probably evolving from Propterodon.

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

Embrithopoda ("heavy-footed" in Ancient Greek) is an order of extinct paenungulate mammals known from Asia, Africa and Eastern Europe. Most of the embrithopod genera are known exclusively from jaws and teeth dated from the late Paleocene to the late Eocene; however, the order is best known from its terminal member, the large Arsinoitherium.

Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms resembling animals as disparate as rabbits and rhinoceroses. Notoungulata are the largest group of South American native ungulates, with over 150 genera in 14 families having been described, divided into two major subgroupings, Typotheria and Toxodontia. Notoungulates first diversified during the Eocene. Their diversity declined from the late Neogene onw

Plesiadapis (near Adapis) is an extinct genus of mammal closely related to primates, found in North America and western Europe. The type species, P. tricuspidens, was described in 1877 by François Louis Paul Gervaise, based on a partial left mandible (lower jaw) uncovered in France. Fourteen valid species have since been named.

Dinocerata, from Ancient Greek (), "terrible", and (), "horn", or Uintatheria, is an extinct order of large herbivorous hoofed mammals with horns and protuberant canine teeth, known from the Paleocene and Eocene of Asia and North America. With body masses ranging up to they represent some of the earliest known large mammals.

Hyaenodontidae ("hyena teeth") is a family of placental mammals in the extinct superfamily Hyaenodontoidea. Hyaenodontids arose during the early Eocene and persisted well into the early Miocene. Fossils of this group have been found in Asia, North America and Europe.

Phenacodus (Greek: "deception" (phenax), "tooth' (odus)) is an extinct genus of mammals from the late Paleocene through middle Eocene, about 55 million years ago. It is one of the earliest and most primitive of the ungulates, typifying the family Phenacodontidae and the order Perissodactyla.

Taeniodonta ("banded teeth") is an extinct order of eutherian mammals, that lived in North America and Europe from the late Cretaceous (Maastrichtian) to the middle Eocene. They were among the first mammals to evolve large body sizes (comparable to a modern wild boar or American black bear), as well as ever-growing teeth for eating tough plants.

Coryphodon (from Greek , "point", and , "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of pantodonts of the family Coryphodontidae.

Eomanis ("dawn pangolin") is the earliest known true (and scaled) pangolin from extinct family Eomanidae (and extinct superfamily Eomanoidea) within suborder Eupholidota. It lived during the Eocene in Europe. Eomanis fossils found in the Messel Pit in Germany are very similar in size and anatomy to living pangolins of the genus Manis, indicating that pangolins have remained largely unchanged in morphology and behavior for 50 million years. However, unlike modern pangolins, its tail and legs did not bear scales. According to the stomach contents of the excellently preserved Messel specimens, Eo

Arctocyonidae (from Ancient Greek ἄρκτος (árktos), meaning "bear", and κύων (kúon), meaning "dog", and thus, "bear-dog") is an extinct, possibly polyphyletic family of placental mammals which lived from the late Cretaceous to the early Eocene. They were initially regarded as creodonts, though have since been reassigned to an order of their own, the Arctocyonia. Some have suggested that arctocyonids are ancestral to modern-day artiodactyls, or that they form a sister group. However, more recent phylogenetic analyses suggest that arctocyonids may represent an artificial grouping of extinct ungul

Leptictida (leptos iktis "small/slender weasel") is a possibly paraphyletic extinct order of eutherian mammals. Their classification is contentious: according to cladistic studies, they may be (distantly) related to Euarchontoglires (rodents, primates and their relatives), although they are more recently regarded as the first branch to split from basal eutherians. One recent large-scale cladistic analysis of eutherian mammals favored lepictidans as close to the placental crown-clade; and several other recent analyses that included data from Cretaceous non-eutherian mammals found Leptictis to b

Kopidodon is an extinct genus of placental mammals from subfamily Paroxyclaeninae within family Paroxyclaenidae, that lived during the middle Eocene in Germany.

