PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Miohippus

Mammalia - Perissodactyla - Equidae

Taxonomy

Miohippus was named by Marsh (1874). Its type is Miohippus annectens.

It was synonymized subjectively with Mesohippus by Matthew (1899).

It was assigned to Hyracotheriinae by Hay (1902); to Anchitheriinae by MacFadden (1998); and to Equidae by Marsh (1874), Scott (1913), Osborn (1918), Hay (1930), Stirton (1940), Carroll (1988), Prothero and Schoch (1989) and Lofgren et al. (2020).

Species

Anchitherium longicristis, M. anceps, M. annectens (syn. M. crassicuspis) (type species), M. assiniboiensis (syn. Mesohippus planidens), M. condoni, M. equiceps (syn. Anchitherium brachylophum, Mesohippus acutidens), M. equinanus, M. gemmarosae, M. gidleyi (syn. Mesohippus grallipes, M. validus), M. grandis, M. intermedius, M. obliquidens (syn. Mesohippus eulophus, Mesohippus meteulophus, Mesohippus brachystylus, Pediohippus antiquus), M. primus, M. quartus, M. taxus

Synonyms

Altippus was named by Douglass (1908).

It was synonymized subjectively with Parahippus by Osborn (1918) and Hay (1930); it was synonymized subjectively with Miohippus by Schlaikjer (1937), Stirton (1940) and Jahns (1940).
Anchitherium longicristis was named by Cope (1878) [also said to be 1879].

It was recombined as Miohippus longicristis by Cope (1894), Scott (1895), Roger (1896), Trouessart (1898), Hay (1902), Hay (1930) and Stirton (1940); it was recombined as Mesohippus longicristis by Matthew (1899), Osborn (1904) and Merriam and Sinclair (1907); it was considered a nomen dubium by Osborn (1918) and Macdonald (1992).
Pediohippus was named by Schlaikjer (1935). Its type is Pediohippus antiquus.

It was synonymized subjectively with Mesohippus by Stirton (1940); it was synonymized subjectively with Miohippus by Forsten (1974), Prothero and Shubin (1989) and MacFadden (1998).

Synonymy list

Year	Name and author
1874	Miohippus Marsh
1878	Anchitherium longicristis Cope p. 75
1879	Anchitherium longicriste Cope p. 58
1894	Miohippus longicristis Cope p. 791
1895	Miohippus longicristis Scott
1896	Miohippus longicristis Roger
1898	Miohippus longicristis Trouessart
1899	Mesohippus longicristis Matthew
1902	Miohippus Hay p. 612
1902	Miohippus longicristis Hay p. 614
1904	Mesohippus longicristis Osborn p. 168
1907	Mesohippus longicristis Merriam and Sinclair
1908	Altippus Douglass
1913	Miohippus Scott p. 290
1918	Miohippus Osborn
1930	Miohippus Hay
1930	Miohippus longicristis Hay p. 677
1935	Pediohippus Schlaikjer
1940	Miohippus Stirton
1940	Miohippus longicristis Stirton p. 172
1988	Miohippus Carroll
1989	Miohippus Prothero and Schoch p. 531
1998	Miohippus MacFadden p. 544
2020	Miohippus Lofgren et al.

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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
subfamily	Anchitheriinae	()
genus	Miohippus

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.

G. †Miohippus Marsh 1874

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†Miohippus anceps Marsh 1874

†Miohippus annectens Marsh 1874

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Invalid names: Miohippus crassicuspis Osborn 1904 [synonym]

†Miohippus assiniboiensis Lambe 1905

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Invalid names: Mesohippus planidens Lambe 1905 [synonym]

†Miohippus condoni Leidy 1870

†Miohippus equiceps Cope 1878

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Invalid names: Anchitherium brachylophum Cope 1878 [synonym], Mesohippus acutidens Sinclair 1905 [synonym]

†Miohippus equinanus Osborn 1918

†Miohippus gemmarosae Osborn 1918

†Miohippus gidleyi Osborn 1904

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Invalid names: Mesohippus grallipes Sinclair 1925 [synonym], Miohippus validus Osborn 1904 [synonym]

†Miohippus grandis Clark and Beerbower 1967

†Miohippus intermedius Osborn and Wortman 1895

†Miohippus obliquidens Osborn 1904

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Invalid names: Mesohippus brachystylus Osborn 1904 [synonym], Mesohippus eulophus Osborn 1904 [synonym], Mesohippus meteulophus Osborn 1904 [synonym], Pediohippus antiquus Schlaikjer 1935 [synonym]

†Miohippus primus Osborn 1918

†Miohippus quartus Osborn 1918

†Miohippus taxus Douglass 1908

Invalid names: Altippus Douglass 1908 [synonym], Anchitherium longicristis Cope 1878 [nomen dubium], Pediohippus Schlaikjer 1935 [synonym]

Diagnosis

No diagnoses are available

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

Age range: base of the Chadronian to the top of the Harrisonian or 37.20000 to 18.50000 Ma

Collections (86 total)

