The Antilocapridae are a family of

artiodactyls The even-toed ungulates (Artiodactyla , ) are ungulates—hoofed animals—which bear weight equally on two (an even number) of their five toes: the third and fourth. The other three toes are either present, absent, vestigial, or pointing poster ...

endemic to

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. Their closest extant relatives are the giraffids with which they comprise the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Giraffoidea Giraffoidea is a superfamily that includes the families Climacoceratidae, Antilocapridae, and Giraffidae. The only extant members in the superfamily are the pronghorn, giraffe, and okapi. The Climacoceratidae are also placed in the superfamil ...

. Only one species, the

pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

(''Antilocapra americana''), is living today; all other members of the family are

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

. The living pronghorn is a small

ruminant Ruminants (suborder Ruminantia) are ungulate, hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach prior to digestion, principally ...

mammal resembling an

antelope The term antelope is used to refer to many species of even-toed ruminant that are indigenous to various regions in Africa and Eurasia. Antelope comprise a wastebasket taxon defined as any of numerous Old World grazing and browsing hoofed mammals ...

Description

In most respects, antilocaprids resemble other ruminants. They have a complex, four-chambered stomach for digesting tough plant matter,

cloven hooves A cloven hoof, cleft hoof, divided hoof or split hoof is a hoof split into two toes. This is found on members of the mammalian order Artiodactyla. Examples of mammals that possess this type of hoof are cattle, deer, pigs, antelopes, gazelles, ...

, and small, forked horns. Their horns resemble those of the

bovid The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...

s, in that they have a true horny sheath, but, uniquely, they are shed outside the breeding season, and subsequently regrown. Their lateral toes are even further diminished than in bovids, with the digits themselves being entirely lost, and only the

cannon bone Good conformation in the limbs leads to improved movement and decreased likelihood of injuries. Large differences in bone structure and size can be found in horses used for different activities, but correct conformation remains relatively simil ...

s remaining. Antilocaprids have the same

dental formula Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolo ...

as most other ruminants: .

Classification

The antilocaprids are

s of the clade

Pecora Pecora is an infraorder of even-toed hoofed mammals with ruminant digestion. Most members of Pecora have cranial appendages projecting from their frontal bones; only two extant genera lack them, ''Hydropotes'' and ''Moschus''. The name “Pecor ...

. Other extant pecorans are the families

Giraffidae The Giraffidae are a family of ruminant artiodactyl mammals that share a common ancestor with deer and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant genera, the giraffe (one or ...

(

giraffe The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, ''Giraffa camelopardalis ...

s),

Cervidae Deer or true deer are hoofed ruminant mammals forming the family Cervidae. The two main groups of deer are the Cervinae, including the muntjac, the elk (wapiti), the red deer, and the fallow deer; and the Capreolinae, including the reindeer ...

(deer),

Moschidae Moschidae is a family of pecoran even-toed ungulates, containing the musk deer (''Moschus'') and its extinct relatives. They are characterized by long 'saber teeth' instead of horns, antlers or ossicones, modest size (''Moschus'' only reaches ; ...

(

musk deer Musk deer can refer to any one, or all seven, of the species that make up ''Moschus'', the only extant genus of the family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, but rather their fa ...

), and

Bovidae The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...

(

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

, goats and sheep, wildebeests and allies, and

s). The exact interrelationships among the pecorans have been debated, mainly focusing on the placement of Giraffidae, but a recent large-scale ruminant genome sequencing study suggests Antilocapridae are the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

to Giraffidae, as shown in the

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...

below.

Evolution

The ancestors of pronghorn diverged from the giraffids in the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was prece ...

. This was in part of a relatively late mammal diversification following a climate change that transformed

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

s into open

savannah A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient light to rea ...

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s. The antilocaprids evolved in North America, where they filled a niche similar to that of the bovids that evolved in the Old World. During the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Osbornoceros ''Osbornoceros'' is an extinct artiodactyl genus of the family Antilocapridae.Frick 1937 All antilocaprid species are extinct except for the pronghorn. ''Osbornoceros osborni'' is the only known species of the genus ''Osbornoceros''. ''Osbornoc ...

'', with smooth, slightly curved horns, ''Paracosoryx'', with flattened horns that widened to forked tips, ''

Ramoceros ''Ramoceros'' is an extinct genus of the artiodactyl family Antilocapridae endemic to Middle Miocene (Clarendonian) North America.Blount, Kitty and Crowley, Maggie. ''Encyclopedia of Dinosaurs & Prehistoric Life'', p. 271 (Penguin, 2008). Tax ...

'', with fan-shaped horns, and ''

Hayoceros ''Hayoceros'' is an extinct genus of the artiodactyl family Antilocapridae, endemic to North America during the Pleistocene epoch (1.8 mya—300,000 years ago), existing for about 1.5 million years. Taxonomy ''Hayoceros'' was named by Skinner ...

'', with four horns.

Species

Subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Antilocaprinae **

Tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...

Antilocaprini ***

Genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Antilocapra ''Antilocapra'' is a genus of the family Antilocapridae, which contains only a single living species, the pronghorn ''(Antilocapra americana)''. Another species, the Pacific pronghorn, lived in California during the Late Pleistocene and survive ...

'' ****''

Antilocapra americana The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

'' -

*****''A. a. americana'' - Common pronghorn *****''A. a. mexicana'' -

Mexican pronghorn The Mexican pronghorn (''Antilocapra americana mexicana'') is a pronghorn native to Mexico. It was found in the United States (in Arizona), but is considered extirpated there. Reintroduction With the Mexican pronghorn being an endangered species ...

