''Equus conversidens'', or the Mexican horse, was a

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...

, now extinct, that inhabited

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

of ''Equus conversidens'', a partial palate, was unearthed in Pleistocene deposits northeast of Mexico City,

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. In January 1963, a partial skeleton was found in the city of

Canyon, Texas Canyon is a city in and the county seat of Randall County, Texas, United States. The population was 14,836 at the 2020 United States census, 2020 census. It is part of the Amarillo, Texas, Amarillo metropolitan area, metropolitan statistical area ...

in a white clay bed during the excavation of a basement, and was referred to ''E. conversidens'' by Dalquest and Hughes (1965), who interpreted the species as medium to small-sized, and added additional records of the species from

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

(including a skeleton from Slaton),

Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

and

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

, synonymizing '' Equus francisci'', ''Equus tau'', ''E. littoralis'', ''E. achates'', and ''E. barcenaei'' with ''E. conversidens''.

Criticism

Winans (1985) and MacFadden (1992) challenged the validity of ''E. conversidens'' due to its minimal diagnostic value, and treated ''E. francisci'' as valid. Heintzman, et al. (2017) argue that it is in not a member of the ''Equus'' genus.

References

{{DEFAULTSORT:Equus conversidens Pleistocene mammals of North America Taxa named by Richard Owen Fossil taxa described in 1869 Equus (genus)

Criticism

See also

References