Time interval	Ma	Country or state	Original ID and collection number
Bartonian - Rupelian	41.3 - 28.1	Mexico (Oaxaca)	M. assinoboiensis (166797)
Chadronian	37.2 - 33.9	USA (Montana)	M. grandis (16959 16988 17010) M. obliquidens (17041) M. sp. (230861)
Chadronian	37.2 - 33.9	USA (South Dakota)	Mesohippus grandis (17006)
Chadronian	37.2 - 33.9	Canada (Saskatchewan)	M. grandis (16919)
Orellan	33.9 - 33.3	Canada (Saskatchewan)	M. grandis (17111) M. sp. (17055)
Orellan	33.9 - 33.3	USA (Colorado)	Mesohippus eulophus (17081 17082)
Orellan	33.9 - 33.3	USA (Wyoming)	M. sp. (17318) Pediohippus antiquus (17117)
Orellan	33.9 - 33.3	USA (Montana)	M. obliquidens (17109)
Orellan	33.9 - 33.3	USA (South Dakota)	Mesohippus grallipes (17296) M. obliquidens (17142) M. sp. (17186 17187 17188 17189 17190)
Oligocene	33.9 - 23.03	USA (Montana)	M. sp. (235274)
Whitneyan	33.3 - 30.8	USA (Colorado)	M. sp. (17426)
Whitneyan	33.3 - 30.8	Canada (Saskatchewan)	M. equiceps (17372)
Whitneyan	33.3 - 30.8	USA (South Dakota)	Mesohippus grallipes, Mesohippus intermedius, Mesohippus validus, M. crassicuspis, M. gidleyi (17344) Mesohippus meteulophus (17343) M. obliquidens (17317) M. sp. (17336 17338 17384)
Whitneyan	33.3 - 30.8	USA (Florida)	Mesohippus sp. (17341)
Whitneyan	33.3 - 30.8	USA (Oregon)	M. sp. (17313 17349)
Whitneyan	33.3 - 30.8	USA (North Dakota)	M. sp. (17320)
Whitneyan - Monroecreekian	33.3 - 24.8	Canada (Saskatchewan)	M. sp., M. assiniboiensis, M. intermedius (17306)
Whitneyan - Monroecreekian	33.3 - 24.8	USA (North Dakota)	M. obliquidens (17330)
Whitneyan - late Early Arikareean	33.3 - 18.5	USA (California)	M. sp. (17527)
Geringian	30.8 - 26.3	USA (Nebraska)	M. intermedius (17494 17495)
Geringian	30.8 - 26.3	USA (Oregon)	M. sp. (17508 93078) M. sp., Anchitherium brachylophum, Anchitherium equiceps, M. intermedius, M. primus (17537)
Geringian	30.8 - 26.3	USA (South Dakota)	M. equiceps (17623 17627 17634 17635 17638 17641) M. equiceps, M. equinanus (17626 17636) M. equinanus (17630)
Geringian - Monroecreekian	30.8 - 24.8	USA (Florida)	M. sp. (17487)
Arikareean	29.5 - 18.5	USA (California)	M. sp. (17701)
Arikareean	29.5 - 18.5	USA (Montana)	M. anceps, M. annectens, M. equiceps (17509) M. sp. (17481 17543 17700)
Arikareean	29.5 - 18.5	USA (Wyoming)	M. sp. (17667)
Arikareean	29.5 - 18.5	USA (Oregon)	Anchitherium longicriste (180202) M. sp. (93080 170311)
Arikareean	29.5 - 18.5	USA (Idaho)	M. gemmarosae (17586)
Arikareean	29.5 - 18.5	USA (Nebraska)	M. intermedius (17568) M. sp. (17538)
Arikareean	29.5 - 18.5	USA (South Dakota)	M. brachystylus (17520) M. equinanus (17447 17460 17461)
Arikareean	29.5 - 18.5	USA (Florida)	M. sp. (17476)
early Early Arikareean	29.5 - 18.5	USA (Nebraska)	M. sp. (156729)
early Late Arikareean	29.5 - 18.5	USA (Oregon)	M. sp. (36761)
Chattian	28.1 - 23.03	USA (Oregon)	M. sp. (17603 93079)
Monroecreekian	26.3 - 24.8	Canada (Saskatchewan)	M. sp. (17526)
Monroecreekian	26.3 - 24.8	USA (Washington)	M. sp. (119840) M. sp., M. equiceps, M. equinanus (119838)
Monroecreekian	26.3 - 24.8	USA (South Dakota)	Archaeohippus equinanus (17723) M. equinanus (17564) M. gemmarosae (17545)
Monroecreekian - Harrisonian	26.3 - 18.5	USA (Oregon)	M. sp. (17528)
Harrisonian	24.8 - 18.5	USA (Montana)	Altippus taxus (17861)
Harrisonian	24.8 - 18.5	USA (South Dakota)	M. equinanus, M. gemmarosae (17451)
Harrisonian	24.8 - 18.5	Canada (Saskatchewan)	M. gemmarosae (17758)
Aquitanian	23.03 - 20.44	USA (Texas)	M. sp. (18663)
Hemingfordian	20.43 - 15.97	Canada (Saskatchewan)	M. sp. (18002)