''Equus conversidens'', or the Mexican horse, is a dubious
Pleistocene
The Pleistocene ( , often referred to as the '' Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed ...
species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
of
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 million ...
, now extinct, that inhabited
North America.
The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...
of ''Equus conversidens'', a partial palate, was unearthed in Pleistocene deposits northeast of Mexico City,
Mexico
Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...
. 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 census. It is part of the Amarillo, Texas, metropolitan statistical area. Canyon is the home of West Texas A&M University a ...
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 (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
(including a skeleton from Slaton),
Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a U.S. state, state in the Southwestern United States. It is the list of U.