PBDB Taxon

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Orohippus pumilus

Mammalia - Perissodactyla - Equidae

Taxonomy

Lophiodon pumilus was named by Marsh (1871) [genotype; not the same as "Lophiodon pumilus"; also said to be 1871, confusing this with Lophiodon pumilus]. It is a 3D body fossil. Its type locality is Grizzly Buttes, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming. It is the type species of Helohippus.

It was recombined as Hyrachyus pumilus by Leidy (1872); it was synonymized subjectively with Orohippus procyoninus by Cope (1873) and Cope (1875); it was recombined as Helohippus pumilus by Marsh (1892), Matthew (1899) and Hay (1902); it was recombined as Pachynolophus pumilus by Roger (1896); it was recombined as Helaletes pumilus by Wood (1934); it was recombined as Orohippus pumilus by Scott et al. (1871), Marsh (1872), Marsh (1874), Matthew (1899), Carrano (1902), Granger (1908), Stirton (1940), Kitts (1957), Gazin (1976), MacFadden (1998) and Froehlich (2002).

Synonyms

Helotherium procyoninum was named by Cope (1871) [genotype].

It was recombined as Orohippus procyoninus by Cope (1875), Hay (1902) and Matthew (1909); it was recombined as Hyracotherium procyoninum by Cope (1877) and Matthew (1899); it was recombined as Lambdotherium procyoninum by Cope (1884) and Roger (1896); it was synonymized subjectively with Orohippus pumilus by Marsh (1874), Trouessart (1905), Granger (1908), Osborn (1929) and Kitts (1957).
Hyracotherium osbornianum was named by Cope (1883). It is a 3D body fossil. Its type locality is Black's Fork, which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was recombined as Orohippus osbornianus by Trouessart (1898), Hay (1902), Hay (1930) and Stirton (1940); it was synonymized subjectively with Orohippus pumilus by Kitts (1957).
Lophiotherium ballardi was named by Marsh (1871) [genotype].

It was recombined as Orotherium ballardi by Marsh (1872); it was recombined as Pachynolophus ballardi by Roger (1896); it was synonymized subjectively with Orohippus sylvaticus by Matthew (1899); it was recombined as Orohippus ballardi by Hay (1902), Granger (1908), Hay (1930) and Stirton (1940); it was synonymized subjectively with Orohippus pumilus by Kitts (1957).
Oligotomus cinctus was named by Cope (1873) [genotype].

It was recombined as Pliolophus cinctus by Cope (1884); it was recombined as Pachynolophus cinctus by Roger (1896); it was recombined as Orohippus cinctus by Wortman (1896), Matthew (1899), Hay (1902) and Hay (1930); it was synonymized subjectively with Orohippus ballardi by Granger (1908); it was synonymized subjectively with Orohippus pumilus by Kitts (1957).
Orohippus atavus was named by Granger (1908). Its type locality is Cottonwood Creek (Lower Bridger), which is in a Bridgerian terrestrial horizon in the Bridger Formation of Wyoming.

It was synonymized subjectively with Orohippus pumilus by Kitts (1957).
Orohippus typicus was named by Granger (1908) ["replacement" for Helohippus pumilus].

It was synonymized subjectively with Orohippus pumilus by Lull (1913) and Kitts (1957).