Phenacodontidae is an extinct family of large herbivorous mammals traditionally placed in the "wastebasket taxon" Condylarthra, which may instead represent early-stage perissodactyls. They lived from the late early Paleocene to early middle Eocene (about 60–50 million years ago) and their fossil remains have been found in North America and Europe. The only unequivocal Asian phenacodontid is Lophocion asiaticus.

Plesiadapidae is a family of plesiadapiform mammals related to primates known from the Paleocene and Eocene of North America, Europe, and Asia. Plesiadapids were abundant in the late Paleocene, and their fossils are often used to establish the ages of fossil faunas.

Pachyaena (literally, "thick hyena") was a genus of heavily built, relatively short-legged mesonychids. Mesonychids were part of the now extinct order known as Mesonychia, a group mammalian predators that evolved before modern ungulates or carnivorans. Despite this, mesonychians are found to have combined characteristics of both carnivorans and ungulates. The genus likely originated from Asia and dispersed to Europe, and from there to North America across a land bridge in what is now the North Atlantic ocean. Pachyaena would later be replaced by Dissacus in Europe.

Hyainailouridae ("hyena-like cats") is a paraphyletic family of extinct predatory mammals within the polyphyletic superfamily Hyainailouroidea within extinct order Hyaenodonta. Fossil records show hyainailourids arose during the Middle Eocene, although Early Eocene origin is suspected, the family persisted into the Late Miocene.'' Fossils of this group have been found in Eurasia, Africa, and North America. ==Classification and phylogeny== ===Relations=== Hyainailouridae used to be considered a subfamily of Hyaenodontidae, but cladistic study by Sole et al.'', (2013, 2015) treats it as a disti

Heterohyus is an extinct genus of apatemyid from the early to late Eocene. A small, tree-dwelling creature with elongated fore- and middle fingers, in these regards it somewhat resembled a modern-day aye-aye.

Lesmesodon ("tooth from Messel") is an extinct genus of placental mammals from extinct clade Proviverrinae within extinct superfamily Hyaenodontoidea (in extinct order Hyaenodonta), that lived during the Early to Middle Eocene. It was found in France and in the Messel Pit in Germany.

Palaeoryctidae ("ancient diggers") is an extinct family of non-specialized eutherian mammals from extinct order Palaeoryctida, that lived in North America, Europe, Asia and Africa from the late Cretaceous to the middle Eocene.

Hapalodectes (literal translation 'soft biter'; from ('soft, tender') and ('biter')) is an extinct genus of otter-like mesonychians from the Late Paleocene to Early Eocene, some 55million years ago. Although the first fossils were found in the Eocene strata of Wyoming, the genus originated in Mongolia, as the oldest species is H. dux, which was found in Late Paleocene strata in the Naran Bulak Formation. left|thumb|Life restoration of H. serus The genus was once suggested to be related to the Archaeoceti, such as Pakicetus, due to numerous similarities between the skull and tooth anatomies of

Patriomanis ("father of pangolins") is an extinct genus of pangolin from extinct family Patriomanidae. It lived from the late Eocene to early Oligocene of North America and it currently represents the only pangolin known from the Western Hemisphere. The genus contains one species, P. americana, which is only known from six specimens, mostly from the Chadronian White River Formation of Wyoming. It had long digits and a prehensile tail, suggesting that it was arboreal, and its jaw was capable of opening wider than modern pangolins. Its ears and the hair between its scales were also longer than m

Pantolestidae ("all robbers") is a paraphyletic family of placental mammals from extinct order Pantolesta, that lived in North America, Asia and Europe from the early Paleocene to middle Oligocene. They first appear in North America, whence they spread to Europe and Asia.

Palaeosinopa ("ancient Sinopa") is an extinct genus of semi-aquatic mammals belonging to the subfamily Pantolestinae within family Pantolestidae. Species in this genus lived from the late Paleocene to early Eocene in North America and Europe. Their diet consisted of other aquatic life forms.

