PBDB Taxon

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

Pliohippus

Osteichthyes - Perissodactyla - Equidae

Taxonomy

Pliohippus was named by Marsh (1874). Its type is Pliohippus pernix.

It was synonymized subjectively with Hippidium by Cope (1879); it was synonymized subjectively with Protohippus by Gidley (1903), Gidley (1904).

It was assigned to Protohippinae by Gidley (1907); to Protohippini by Quinn (1955); to Equinae by Hay (1902), Forsten (1975); to Equidae by Marsh (1874), Scott (1913), Matthew and Stirton (1930), Stirton (1940), Webb (1969), Carroll (1988), Hulbert (1989); to Pliohippina by Prado and Alberdi (1996); and to Equini by Prothero and Schoch (1989), Kelly (1995), MacFadden (1998), Ferrusquía-Villafranca et al. (2014).

Species

P. (Astrohippus), P. (Pliohippus), P. bakeri, P. coalingensis, P. fossulatus (syn. Protohippus pachyops), P. gracilis, P. mirabilis (syn. Merychippus campestris), P. nobilis, P. pernix (syn. P. robustus, P. lullianus) (type species), P. potosinus, P. tantalus (syn. P. fairbanksi), P. tehonensis

Synonyms

Pliohippus gracilis was named by Marsh (1892). Its type specimen is YPM 11301, a set of limb elements (a right foot and a few other bones), and it is a 3D body fossil.

It was recombined as Kalobatippus gracilis by Osborn (1918), MacFadden (1998); it was recombined as Anchitherium gracilis by Stirton (1940); it was considered a nomen dubium by Gidley (1907); it was considered a nomen vanum by Romer (1926), Macdonald (1992); it was synonymized subjectively with Kalobatippus praestans by MacFadden (2001).

Synonymy list

Year	Name and author
1874	Pliohippus Marsh
1892	Pliohippus gracilis Marsh p. 347
1902	Pliohippus Hay p. 618
1902	Pliohippus gracilis Hay p. 618
1907	Pliohippus Gidley p. 867
1913	Pliohippus Scott p. 290
1918	Kalobatippus gracilis Osborn p. 71 figs. Text Figs. 49, 51
1930	Pliohippus Matthew and Stirton
1940	Pliohippus Stirton
1940	Anchitherium gracilis Stirton p. 174
1955	Pliohippus Quinn p. 13
1969	Pliohippus Webb
1975	Pliohippus Forsten p. 48
1988	Pliohippus Carroll
1989	Pliohippus Hulbert, Jr.
1989	Pliohippus Prothero and Schoch p. 532
1995	Pliohippus Kelly p. 14
1996	Pliohippus Prado and Alberdi p. 676
1998	Kalobatippus gracilis MacFadden
1998	Pliohippus MacFadden p. 550
2014	Pliohippus Ferrusquía-Villafranca et al. p. 204

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

Rank	Name	Author
—	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	Equinae
tribe	Equini
genus	Pliohippus

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. †Pliohippus Marsh 1874

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Subg. †Pliohippus (Astrohippus) Stirton 1940

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†Pliohippus (Astrohippus) stockii Lance 1950

Subg. †Pliohippus (Pliohippus) Stirton 1940

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†Pliohippus (Pliohippus) mexicanus Lance 1950

†Pliohippus bakeri Azzaroli 1988

†Pliohippus coalingensis Merriam 1914

†Pliohippus fossulatus Cope 1893

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Invalid names: Protohippus pachyops Cope 1893 [synonym]

†Pliohippus mirabilis Leidy 1858

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Invalid names: Merychippus campestris Gidley 1907 [synonym]

†Pliohippus nobilis Osborn 1918

†Pliohippus pernix Marsh 1874

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Invalid names: Pliohippus lullianus Troxell 1916 [synonym], Pliohippus robustus Marsh 1874 [synonym]

†Pliohippus potosinus Ferrusquía-Villafranca et al. 2014

†Pliohippus tantalus Merriam 1913

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Invalid names: Pliohippus fairbanksi Merriam 1915 [synonym]

†Pliohippus tehonensis Merriam 1915

Invalid names: Pliohippus gracilis Marsh 1892 [nomen dubium]

Diagnosis

Reference	Diagnosis
J. H. Quinn 1955	sence of malar fossa; strongly curved upper cheek teeth; flat- tened entoconid with shallow valleys, prominent ribs and reduced styles with the parastyles of the premolars little or no larger than those of the molars; small, round to oval protocones; postprotoconal valleys shallow; hypoconal grooves partly closed; metaconids and metastylids round- ed, not widely separated, and nearly equal in size; no· pli caballinds; parastylids faint and oriented as in Hippodon; proto- conids and hypoconids transversely broad and markedly rounded; metapodials short, lateral digits present in earlier species but probably lost in later species.