Synonymy list

Year	Name and author
1871	Helotherium procyoninum Cope p. 466
1871	Lophiodon pumilus Marsh p. 38
1871	Lophiotherium ballardi Marsh p. 39
1871	Orohippus pumilus Scott and et al.
1872	Hyrachyus pumilus Leidy
1872	Orohippus pumilus Marsh
1872	Orotherium ballardi Marsh
1873	Oligotomus cinctus Cope p. 2
1874	Orohippus pumilus Marsh p. 249
1875	Orohippus procyoninus Cope p. 22
1877	Hyracotherium procyoninum Cope
1883	Hyracotherium osbornianum Cope p. 647 figs. Plate XXIV; fig. 23
1884	Lambdotherium procyoninum Cope
1884	Pliolophus cinctus Cope
1892	Helohippus pumilus Marsh p. 353
1896	Lambdotherium procyoninum Roger
1896	Pachynolophus ballardi Roger
1896	Pachynolophus cinctus Roger
1896	Pachynolophus pumilus Roger
1896	Orohippus cinctus Wortman
1898	Orohippus osbornianus Trouessart
1899	Helohippus pumilus Matthew
1899	Hyracotherium osbornianum Matthew
1899	Hyracotherium procyoninum Matthew
1899	Orohippus cinctus Matthew
1899	Orohippus pumilus Matthew
1902	Orohippus pumilus Carrano
1902	Helohippus pumilus Hay p. 611
1902	Orohippus ballardi Hay p. 611
1902	Orohippus cinctus Hay p. 611
1902	Orohippus osbornianus Hay p. 611
1902	Orohippus procyoninus Hay p. 612
1908	Hyracotherium osbornianum Granger
1908	Orohippus atavus Granger
1908	Orohippus ballardi Granger
1908	Orohippus pumilus Granger
1908	Orohippus typicus Granger
1909	Orohippus procyoninus Matthew
1930	Orohippus ballardi Hay
1930	Orohippus cinctus Hay
1930	Orohippus osbornianus Hay
1930	Orohippus typicus Hay
1934	Helaletes pumilus Wood
1940	Orohippus ballardi Stirton
1940	Orohippus osbornianus Stirton
1940	Orohippus pumilus Stirton
1940	Orohippus typicus Stirton
1957	Orohippus pumilus Kitts p. 10
1976	Orohippus pumilus Gazin
1998	Orohippus pumilus MacFadden p. 542
2002	Orohippus pumilus Froehlich p. 151

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
—	Osteichthyes	()
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
subclass	Synapsida
—	Therapsida	()
infraorder	Cynodontia	()

Rank	Name	Author
—	Mammaliamorpha
—	Mammaliaformes
class	Mammalia
—	Cladotheria
—	Zatheria
subclass	Tribosphenida	()
subclass	Theria
—	Eutheria	()
—	Placentalia
—	Boreoeutheria
—	Laurasiatheria
—	Scrotifera
—	Euungulata
—	Panperissodactyla
superorder	Perissodactylamorpha
order	Perissodactyla	()
superfamily	Equoidea
family	Equidae
genus	Orohippus
species	pumilus	()

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.

†Orohippus pumilus Marsh 1871

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Invalid names: Helotherium procyoninum Cope 1871 [synonym], Hyracotherium osbornianum Cope 1883 [synonym], Lophiotherium ballardi Marsh 1871 [synonym], Oligotomus cinctus Cope 1873 [synonym], Orohippus atavus Granger 1908 [synonym], Orohippus typicus Granger 1908 [synonym]

Diagnosis

Reference	Diagnosis
D. B. Kitts 1957	Diastema between pI and p2. P2 with lobe-like posterointernal shelf. P3 with acute (50-55º) antero-external angle and ob- tuse (125-130°) antero-internal angle. Mesostyle very weak or absent on P3 and P4. Anterior and posterior borders of P4 parallel and proto- cone distinctly more medial than hypocone. Mesostyle moderate on molars. P4 may be pointed anteriorly. Heel of M3 narrow and sharply constricted anteriorly.

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialsubc

Locomotion:

actively mobilec

Life habit:

ground dwellingf

Diet:

browserf

Reproduction:

viviparoussubc

Created:

2005-06-08 10:11:09

Modified:

2005-08-31 16:55:50

Source: f = family, subc = subclass, c = class, subp = subphylum

References: Carroll 1988, Lillegraven 1979, Hendy et al. 2009, Ji et al. 2002, Nowak 1991

Age range: Bridgerian or 50.30000 to 46.20000 Ma

Collections (32 total)

Time interval	Ma	Country or state	Original ID and collection number
Bridgerian	50.3 - 46.2	USA (Wyoming)	Lophiodon pumilus (16281) Orohippus atavus (16205) Orohippus osbornianus (16136) Orohippus pumilus (16089 16094 16105 16107 16108 16114 16116 16219 16227 type locality: 16228 16232 16262 16263 16269 16291 16300 16302 16303 16306 16309 16315 16321 16330 16336 16339 16353 16355 16441 16504)