|Basic info||Taxonomic history||Classification||Relationships|
|Morphology||Ecology and taphonomy||External Literature Search||Age range and collections|
Mammalia - Ungulata - Merycoidodontidae
It was assigned to Oreodontoidea by Scott (1940); to Merycoidodontoidea by Thorpe (1937), Ferrusquia-Villafranca (1969) and Lander (1998); and to Artiodactyla by Cook (1912), Stevens et al. (1969), Stevens and Stevens (1996) and Parris and Grandstaff (2003).
|Year||Name and author|
|1884||Oreodontidae Cope p. 503|
|1889||Oreodontidae Cope p. 876|
|1891||Oreodontidae Cope p. 21|
|1910||Oreodontidae Gregory p. 466|
|1912||Merycoidodontidae Cook p. 45|
|1937||Merycoidodontidae Thorpe p. 31|
|1940||Merycoidodontidae Scott p. 648|
|1950||Phenacocoelinae Schultz and Falkenbach p. 95|
|1954||Desmatochoerinae Schultz and Falkenbach p. 153|
|1969||Merycoidodontidae Stevens et al. p. 26|
|1969||Phenacocoelinae Stevens et al. p. 26|
|1996||Merycoidodontidae Stevens and Stevens p. 510|
|1996||Phenacocoelinae Stevens and Stevens p. 510|
|1997||Oreodontidae McKenna and Bell p. 408|
|2003||Merycoidodontidae Parris and Grandstaff p. 63|
|2009||Oreodontidae Morgan et al.|
|2011||Oreodontidae Lander and Lindsay p. 221|
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If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.
|M. S. Stevens and J. B. Stevens 1996||Oreodonts are suiform, selenodont artiodactyls that differ from most Agriocho- eridae by lack of a divided P4para-metacone, usual absence of molar labial ribs, the posterior arm of the protoselene usually directed medially and deeply into the median valley between the protocone and hypocone, usual absence of protoconules, and a usually closed postorbital. The Merycoidodontidae usually lack diastema (except those to receive the caniform teeth), have a full dental series of 13/3, Cl/1, P4/4, and M3/3, an incisiform lower canine, caniform Pt, and molars with W-shaped ectolophs.
Oreodont crania primitively have rather steep premaxillae, usually short Subnasal L. and a strongly convex nasal profile, but the profile becomes progres- sively straighter or more concave, and the Subnasal L. increases in some genera as the nasal notch migrates posteriorly. One genus firmly coalesces the rostrum ventral to the nasal aperture which causes the external nares to migrate posteriorly , and three genera greatly shorten the length of the nasal bones. Oreodont skulls are usually mesocephalic but certain groups become more brachycephalic, and one group becomes quite dolichocephalic. The orbits are situated in the mid- cranial region, and are primitively located relatively low on the sides of the face. Facial vacuities are absent in primitive species but are characteristic of numerous derived genera. The zygoma are usually unspecialized but become massively upturned in several taxa. The nuchal crest is primitively narrow and protracted strongly posteriorly, but the crest becomes less protracted and considerably expanded laterally in some specialized forms and a sagittal table may develop. Some genera progressively either develop or reduce the depth of the preorbital fossae, and auditory bullae vary from small to notably enlarged. Oreodont lower jaws consistently have a greatly enlarged, rounded angular region that is not much expanded below the ventral border of the horizontal ramus.