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Orohippus sylvaticus

Mammalia - Perissodactyla - Equidae

Taxonomy
Lophiotherium sylvaticum was named by Leidy (1870). Its type specimen is USNM 3753, a mandible (fragment of left ramus with p4-m3 ), and it is a 3D body fossil.

It was recombined as Orotherium sylvaticus by Marsh (1872); it was recombined as Orotherium sylvaticum by Cope (1873); it was recombined as Pliolophus sylvaticus by Cope (1884); it was recombined as Pachynolophus sylvaticus by Roger (1896); it was recombined as Orohippus sylvaticus by Trouessart (1898), Matthew (1899), Hay (1902), Granger (1908), Hay (1930), Stirton (1940), Kitts (1957), Gazin (1976) and MacFadden (1998).

Synonyms
  • Orotherium uintanum was named by Marsh (1872) [genotype].

    It was recombined as Pliolophus uintanus by Cope (1884); it was recombined as Pachynolophus uintanus by Roger (1896); it was recombined as Epihippus uintanus by Trouessart (1898); it was recombined as Orohippus uintanus by Matthew (1899), Hay (1902), Granger (1908), Hay (1930) and Stirton (1940); it was synonymized subjectively with Orohippus sylvaticus by Kitts (1957).
Synonymy list
YearName and author
1870Lophiotherium sylvaticum Leidy p. 126
1872Orotherium sylvaticus Marsh
1872Orotherium uintanum Marsh p. 217
1873Orotherium sylvaticum Cope p. 1
1875Orotherium vintanum Cope p. 18
1884Pliolophus sylvaticus Cope
1884Pliolophus uintanus Cope
1896Pachynolophus sylvaticus Roger
1896Pachynolophus uintanus Roger
1898Epihippus uintanus Trouessart
1898Orohippus sylvaticus Trouessart
1899Orohippus sylvaticus Matthew
1899Orohippus uintanus Matthew
1902Orohippus sylvaticus Hay
1902Orohippus uintanus Hay
1908Orohippus sylvaticus Granger
1908Orohippus uintanus Granger
1930Orohippus sylvaticus Hay
1930Orohippus uintanus Hay
1940Orohippus sylvaticus Stirton
1940Orohippus uintanus Stirton
1957Orohippus sylvaticus Kitts p. 21
1976Orohippus sylvaticus Gazin p. 21
1998Orohippus sylvaticus MacFadden p. 543

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RankNameAuthor
kingdomAnimalia()
Triploblastica
Nephrozoa
Deuterostomia
phylumChordataHaeckel 1847
OlfactoresJefferies 1991
subphylumVertebrata
Gnathostomata()
Osteichthyes()
Sarcopterygii
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda()
Reptiliomorpha
Anthracosauria
Batrachosauria()
Cotylosauria()
Amniota
Synapsida()
RankNameAuthor
Therapsida()
infraorderCynodontia()
Epicynodontia
infraorderEucynodontia
Probainognathia
Mammaliamorpha
Mammaliaformes
classMammalia
subclassTribosphenida()
infraclassEutheria()
Placentalia
orderPerissodactyla()
suborderLophodontomorpha
infraorderEuperissodactyla
Hippomorpha
superfamilyEquoidea
familyEquidae
genusOrohippus
speciessylvaticus()

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. B. Kitts 1957No diastema between P1 and P2. P2 triangular. Anteroexternal angle of P3 more acute than in O. pumilus. Protocone of P3 slightly external of hypocone. P4 molariform but slightly narrower internally than externally. Ectoloph on molars rises nearly to crest of external cusps. Parastyle and mesostyle strong. No diastema between p1 and p2. Protoconid and metaconid closer together than hypoconid and entoconid in p4 and lower molars. p4 and m1 and often m2 and m3 distinctly narrower anteriorly than posteriorly. Heel of m3 relatively long and narrow and unconstricted anteriorly.
C. L. Gazin 1976No diastema between Pl and p2. p2 triangular. Antero- external angle of P3 more acute than in 0. pumilus. Protocone of P3 slightly external of hypocone. P4 molariform but slightly narrower in- ternally than externally. Ectoloph on molars rises nearly to crest of external cusps. Parastyle and mesostyle strong. No diastema between P1 and P2. Protoconid and metaconid closer together than hypoconid and entoconid in P4 and lower molars. P4 and M1 and often M2 and M3 distinctly narrower anteriorly than posteriorly. Heel of M3 relatively long and narrow and unconstricted anteriorly.