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Mesohippus exoletus

Mammalia - Perissodactyla - Equidae

Taxonomy
Anchitherium exoletum was named by Cope (1874). It is a 3D body fossil.

It was synonymized subjectively with Mesohippus bairdi by Osborn and Wortman (1895), Matthew (1899) and Trouessart (1905); it was recombined as Miohippus exoletus by Hay (1902); it was considered a nomen dubium by Osborn (1904), Osborn (1918) and Macdonald (1992); it was recombined as Mesohippus exoletus by Stirton (1940), Scott (1941), Prothero and Shubin (1989) and MacFadden (1998).

Synonyms
Synonymy list
YearName and author
1874Anchitherium exoletum Cope p. 496
1902Miohippus exoletus Hay p. 614
1918Mesohippus trigonostylus Osborn p. 47 figs. Plate 2.5,6. Text Fig. 27
1935Pediohippus trigonostylus Schlaikjer p. 144
1940Mesohippus exoletus Stirton p. 170
1940Mesohippus tribonostylus Stirton p. 170
1941Mesohippus exoletus Scott
1941Pediohippus trigonostylus Scott
1951Mesohippus trigonostylus Macdonald
1989Mesohippus exoletus Prothero and Shubin
1998Mesohippus exoletus MacFadden p. 543

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RankNameAuthor
kingdomAnimalia()
—Bilateria
—EubilateriaAx 1987
—Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
—Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
—Tetrapoda
—Reptiliomorpha
—Anthracosauria
subclassAmphibiosauriaKuhn 1967
—Cotylosauria()
—Amniota
subclassSynapsida
—Therapsida()
infraorderCynodontia()
—Mammaliamorpha
—Mammaliaformes
RankNameAuthor
classMammalia
—Theriamorpha(Rowe 1993)
—Theriiformes()
—Trechnotheria
—Cladotheria
—Zatheria
subclassTribosphenida()
subclassTheria
—Eutheria()
—Placentalia
—Boreoeutheria
—Laurasiatheria
—Scrotifera
—Euungulata
—Panperissodactyla
superorderPerissodactylamorpha
orderPerissodactyla()
superfamilyEquoidea
familyEquidae
subfamilyAnchitheriinae()
genusMesohippus
speciesexoletus()

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.

†Mesohippus exoletus Cope 1874
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Invalid names: Mesohippus trigonostylus Osborn 1918 [synonym]
Diagnosis
ReferenceDiagnosis
H. F. Osborn 1918 (Mesohippus trigonostylus)The specific name M. trigonostylus refers to the progressive triallgular form of the plications of the hypo- style, which is highly distinctive. From the rudiment of the hypostyle on the post-cingulum, as seen in the M. bairdii stage, a cruciform plication extends anteriorly toward the metaloph, branching into an external pli hypostyle and an internal spur (see paratype, dp4, Plate 2.5) which connects with the metaloph. This condition of the hypostyle is very different from that in any other Middle Oligocene species (compare Plate 2.1-8). A somewhat similar condition of the hypostyle is seen in the type of Miohippus validus from the Protoceras zone.
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, Carroll 1988, Hendy et al. 2009, Lillegraven 1979, Ji et al. 2002

Age range: base of the Chadronian to the top of the Orellan or 37.20000 to 33.30000 Ma

Collections (2 total)


Time interval Ma Country or state Original ID and collection number
Chadronian37.2 - 33.9USA (South Dakota) Mesohippus exoletus (17006)
Orellan33.9 - 33.3USA (South Dakota) Mesohippus exoletus (17141)