Equus caballus Linnaeus 1758

Wilson, Don E. & Reeder, DeeAnn, 2005, Order Perissodactyla, Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 1, Baltimore: The Johns Hopkins University Press, pp. 629-636 : 630

Equus caballus Linnaeus 1758

Equus caballus Linnaeus 1758 , Syst. Nat., 10th ed., Vol. 1: 73.

Type Locality: "Habitat in Europa" (= Sweden?); based on domestic horses.

Vernacular Names: Horse.

Subspecies: :

Subspecies Equus caballus subsp. caballus Linnaeus 1758

Subspecies Equus caballus subsp. ferus Boddaert 1785

Subspecies Equus caballus subsp. przewalskii Poliakov 1881

Distribution: In the late 18th Century, from Poland and Russian Steppes east to Turkestan and Mongolia; wild population survived (at least until recently) in SW Mongolia and adjacent Gansu, Sinkiang, and Inner Mongolia ( China); reintroduced into Mongolia. Domesticated worldwide; feral in Portugal, Spain, France, Greece, Iran, Sri Lanka, Lesser Sundas ( Flores and Rintja), Australia, New Zealand, Colombia, Hispaniola, Canada, USA (incl. Hawaiian Isls), Galapagos and probably other oceanic islands.

Conservation: CITES – Appendix I as E. przewalskii ; U.S. ESA – Endangered as E. przewalskii ; IUCN – Extinct in the Wild as E. ferus and E. f. przewalskii .

Discussion: Reviewed by Bennett and Hoffman (1999, Mammalian Species, 628). Recent caballine horses have been assigned to two different species, E. caballus (or ferus ) and E. przewalskii , but many authors now include przewalskii in caballus ; see Corbet (1978 c:194), Groves (1974 a), Bennett (1980), and Bennett and Hoffman (1999). Gromov and Baranova (1981:333-334) continued to recognize two species, gmelini (= ferus ) and przewalskii . Groves (1971 b) and Corbet (1978 c:194) proposed that ferus (the Tarpan) replace caballus , objecting to the use of specific names based on domestic animals. Gentry et al. (1996) proposed that majority usage be confirmed by adoption of the first available specific name based on a wild population for the wild taxon, in this case deemed to be E. ferus . It has not been demonstrated that most authors have termed wild horses E. ferus rather than E. caballus or E. c. ferus or other names. Azzaroli (1984), Bennett and Hoffman (1999), and Forsten (1988) are among those who have used the name caballus for the species. The case is complicated by the very much wider use of przewalskii as a name for wild horses, though przewalskii is commonly treated as a species separate from E. caballus . Gentry et al. (1996) asked the International Commission on Zoological Nomenclature to use its plenary power to rule that the name for the wild species is not invalid by virtue of being antedated by the name based on the domestic form. The Commission has ruled in favor of the proposal (International Commission on Zoological Nomenclature, 2003). It has stipulated that ferus is not invalid but has not specified explicitly what name is to be used for the species by those who consider E. caballus and E. ferus to be conspecific (see Bock, 1997). Material evidence that ferus is a distinct form of wild horse is limited to osteological material of two specimens and it has not been reliably identified with Pleistocene or Holocene local populations ( Forsten, 1988). Its status as a wild rather than a feral form is disputed (e.g. Epstein, 1971) and it is not regarded as ancestral to domestic horses by Kuz'mina (1997). Accordingly ferus is here treated as a subspecies of E. caballus . The systematics of ferus needs to be more thoroughly reviewed. Equus ferus Boddaert, 1785 is preoccupied by Equus asinus ferus Erxleben, 1777 (= Equus hemionus ), cited also by Kerr (1792) and G. Fischer [von Waldheim] (1814), which can however be regarded as a nomen oblitum. The next published name, equiferus Pallas, 1811 is available, contrary to Heptner et al. (1961). It is listed by Pallas (1811:510) as " EQUUS Caballus … b. Equiferus" in his synonymy, that is as an infraspecific category, now regarded as a nominal subspecies. For domesticated horses, Desmarest (1822) employed 25 subspecific names and Fitzinger (1858, 1859, 1860) used 160 names for species, subspecies and infrasubspecific categories. Most of these names have been ignored but the specific and subspecific names are available and take part in synonymy. Only those that have been used elsewhere as junior or senior synonyms are cited above, under "synonymy".