Belongs within: Equinae.
Hipparion is a diverse genus of three-toed horses known from the Miocene to the Pleistocene of Eurasia, Africa and North America.
Characters (from Churcher & Richardson 1978): Facial region relatively short and deep; preorbital fossae present or absent; sagittal crest low; bony auditory meatus long and directed dorsolaterally; basicranial region usually with prominent longitudinal crest; occiput with deep fossae above occipital condyles for attachment of nuchal musculature. Coronoid process of dentary high; ascending ramus vertical. Incisors large, cement filled; infundibula typically present on upper and lower I1 and I2; in I3 infundibulum closed or partly closed. Canines usually present in both sexes, possibly dimorphic. Cheek teeth moderately to very hypsodont, slightly bowed, prismatic. Upper cheek teeth with isolated, more or less elongate protocones, almost always with many plis in fossettes. Lower cheek teeth with well-developed double loop, metaflexid with subequal arms and deep median valley; M3 usually with tripartite talonid; well-developed ectostylid in milk lower cheek teeth of all forms where known and in permanent lower cheek teeth of more derived forms. Limbs with angled joints, ulna complete. Metapodials moderately to very elongate; metapodials III with traces of II and IV contacts along shafts; metapodials II and IV variably developed, apparently without reduction in size through time; vestigial metacarpal V present. Digits II, III and IV functional but II and IV shorter and thinner than III. Terminal phalanges (ungules) cut by deep median slit.
<==Hipparion de Christol 1832F99 (see below for synonymy) |--H. sitifense Pomel 1897 [=H. sitifensis]CR78 | |--H. s. sitifenseCR78 | `--H. s. gromovae Villalta & Crusafont 1957CR78 |--H. turkanense Hooijer & Maglio 1973CR78 `--+--H. primigenium (von Meyer 1829) [=Equus primigenius; incl. H. gracile]CR78 `--+--+--H. baardi Boné & Singer 1965 [=H. (Hipparion) albertense baardi]CR78 | `--H. namaquense (Haughton 1932) [=Notohipparion namaquense]CR78 `--+--H. afarense Eisenmann 1976CR78 `--H. libycum Pomel 1897 (see below for synonymy)CR78 |--H. l. libycumCR78 |--H. l. ethiopicum (Joleaud 1933) [=Libyhipparion ethiopicum]CR78 `--H. l. steytleri van Hoepen 1930 [=Libyhipparion steytleri, Stylohipparion steytleri]CR78 Hipparion incertae sedis: H. africanum Arambourg 1959F99 H. antelopinum Falconer & Cautley 1847F99 H. anthonyiD07 H. brachypus Hensel 1862F99 H. campbelli Bernor 1985F99 H. catalaunicum Pirlot 1956F99 H. chiaiDW04 H. coelophyesDW04 H. concudenseD07 H. dermatorhinum Sefve 1927F99 H. dongxiangenseDW04 H. elegans Gromova 1952F99 H. fossatum Sefve 1927F99 H. garedzicum Gabuniya 1959F99 H. gettyi Bernor 1985F99 H. giganteum Gromova 1952F99 H. hippidiodus Sefve 1927 [incl. H. platygenys Gromova 1952]F99 H. houfenenseDW04 H. huangheenseD07 H. licenti Qiu, Huang & Guo 1987F99 H. macedonicum Koufos 1984F99 H. matthewi Abel 1926F99 H. mediterraneum (Roth & Wagner 1855)F99 H. microtaton Nikolov 1971F99 H. mogoicum Zhegallo 1978F99 H. mohavenseD07 H. molayanense Zouhri 1992F99 H. moldavicum Gromova 1952F99 H. nesebricum Bakalov & Nikolov 1962F99 H. nicosi Bernor & Tobien 1989F99 H. parvumDW04 H. periafricanum Villalta & Crusafont 1957F99 H. platystyleD07 H. plocodus Sefve 1927F99 H. praegiganteum Tarabukin 1967F99 H. presulcatum Nikolov 1971F99 H. proboscideum Studer 1911F99 H. prostylum Gervais 1849F99 H. sarmaticum Lungu 1973F99 H. schlosseri Antonius 1919 [incl. Hemihipparion dietrichi Wehrli 1941, Hi. dietrichi]F99 H. shirleyi MacFadden 1984F99 H. sinenseDW04 H. tchicoicum Ivanjev 1966F99 H. tudorovense Gabuniya 1959F99 H. urmiense Gabuniya 1959F99 H. verae Gabuniya 1979 [=H. gromovae Gabuniya 1959 non Villalta & Crusafont 1957]F99 H. weihoense Liu, Li & Zhai 1978F99
Hipparion de Christol 1832F99 [incl. Eurygnathohippus van Hoepen 1930CR78, Libyhipparion Joleaud 1933CR78, Notohipparion Haughton 1932CR78, Stylohipparion van Hoeppen 1932CR78]
Hipparion libycum Pomel 1897 [=H. (Stylohipparion) libycum; incl. H. albertensis Hopwood 1926 (n. d.), H. albertense, Stylohipparion albertense, H. ambiguum Pomel 1897, Eurygnathohippus cornelianus van Hoepen 1930, Stylohipparion hipkini van Hoepen 1932, Hipparion massoesylium Pomel 1897, H. (Hipparion) albertense serengetense Boné & Singer 1965]CR78
*Type species of generic name indicated
References
[CR78] Churcher, C. S., & M. L. Richardson. 1978. Equidae. In: Maglio, V. J., & H. B. S. Cooke (eds) Evolution of African Mammals pp. 379–422. Harvard University Press: Cambridge (Massachusetts).
[DW04] Deng T., Wang X., Ni X. & Liu L. 2004. Sequence of the Cenozoic mammalian faunas of the Linxia Basin in Gansu, China. Acta Geologica Sinica (English Edition) 78 (1): 8–14.
[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.
[F99] Forsten, A. 1999. Snout proportions in some Eurasian hipparions (Mammalia, Equidae): taxonomic and functional implications. Geodiversitas 21 (2): 255–278.