Euromanis ("european pangolin") is one of the earliest known pangolin genera. It lived during the middle Eocene in Europe. Euromanis fossils found in the Messel Pit in Germany. Unlike modern pangolins, it did not bear scales on its body.

Limnocyon ("swamp dog") is an extinct paraphyletic genus of limnocyonin hyaenodonts that lived in North America during the middle Eocene. Fossils of this animal have been found in California, Utah and Wyoming.

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 in Paleocene to Early Eocene aged strata in France, Asia and southwest North America, from 66 to 50.3 mya, existed for approximately .

The Amphilemuridae are a family of extinct mammals belonging to the order Eulipotyphla, from the Eocene of Europe and North America. ==Description== Amphilemurids were generally small in size and may have resembled moonrats in life. Some species had spines like those of hedgehogs, while others were almost free of spines or had bristly coats. Most species are known only from teeth.

Epoicotheriidae ("strange beasts") is an extinct paraphyletic family of insectivorous placental mammals within extinct order Palaeanodonta, that lived in North America, Asia and Europe from the middle Paleocene to early Oligocene. Epoicotheriids were fossorial mammals. Late Eocene/early Oligocene genera were highly specialized animals that were convergent with the talpids, golden moles and marsupial mole in the structure of their skulls and forelimbs, and would have had a similar lifestyle as subterranean burrowers. They are considered among the most specialized animals that have ever evolved

Archaeopithecidae is an extinct family comprising two genera of notoungulate mammals, Teratopithecus and Archaeopithecus, both known from the Eocene of Argentina.

thumb|left|Life restoration Hypercoryphodon is an extinct genus of rhinoceros-sized pantodont native to Late Eocene Mongolia, and was very similar to its ancestor, Coryphodon. Described from a skull, Hypercoryphodon is a quadrupedal hippopotamus-like herbivore that may have been able to adapt its feeding to suit different situations. It is thought to have possibly lived in wetland to forest ecosystems that it might have shared with other herbivores such as dinoceratans like Gobiatherium. The low-crowned teeth of Hypercoryphodon were adapted for feeding on soft aquatic vegetation.

Stylinodontidae ("teeth with pilar-like fibers") is an extinct family of mammals from extinct superfamily Stylinodontoidea within extinct order Taeniodonta, that lived in North America from the early Paleocene to middle Eocene.

Prolimnocyon ("before Limnocyon") is an extinct paraphyletic genus of limnocyonin hyaenodonts that lived in Asia and North America during the Late Paleocene to Middle Eocene. Prolimnocyon chowi is one of the earliest known member of the order Hyaenodonta and clade Limnocyoninae.

Ptilodontoidea is a group of extinct mammals from the Northern Hemisphere. They were generally small, somewhat rodent-like creatures of the extinct order Multituberculata.

Archaeohyracidae is an extinct family of notoungulate mammals known from the Paleocene through the Oligocene of South America. First named in 1897, it is now thought to be paraphyletic, rather than a genuine group of closely related animals with a single, unique, ancestor.

Adapisoriculidae is an extinct family of non-placental eutherian mammals which was present during the Paleogene and possibly the Late Cretaceous. They were once thought to be members of the order Erinaceomorpha, closely related to the hedgehog family (Erinaceidae), because of their similar dentition, or to be basal Euarchontans. They were also thought to be marsupials at one point. Most recent studies show them to be non-placental eutherians, however.

Cryptomanis ("hidden pangolin") is an extinct genus of pangolin from extinct family Patriomanidae. The genus is only known from the holotype specimen from middle Eocene deposits from Inner Mongolia, China. The holotype, AMNH 26140, was labeled as an unnamed pangolin in the fossil collection for decades. The remains consist of an incomplete postcranial specimen, with nearly complete hind limbs, an incomplete pelvis, a complete lumbar series from an incomplete vertebral column, numerous fragmentary remains of rib and sternal bones, a fragmentary scapula, and partially preserved forelimbs. Based

Galecyon ("polecat-like dog") is an extinct genus of placental mammals from extinct order Hyaenodonta, that lived in Europe and North America (found in the Clarks Fork and Powder River basins of Wyoming) during the early Eocene.

