PBDB Taxon

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

Equus conversidens

Mammalia - Perissodactyla - Equidae

Taxonomy

Equus conversidens was named by Owen (1869) [holotype is IGM 4008?? ]. Its type specimen is IGM 403, a partial skull ( the maxillaries and part of the palate, with right and left P2-M3, of a small young adult horse), and it is a 3D body fossil.

It was synonymized subjectively with Equus tau by Cope (1884), Miller (1976); it was recombined as Asinus conversidens by Quinn (1957); it was recombined as Equus (Hemionus) conversidens by Skinner (1972); it was synonymized subjectively with Equus alaskae by Harris (1993).

Sister species lacking formal opinion data

E. algericus, E. altidens, E. bressanus, E. ferus, E. germanicus, E. helmei, E. hydruntinus, E. livenzovensis, E. marxi, E. mauritanicus, E. mosbachensis, E. namadicus, E. petraloniensis, E. robustus, E. simionescui, E. stehlini, E. valeriani, E. verae, E. helmei, E. koobiforensis, E. oldowayensis

Synonyms

Equus barcenaei was named by Cope (1884) [type not designated (Dalquest 1979)]. It is a 3D body fossil. Its type locality is Tequixquiac, which is in a Pliocene terrestrial horizon in Mexico.

It was synonymized subjectively with Equus tau by Cope (1893), Gidley (1901), Hay (1902) and Trouessart (1905); it was synonymized subjectively with Equus conversidens by Hibbard (1955), Dalquest and Hughes (1965), Dalquest (1979).
Onager zoyatalis was named by Mooser (1959). It is not a trace fossil.

It was synonymized subjectively with Equus conversidens by Mooser and Dalquest (1975), Dalquest (1979); it was synonymized subjectively with Equus francisci by Lundelius and Stevens (1970), Winans (1989).

Synonymy list

Year	Name and author
1869	Equus conversidens Owen
1884	Equus barcenaei Cope p. 15
1901	Equus conversidens Gidley p. 118
1902	Equus conversidens Hay p. 623
1924	Equus barcenaei Hay
1930	Equus barcenaei Hay
1942	Equus conversidens Skinner
1955	Equus conversidens Hibbard
1957	Asinus conversidens Quinn
1959	Onager zoyatalis Mooser
1960	Equus conversidens Hibbard and Taylor
1964	Equus conversidens Dalquest
1965	Equus conversidens Dalquest and Hughes
1966	Equus conversidens Slaughter p. 89
1970	Equus conversidens Lundelius and Stevens p. 152
1972	Equus (Hemionus) conversidens Skinner p. 125
1979	Equus conversidens Dalquest p. 241
1980	Equus conversidens Kurten and Anderson p. 291
1987	Equus conversidens Carranza-Castaneda and Miller p. 338
2005	Equus conversidens Cisneros p. 249
2007	Equus conversidens Morgan and Rinehart p. 44
2014	Equus conversidens Alberdi 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	()
—	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	Equus
species	conversidens	Owen 1869

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.

†Equus conversidens Owen 1869

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Invalid names: Equus barcenaei Cope 1884 [synonym], Onager zoyatalis Mooser 1959 [synonym]

Diagnosis

Reference	Diagnosis
M. T. Alberdi et al. 2014	The skull fragment IGM4008 (Holotype; No. 403 old number) is constituted mostly by the rostral portion, with the maxilla and teeth in situ. Each dental series includes three molars and three premolars. The premolars exceed the true molars in size (pl. LXI, fig. 1; Owen, 1869). The upper cheek teeth are middle in size, with elongate flattened protocones, derived features and average complexly plicate enamel similar to E. mexicanus but smaller in size. Lower molars have similar morphology but smaller in size than E. mexicanus teeth. Following Winans (1989), the ratio of length to proximal width is generally less than 5.0 for metacarpals and 6.0 for metatarsals. Metapodials are not stilt-legged. The body mass from MCIII13 is between 215.63 to 282.52 kg and the mean is 249.08 kg.