PBDB Taxon

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Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Equus francisci

Mammalia - Perissodactyla - Equidae

Taxonomy

Equus francisci was named by Hay (1915) [NOT E. francisi, a misspelling; also said to be 1913]. Its type specimen is TAMU 2518, a partial skeleton, and it is a 3D body fossil.

It was synonymized subjectively with Equus conversidens by Hay (1915), Hibbard (1939), Hibbard and Taylor (1960), Dalquest and Hughes (1965); it was recombined as Asinus francisci by Quinn (1955) and Hibbard (1958); it was synonymized subjectively with Equus (Hemionus) tau by Dalquest (1979); it was synonymized subjectively with Equus tau by Kurten and Anderson (1980); it was recombined as Haringtonhippus francisci by Heintzman et al. (2017).

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 arrelanoi was named by Mooser (1958).

It was synonymized subjectively with Equus francisci by Winans (1989).
Equus (Asinus) calobatus was named by Troxell (1915) [lectotype selected by Hibbard 1953 from syntypic series of Troxell]. Its type specimen is YPM 13470, a limb element (left metatarsal), and it is a 3D body fossil. Its type locality is head of Rock Creek, Mayfield Ranch, which is in an Irvingtonian terrestrial horizon in the Tule Formation of Texas.

It was recombined as Equus calobatus by Troxel (1915), Kurten and Anderson (1980); it was synonymized subjectively with Onager semiplicatus by Quinn (1957); it was recombined as Equus (Hemionus) calobatus by Skinner (1972); it was synonymized subjectively with Equus semiplicatus by Schultz (1990); it was synonymized subjectively with Equus francisci by Harris (1993); it was synonymized subjectively with Equus (Dolichohippus) simplicidens by MacFadden (1998).
Equus quinni was named by Slaughter et al. (1962). It is not a trace fossil.

It was synonymized subjectively with Equus (Hemionus) tau by Dalquest (1979); it was synonymized subjectively with Equus tau by Kurten and Anderson (1980); it was synonymized subjectively with Equus francisci by Lundelius and Stevens (1970), Lundelius (1972), Winans (1989).

Synonymy list

Year	Name and author
1915	Equus francisci Hay
1915	Equus calobatus Troxel
1915	Equus (Asinus) calobatus Troxell p. 615 fig. 4
1955	Asinus francisci Quinn p. 52
1958	Asinus francisci Hibbard
1958	Equus arrelanoi Mooser
1962	Equus quinni Slaughter et al.
1966	Equus quinni Slaughter p. 89
1970	Equus francisci Lundelius and Stevens p. 152
1972	Equus (Hemionus) calobatus Skinner p. 124
1980	Equus calobatus Kurten and Anderson p. 288
1984	Equus francisci Lundelius, Jr.
1992	Equus (Asinus) calobatus Dalquest and Schultz
1993	Equus francisci Harris
1995	Equus francisci Hulbert, Jr.
2007	Equus francisci Morgan and Rinehart p. 40
2017	Haringtonhippus francisci Heintzman et al. p. 5
2019	Equus francisci Barrón-Ortiz et al. p. 9

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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	francisci

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 francisci Hay 1915

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Invalid names: Equus (Asinus) calobatus Troxell 1915 [synonym], Equus arrelanoi Mooser 1958 [synonym], Equus quinni Slaughter et al. 1962 [synonym]

Diagnosis

Reference	Diagnosis
P. D. Heintzman et al. 2017	Haringtonhippus is the sister genus to Equus (equid crown group), with Hippidion being sister to the Haringtonhippus-Equus clade (Figure 1). Haringtonhippus can be differentiated from Equus and Hip- pidion by 178 synapomorphic positions in the mitochondrial genome, including four insertions and 174 substitutions (Appendix 1—Table 2 and Appendix 1—table 2—source data 1). We caution that these synapomorphies are tentative and will likely be reduced in number as a greater diversity of mitochondrial genomes for extinct equids become available.