oreodont

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Oreodonts Fossil range: Eocene to Late Pliocene
Conservation status
Extinct (fossil)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Suborder: Oreodonta Family: Merycoidodontidae
Subfamilies
Oreonetinae Leptaucheniinae Oreodontinae (Merycoidodontinae) Miniochoerinae Desmatochoerinae Promerycochoerinae Merychyinae Eporeodontinae Phenacocoelinae Ticholeptinae

Sometimes called a prehistoric "ruminating hog," (although they are neither Ruminants nor hogs), the typical oreodont ("Mountain teeth") was a sheep-sized (though some genera grew to the size of cattle), cud-chewing plant-eater with a short face, tusk-like canine teeth, heavy body, long tail, short feet, and four-toed hooves.

Taxonomy

The now-extinct suborder Oreodonta was distantly related to pigs, hogs, camels, hippopotamuses, and the pig-like peccaries. Indeed, some scholars place the oreodont family Oreodontidae (also known as Merycoidodontidae) within the pig-related suborder Suina (a.k.a. Suiformes). Still other experts put the oreodonts together with the short-lived cainotheres in the taxonomic suborder Ancodonta comprising these two groups of extinct ancodonts.

Scholars agree, however, that the oreodont was an early form of even-toed ungulate, belonging to the order Artiodactyla among the placental mammals. Over 50 species of Oreodonta have been described in the paleozoological literature. Of these, by far the most well-known oreodont genus is Merycoidodon, formerly and popularly known as Oreodon.

Natural history

This diverse group of stocky prehistoric mammals grazed amid the grasslands, prairies or savannas of North and Central America throughout much of the Cenozoic era. First appearing 48 million years ago (m.y.a.) during the warm Eocene epoch of the Paleogene period, the oreodonts dominated the American landscape 34 to 23 m.y.a. during the dry Oligocene epoch of the late Paleogene. But they mysteriously disappeared 4 m.y.a. during the colder Pliocene epoch of the late Neogene period. Today, fossil jaws and teeth of the Oreodonta are commonly found amid the Oreodon beds of the White River badlands in South Dakota, Nebraska, and Wyoming. Many oreodont bones have also been reported at the John Day Fossil Beds National Monument in Oregon.

Classification

The family Merycoidodontidae is divided up into ten subfamilies. Four genera, Metoreodon, Promerycochoerus, Pseudoleptauchenia, and Superdesmatochoerus, are not included in any of the following ten subfamilies because they are either regarded as basal oreodonts, or their status within the family remains uncertain.

• Subfamily Oreonetinae, which contains Bathygenys alpha, Megabathygenys, Oreonetes, and Parabathygenys
• Subfamily Leptaucheniinae, which is divided into two tribes, Leptaucheniini, containing Limnenetes, Pseudocyclopidius, Hadroleptauchenia, Leptauchenia, Pithecistes, and Cyclopidius, and the tribe Sespiini, which contains Sespia (and Megasespia before it was fused with Sepsia).
• Subfamily Oreodontinae (also referred to as "Merycoidodontinae"), which contains Aclistomycter middletoni, Merycoidodon ("Oreodon"), Otionohyus, Paramerycoidodon, Genetochoerus, Pseudogenetochoerus, and Epigenetochoerus.
• Subfamily Miniochoerinae, which contains Stenopsochoerus ("Pseudostenopsochoerus"), Platyochoerus, Parastenopsochoerus, and Miniochoerus {"Paraminiochoerus").
• Subfamily Desmatochoerinae, which contains Prodesmatochoerus, Subdesmatochoerus, Desmatochoerus, Subdesmatochoerus, Megoreodon and Pseudodesmatochoerus.
• Subfamily Promerycochoerinae, which contains Promesodreodon, Promerycochoerus, Merycoides and Mesoreodon.
• Subfamily Merychyinae, which contains Oreodontoides, Paroreodon, Paramerychyus and Merychyus.
• Subfamily Eporeodontinae, which contains Dayohyus and Eporeodon.
• Subfamily Phenacocoelinae, which contains Phenacocoelus Submerycochoerus, Pseudomesoreodon and Hypsiops.
• Subfamily Ticholeptinae, which contains Mediochoerus, Ticholeptus ("Poatrephes"} and Ustatochoerus.
• Subfamily Merycochoerinae, which contains Merycochoerus and Brachycrus.

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