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Ustatochoerus medius

Mammalia - Artiodactyla - Merycoidodontidae

Taxonomy
Merychyus medius was named by Leidy (1858). Its type specimen is NM 118, a mandible (Partial left ramus with m1-m3), and it is a 3D body fossil. Its type locality is Niobrara River (coll. Hayden 1857), which is in a Miocene terrestrial horizon in the Loop Fork Formation of Nebraska.

It was recombined as Metoreodon medius by Thorpe (1937); it was recombined as Ustatochoerus medius by Schultz and Falkenbach (1941), Schultz and Falkenbach (1947), Galbreath (1953), Cassiliano (1980), Stevens and Stevens (1989), Voorhies (1990) and Stevens and Stevens (2007).

Synonyms
Synonymy list
YearName and author
1858Merychyus medius Leidy p. 26
1884Merychyus medius Cope p. 545
1890Merycochoerus coenopus Scott
1890Merycochoerus cenopus Scott and Osborn p. 73
1937Metoreodon medius Thorpe
1941Ustatochoerus medius Schultz and Falkenbach p. 23
1947Ustatochoerus medius Schultz and Falkenbach
1953Ustatochoerus medius Galbreath
1980Ustatochoerus medius Cassiliano
1988Merychyus medius Kelly and Lander
1989Merychyus medius Lander and Kelly
1989Ustatochoerus medius Stevens and Stevens
1990Ustatochoerus medius Voorhies
1998Merychyus medius Lander
2007Ustatochoerus medius Stevens and Stevens p. 166
2009Merychyus medius Morgan et al. p. 95

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RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
phylumChordataHaeckel 1847
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
Sarcopterygii
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda()
Reptiliomorpha
Anthracosauria
Batrachosauria()
Cotylosauria()
Amniota
RankNameAuthor
Synapsida()
Therapsida()
infraorderCynodontia()
Epicynodontia
infraorderEucynodontia
Probainognathia
Mammaliamorpha
Mammaliaformes
classMammalia
orderArtiodactyla()
suborderTylopoda()
superfamilyOreodontoidea
familyMerycoidodontidaeThorpe 1923
subfamilyUstatochoerinae
genusUstatochoerus
speciesmedius()

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.

Diagnosis
ReferenceDiagnosis
C. B. Schultz and C. H. Falkenbach 1941
SKULL.-Smaller than that of U. profectus but larger than that of U.? schrammi; nasals longest of genus (in proportion to size of skull); anterior tip of nasals retracted to region above PLP 2•
MANDIBLE.-Typical of genus; similar to that of U. profectus except for smaller size.
DENTITION.-Cusps on superior and inferior premolars not as well developed as in U. major or U. profectus.
LIMBs.-Smaller than those of U. profectus.