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Hyracotherium angustidens grangeri

Osteichthyes - Perissodactyla - Equidae

Taxonomy
Hyracotherium angustidens grangeri was named by Kitts (1956) [raised to species level]. Its type specimen is AMNH 16134, a maxilla (fragment of maxilla with P3-M3), and it is a 3D body fossil.

It was recombined as Hyracotherium grangeri by Gingerich (1989), MacFadden (1998), Wood et al. (2011); it was recombined as Arenahippus grangeri by Froehlich (2002); it was recombined as Sifrhippus grangeri by Secord et al. (2012).

Entered
by J. Marcot on 2026-04-17; modified by J. Marcot on 2026-04-17

Synonymy list
YearName and author
1956Hyracotherium angustidens grangeri Kitts p. 42
1989Hyracotherium grangeri Gingerich p. 62
1998Hyracotherium grangeri MacFadden p. 542
2002Arenahippus grangeri Froehlich pp. 165-169
2011Hyracotherium grangeri Wood et al. p. 2
2012Sifrhippus grangeri Secord et al. p. 962

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
classOsteichthyes
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
subclassSynapsida
Therapsida()
infraorderCynodontia()
Mammaliamorpha
RankNameAuthor
Mammaliaformes
classMammalia
Cladotheria
Zatheria
subclassTribosphenida()
subclassTheria
Eutheria()
Placentalia
Boreoeutheria
Laurasiatheria
Scrotifera
Euungulata
Panperissodactyla
superorderPerissodactylamorpha
orderPerissodactyla()
superfamilyEquoidea
familyEquidae
genusHyracotherium
speciesangustidens()
subspeciesgrangeri

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.

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Diagnosis
ReferenceDiagnosis
D. J. Froehlich 2002This taxon lacks any unambiguous autapomorphies but the clade composed of Arenahippus grangeri and all more-derived equids is uniquely diagnosed by the presence of P4 posterior ridge moderate (Character 76, 0 to 1), premolar paralophid complex very short (Character 79, 1 to 0), and molar paracristid bend rounded (Character 88, 1 to 0), but lacks a single medial cusp on the P2 (Character 21, 0 to 1), and a moderate M3 hypolophid (Character 104, 0 to 1), the synapomorphies of the next more-derived equid clade.
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: Ji et al. 2002, Nowak 1991, Lillegraven 1979, Carroll 1988, Hendy et al. 2009
Collections
No collection or age range data are available