Editing Onager (section)

==Evolution==
{{see also|Evolution of the horse}}
[[File:Equus eisenmannae.JPG|thumb|Skull of a giant extinct horse, ''Equus eisenmannae'']]
The genus ''Equus'', which includes all extant equines, is believed to have evolved from ''[[Dinohippus]]'' via the intermediate form ''[[Plesippus]]''. One of the oldest species is ''[[Hagerman Horse|Equus simplicidens]]'', described as zebra-like with a donkey-shaped head. The oldest fossil to date is about 3.5 million years old from Idaho, USA. The genus appears to have spread quickly into the Old World, with the similarly aged ''Equus livenzovensis'' documented from western Europe and Russia.<ref name = "Azzaroli1992">{{cite journal |last=Azzaroli |first=A. |year=1992 |title=Ascent and decline of monodactyl equids: a case for prehistoric overkill |journal=Ann. Zool. Finnici |volume=28 |pages=151–163 |url=http://www.sekj.org/PDF/anzf28/anz28-151-163.pdf}}</ref>

Molecular phylogenies indicate the most recent common ancestor of all modern equids (members of the genus ''Equus'') lived around 5.6 (3.9–7.8) million years ago (Mya). Direct paleogenomic sequencing of a 700,000-year-old middle Pleistocene horse metapodial bone from Canada implies a more recent 4.07''&nbsp;''Mya for the most recent common ancestor within the range of 4.0 to 4.5''&nbsp;''Mya.<ref name="ReferenceA">{{cite journal |title=Recalibrating ''Equus evolution'' using the genome sequence of an early Middle Pleistocene horse |last1=Orlando|first1= L.|last2=Ginolhac|first2= A.|last3=Zhang|first3= G.|last4=Froese|first4= D.|last5=Albrechtsen|first5= A.|last6=Stiller|first6= M.|last7=Schubert|first7= M.|last8=Cappellini|first8= E.|last9=Petersen|first9= B.|journal=Nature|date=4 July 2013 |doi=10.1038/nature12323 |pmid=23803765 |volume=499 |issue=7456 |pages=74–8|bibcode=2013Natur.499...74O|s2cid=4318227|display-authors=etal}}</ref> The oldest divergencies are the Asian hemiones (subgenus ''E. ([[Asinus]])'', including the [[Turkmenian kulan|kulan]], onager, and [[kiang]]), followed by the African zebras (subgenera ''E. ([[Dolichohippus]])'', and ''E. ([[Hippotigris]])''). All other modern forms including the domesticated horse (and many fossil [[Pliocene]] and [[Pleistocene]] forms) belong to the subgenus ''E. ([[Equus (genus)|Equus]])'' which diverged about 4.8 (3.2–6.5) Mya.<ref name = "WeinstockMolecularPerspective"/>