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Protorohippus montanum

Mammalia - Perissodactyla - Equidae

Taxonomy
Hyracotherium montanum was named by Wortman (1896). Its type specimen is AMNH 4593, a mandible (right and left mandible frag- ments with left P4, M2–M3, and right P4), and it is a 3D body fossil.

It was recombined as Pliolophus montanus by Hay (1902); it was recombined as Eohippus montanus by Granger (1908) and Stirton (1940); it was recombined as Protorohippus montanus by Froehlich (1999); it was recombined as Protorohippus montanum by Froehlich (2002).

Synonymy list
YearName and author
1896Hyracotherium montanum Wortman
1902Pliolophus montanus Hay
1908Eohippus montanus Granger
1940Eohippus montanus Stirton
1999Hyracotherium montanum Froehlich
1999Protorohippus montanus Froehlich
2002Protorohippus montanum Froehlich p. 179

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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
Synapsida()
Therapsida()
RankNameAuthor
infraorderCynodontia()
Epicynodontia
infraorderEucynodontia
Probainognathia
Mammaliamorpha
Mammaliaformes
classMammalia
subclassTribosphenida()
infraclassEutheria()
Placentalia
orderPerissodactyla()
suborderLophodontomorpha
infraorderEuperissodactyla
Hippomorpha
superfamilyEquoidea
familyEquidae
genusProtorohippus
speciesmontanum()

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
D. J. Froehlich 2002This taxon has no unambiguous autapomorphies but can be diagnosed by the characters of the node containing it and all more-derived equids: upper molar metaconule weak and stepped (Character 49, 0 to 1), upper molar convergence <90° (Character 65, 1 to 2), lower molar paracristid angle a30° (Character 87, 1 to 2), lower molar paracristid angle sharp (Character 88, 0 to 1), lower molar protolophid backwall steep (Character 90, 1 to 0), and lower preultimate molar hypoconulid closely appressed against hypolophid (Character 95, 0 to 1), but lacks the fol- lowing characters: P4 paraconule significantly anterior of line between paracone and protocone (Character 32, 0 to 1), upper molar mesostyle small (Character 46, 0 to 1), upper molar ectoloph moderately lophoid (Character 52, 0 to 1), upper molar protoloph sub-lophoid (Character 53, 0 to 1), P3 hypoconid large (Character 72, 0 to 1), lower molar cristid obliqua slightly lingual (Character 80, 2 to 1), lower molar protolophid incipiently lophoid (Character 89, 1 to 2), lower molar hypolophid straight (Character 92, 1 to 0), M3 hypolophid strong (Character 104, 1 to 2), and astragalar trochlea inclined >10° (Character 121, 1 to 2).