''Amerhippus'' is an extinct
South American
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
horse of uncertain taxonomic identity. It is sometimes classified as a
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
of the genus ''
Equus'', containing several extinct species of horses that lived in South America, or a single, morphologically variable extinct species, ''Equus neogeus.''
Description
It lived from 2.588 to 0.012 Mya. It measured roughly tall and weighed approximately .
Distribution
They were one of two groups of equines in South America, alongside ''
Hippidion
''Hippidion'' (meaning ''little horse'') is an extinct genus of Equinae, equine that lived in South America from the Late Pliocene to the end of the Late Pleistocene (Lujanian), between two million and 11,000 years ago. They were one of two linea ...
''.
Fossils have been recovered from the
Tarija Formation
Tarija or San Bernardo de la Frontera de Tarixa is a city in southern Bolivia. Founded in 1574, Tarija is the largest city and capital and municipality within the Tarija Department, with an airport (Capitán Oriel Lea Plaza Airport, (TJA)) offe ...
of
Bolivia
, image_flag = Bandera de Bolivia (Estado).svg
, flag_alt = Horizontal tricolor (red, yellow, and green from top to bottom) with the coat of arms of Bolivia in the center
, flag_alt2 = 7 × 7 square p ...
, the
Serranía del Perijá
The Serranía del Perijá, Cordillera de Perijá or Sierra de Perijá is a mountain range, an extension of the eastern Andean branch ( Cordillera Oriental), in northern South America, between Colombia and Venezuela
Venezuela (; ), offici ...
in
Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
, the
Chiu-Chiu Formation of
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...
, the
Sabana Formation
The Sabana Formation ( es, Formación Sabana, Q1sa, QTs) is a geological formation of the Bogotá savanna, Altiplano Cundiboyacense, Eastern Ranges of the Colombian Andes. The formation consists mainly of shales with at the edges of the Bogotá ...
of the
Bogotá savanna
The Bogotá savanna is a montane savanna, located in the southwestern part of the Altiplano Cundiboyacense in the center of Colombia. The Bogotá savanna has an extent of and an average altitude of . The savanna is situated in the Eastern Range ...
in
Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
,
and from various locations in
Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...
.
Ecology
A 2019 study suggested that ''Equus neogeus'' was primarily a
grazer Grazer may refer to:
*grazer, an animal that grazes
*Grazer, a native or inhabitant of Graz
*GRAZER, the shoegaze band GRAZER
Astronomy
*Earth Grazer, Earth-grazing fireball that enters the Earth's atmosphere and leaves again
*Mercury grazer, ast ...
that fed on both
C4 and
C3 grasses in
prairies
Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...
and open woodlands.
Taxonomy
While they have formerly been referred to as belonging to 5 separate species, this has been revised down into three, and more recently a single, morphologically variable species ''Equus neogeus''. ''Equus'' first appeared in South America during the late
Early Pleistocene
The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...
around 1 Ma.
A 2008 study of
mitochondrial DNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...
fragments of a specimen of ''E. neogeus'' found it to be nested within mitochondrial lineages of ''
E. caballus,'' however, later studies suggested that this result required more specimens to be analysed for confirmation. A close relationship to caballine horses was also supported by a 2019 morphological analysis study.
Gallery
File:Caballo sudamericano (Parque chuyaca - Osorno).jpg, Statue in Osorno, Chile
File:South American Pleistocene equids.jpg, Restoration of hippidiforms with grazing ''Amerhippus'' in the background
File:Amerhippus A6 digital.jpg, Photo-reconstruction of ''Equus (Amerhippus) andium'' from paleoartist Roman Uchytel
References
{{Equus
Pleistocene horses
Pleistocene mammals of South America
Lujanian
Ensenadan
Uquian
Pleistocene Bolivia
Fossils of Bolivia
Pleistocene Chile
Fossils of Chile
Pleistocene Colombia
Fossils of Colombia
Pleistocene Ecuador
Fossils of Ecuador
Pleistocene Venezuela
Fossils of Venezuela
Fossil taxa described in 1950
Taxa named by Robert Hoffstetter
Animal subgenera
Equus (genus)