Measurements

No measurements are available

Composition:

phosphaticsubp

Environment:

terrestrialsubc

Locomotion:

actively mobilec

Life habit:

ground dwellingsubf

Diet:

browserg

Reproduction:

viviparoussubc

Comments:

browser based on stable isotopes (MacFadden and Cerling 1996)g

Created:

2009-01-04 10:28:26

Modified:

2009-01-04 12:28:26

Source: g = genus, subf = subfamily, subc = subclass, c = class, subp = subphylum

References: Hendy et al. 2009, Carroll 1988, MacFadden 1998, Nowak 1991, Ji et al. 2002, Lillegraven 1979, MacFadden and Cerling 1996

Age range: base of the Langhian to the top of the Hemphillian or 15.98000 to 4.70000 Ma

Collections (151 total)

Time interval	Ma	Country or state	Original ID and collection number
Miocene	23.04 - 5.333	USA (Nevada)	P. sp. (18885 19040) P. tantalus (19125)
Miocene	23.04 - 5.333	USA (South Dakota)	P. lullianus (18297 18384 18388 18395)
Miocene	23.04 - 5.333	USA (Texas)	P. pernix (18103)
Miocene	23.04 - 5.333	USA (Nebraska)	P. sp. (18213)
Miocene	23.04 - 5.333	USA (Montana)	P. sp. (18812)
Miocene	23.04 - 5.333	USA (California)	P. tehonensis (19148 19149)
Miocene	23.04 - 5.333	USA (Colorado)	P. sp., Merychippus campestris (18310)
Barstovian	16.3 - 12.5	USA (New Mexico)	P. pernix (19435) P. sp. (19287 19519 19535)
Barstovian	16.3 - 12.5	USA (Nebraska)	P. mirabilis (18124 18164 18206 18281 18442) P. sp. (18121 18123 18192) Protohippus sp. (18199 18240)
Barstovian	16.3 - 12.5	USA (Colorado)	P. mirabilis (18203)
Barstovian	16.3 - 12.5	USA (Florida)	P. mirabilis (18583)
Barstovian	16.3 - 12.5	USA (Texas)	P. sp. (207493)
Barstovian - Clarendonian	16.3 - 9.4	USA (Nebraska)	P. pernix (18077) P. supremus (18235)
Barstovian - Early/Lower Clarendonian	16.3 - 9.4	USA (Kansas)	P. sp. (18187)
Langhian	15.98 - 13.82	USA (Florida)	P. pernix (18569)
Clarendonian	12.5 - 9.4	USA (Texas)	P. fossulatus (18149 18244 18355) P. fossulatus, P. pernix (18347) P. pernix (18104 18179 18640) P. sp. (18096 18610 207452 207489)
Clarendonian	12.5 - 9.4	USA (South Dakota)	P. lullianus (18406) P. pernix (18063 18428) P. sp. (18268)
Clarendonian	12.5 - 9.4	USA (Nebraska)	P. pernix (18042 18092 18176 18204 18217 18222 18233 18242 18251 18260 18324 18334 18466 18483 188779) P. sp. (18221 18314 18315) P. supremus (18082)
Clarendonian	12.5 - 9.4	USA (Nevada)	P. tantalus (18845 18888)
Clarendonian	12.5 - 9.4	USA (Kansas)	P. sp. (18219)
Clarendonian	12.5 - 9.4	USA (Oklahoma)	P. pernix (18130) P. sp. (18463)
Clarendonian	12.5 - 9.4	USA (California)	P. fairbanksi, P. tehonensis (19517) P. sp. (19145 19277 19353 19453 19501 19503 19504 19505 19507) P. tantalus (19383 19384) P. tantalus, P. tehonensis (19322) P. tehonensis (19182 19276 19278 19310 19317 19361 19378 19467 19486 19487 19488 19489 19492 19494 19495 19496 19497 19499 19500 19508 19512 19541 19553 19592 19593 19594)
Early/Lower Clarendonian	12.5 - 9.4	USA (Florida)	P. pernix (161374)
Late/Upper Clarendonian	12.5 - 9.4	USA (Kansas)	P. pernix (110829)
Late/Upper Clarendonian	12.5 - 9.4	USA (New Mexico)	P. sp., P. pernix (19528)
Late/Upper Clarendonian	12.5 - 9.4	USA (Nebraska)	P. pernix (18066)
Clarendonian - Hemphillian	12.5 - 4.7	USA (Nebraska)	P. nobilis (18305) P. pernix (18236 18295)
Late/Upper Clarendonian - late Early Hemphillian	12.5 - 4.7	USA (Nebraska)	P. sp. (18298)
Clarendonian - Pliocene	12.5 - 2.58	USA (Oklahoma)	P. pernix (170181)
Tortonian	11.63 - 7.246	USA (Florida)	P. mirabilis (18509)
Late/Upper Miocene	11.63 - 5.333	Mexico (San Luis Potosí)	P. potosinus (173691)
Late/Upper Miocene	11.63 - 5.333	USA (Oregon)	P. sp. (154947)
Late/Upper Miocene - Early/Lower Pliocene	11.63 - 3.6	USA (California)	P. tantalus (19468)
Late/Upper Miocene - Pliocene	11.63 - 2.58	USA (California)	P. sp. (19377)
Hemphillian	9.4 - 4.7	USA (Texas)	P. bakeri (18097) P. nobilis (18072 18198) P. sp. (18211)
Hemphillian	9.4 - 4.7	USA (Nebraska)	P. nobilis (18225)
Hemphillian	9.4 - 4.7	USA (Oklahoma)	P. nobilis (18034)
Hemphillian	9.4 - 4.7	USA (Kansas)	P. nobilis (18237)
Hemphillian	9.4 - 4.7	USA (California)	P. coalingensis (19537) P. sp. (19342 19394 19395 19396 19397 19398 19399 19400 19401 19402 19403 19404 19406 19407 19408)
Early/Lower Pliocene	5.333 - 3.6	USA (California)	Protohippus coalingensis (178905 178908)