Cynohyaenodon ("dog-like Hyaenodon") is an extinct paraphyletic genus of placental mammals from extinct family Hyaenodontidae that lived from the early to middle Eocene in Europe.

Eurymylidae is a family of extinct simplicidentates. Most authorities consider them to be basal to all modern rodents and suggest they may have been the ancestral stock from which the most recent common ancestor of all modern rodents (crown rodents) arose. However, the better-known eurymylids, including Eurymylus, Heomys, Matutinia, and Rhombomylus, appear to represent a monophyletic side branch that is that is that is not directly ancestral to rodents (Meng et al., 2003). Huang et al. (2004) have argued that Hanomys, Matutinia, and Rhombomylus form a clade characterized by distinctive feature

Gomphos is an extinct genus of early lagomorphs from the early Eocene of the China and Mongolia.

Homalodotheriidae is an extinct family comprising four genera of notoungulate mammals known from the Late Eocene (Tinguirirican) through Late Miocene (Chasicoan) of Argentina and Chile in South America.

Pyrocyon ("fire dog") 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.

Eurotherium ("european beast") is an extinct paraphyletic genus of placental mammals from the extinct family Hyaenodontidae that lived from the Early to Middle Eocene in Europe.

Paroxyclaenidae is an extinct family of pantolestan mammals that ranges from the early Eocene to the early Oligocene. Most members of the family are found throughout Europe though the youngest and largest member, Welcommoides, lived in what is now Pakistan. Similar to a large amount of other more basal Cenozoic mammals, their taxonomic placement is not well understood with suggestions ranging from being within Carnivora to within the former order Creodonta. Today, them and Pantolesta as a whole are considered Eutherian mammals that may be a part of another problematic order, Cimolesta.

Plesiadapoidea was an extinct superfamily of primates that existed during the Paleocene and Eocene in North America, Europe, and Asia.

Palaeoamasiidae or Palaeoamasinae is an extinct taxon of embrithopod mammals that have been found in Romania and Anatolia where they lived on the shores of the Tethys Ocean.

Gustafsonia is an extinct genus of carnivoran belonging to the family Amphicyonidae (a bear dog). The type species, Gustafsonia cognita, was described in 1986 by Eric Paul Gustafson, who originally interpreted it as a miacid and named it Miacis cognitus. It was subsequently considered to be the only species of the diverse genus Miacis that belonged to the crown-group Carnivora, within the Caniformia, and it was ultimately assigned to the family Amphicyonidae. The type specimen or holotype was discovered in Reeve's bonebed, western Texas, in the Chambers Tuff Formation in 1986. The University o

Conoryctidae ("cone diggers") is an extinct family of mammals from extinct order Taeniodonta, that lived in North America and Europe from the early Paleocene to early Eocene.

Mimoperadectes is an extinct genus of metatherian mammal from the Eocene of North America. thumb|left|Restoration

Stylolophus is a genus of basal embrithopod from Eocene Africa. There is one described species, S. minor, and one indeterminate specimen.

Dawsonicyon ("Dawson's dog") is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to middle Eocene. Fossils of type species Dawsonicyon isami are known from the ‘Bridger B’, site of Black's Fork member of the Bridger Formation in Wyoming, and includes an almost complete skeleton (holotype DMNH 19585).

Plagiomene is an extinct genus of early flying lemur-like mammal from North America that lived during the Eoecene epoch.

Indohyaenodon ("indian Hyaenodon") is an extinct genus of placental mammals from family Indohyaenodontidae within extinct order Hyaenodonta, that lived during the early Eocene in India.