*****''A. a. peninsularis'' -

Baja California pronghorn The Baja California pronghorn or peninsular pronghorn (''Antilocapra americana peninsularis'') is a subspecies of pronghorn, endemic to Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja ...

*****''A. a. sonoriensis'' -

Sonoran pronghorn The Sonoran pronghorn (''Antilocapra americana sonoriensis'') is an endangered subspecies of pronghorn that is endemic to the Sonoran Desert. Conservation Around 200 animals currently are believed to exist in Arizona in the United States, up fr ...

*****''A. a. oregona'' -

Oregon pronghorn Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...

****†'' Antilocapra pacifica'' ***Genus †'' Texoceros'' ****''Texoceros altidens'' ****''Texoceros edensis'' ****''Texoceros guymonensis'' ****''Texoceros minorei'' ****''Texoceros texanus'' ****''Texoceros vaughani'' **Tribe † Ilingoceratini ***Genus †''

Ilingoceros ''Ilingoceros'' is an extinct genus of pronghorn artiodactyl from the Late Miocene of North America. At in body length, the animal would have been slightly bigger than the related modern pronghorn. It had straight, spiraled horns, which ende ...

'' ****''Ilingoceros alexandrae'' ****''Ilingoceros schizoceros'' ***Genus †'' Ottoceros'' ****''Ottoceros peacevalleyensis'' ***Genus †'' Plioceros'' ****''Plioceros blicki'' ****''Plioceros dehlini'' ****''Plioceros floblairi'' ***Genus †'' Sphenophalos'' ****''Sphenophalos garciae'' ****''Sphenophalos middleswarti'' ****''Sphenophalos nevadanus'' **Tribe † Proantilocaprini ***Genus †'' Proantilocapra'' ****''Proantilocapra platycornea'' ***Genus †''

Osbornoceros ''Osbornoceros'' is an extinct artiodactyl genus of the family Antilocapridae.Frick 1937 All antilocaprid species are extinct except for the pronghorn. ''Osbornoceros osborni'' is the only known species of the genus ''Osbornoceros''. ''Osbornoc ...

'' ****''Osbornoceros osborni'' **Tribe

Stockoceratini The Antilocapridae are a family of artiodactyls endemic to North America. Their closest extant relatives are the giraffids with which they comprise the superfamily Giraffoidea. Only one species, the pronghorn (''Antilocapra americana''), is li ...

***Genus †''

Capromeryx ''Capromeryx'' (dwarf pronghorn) was a genus of dwarf pronghorns ( Antilocapridae) that originated in North America during the Pliocene about 5 million years ago (the exact range of their presence on the landscape is still not known, but the most r ...

'' - (junior synonym ''Breameryx'') ****''Capromeryx arizonensis'' - (junior synonym ''B. arizonensis'') ****''Capromeryx furcifer'' - (junior synonyms ''B. minimus'', ''C. minimus) ****''Capromeryx gidleyi'' - (junior synonym ''B. gidleyi'') ****''Capromeryx mexicana'' - (junior synonym ''B. mexicana'') ****''Capromeryx minor'' - (junior synonym ''B. minor'') ****''Capromeryx tauntonensis'' ***Genus †'' Ceratomeryx'' ****''Ceratomeryx prenticei'' ***Genus †''

'' ****''Hayoceros barbouri'' ****''Hayoceros falkenbachi'' ***Genus †''

Hexameryx ''Hexameryx'' is an extinct monospecific genus of the artiodactyl family Antilocapridae endemic to North America. It lived during the Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.3 ...

'' ****''Hexameryx simpsoni'' ***Genus †'' Hexobelomeryx'' ****''Hexobelomeryx fricki'' ****''Hexobelomeryx simpsoni'' ***Genus †'' Stockoceros'' ****''Stockoceros conklingi'' (junior synonym ''S. onusrosagris'')

***Genus †''

Tetrameryx ''Tetrameryx'' is an extinct genus of the North American artiodactyl family Antilocapridae, known from Mexico, the western United States, and Saskatchewan Saskatchewan ( ; ) is a province in western Canada, bordered on the west by Alberta, ...

'' ****''Tetrameryx irvingtonensis'' ****''Tetrameryx knoxensis'' ****''Tetrameryx mooseri'' ****''Tetrameryx shuleri'' ****''Tetrameryx tacubayensis'' *Subfamily †

Merycodontinae Merycondontinae is a subfamily of pronghorn that arose during the middle of the Miocene and became extinct by the end of that period. The Merycondontinae were small, slightly built, fast-running ungulates. Both males and females were horned. ...

**Genus †''

Cosoryx ''Cosoryx'' is an extinct genus of antilocaprid that lived in the Miocene of Nevada. Fossils of this genus have also been found in the Santa Fe Group in New Mexico. ''Cosoryx'' has sometimes been considered synonymous with ''Merycodus ' ...

'' ***''Cosoryx cerroensis'' ***''Cosoryx furcatus'' ***''Cosoryx ilfonensis'' **Genus †''

Merriamoceros ''Merriamoceros'' is an extinct genus of pronghorn. It is known from a single species, which is also the type species, ''M. coronatus''. Discovery and naming The type specimen (UCMP 20052) that defines this species is named ''Merriamoceros cor ...

'' ***''Merriamoceros coronatus'' **Genus †''

Merycodus ''Merycodus'' is an extinct genus of the artiodactyl family Antilocapridae. Fossils of this genus have been found in the Santa Fe Group of New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , s ...

'' (syn. ''Meryceros'' and ''Submeryceros'') ***''Merycodus crucensis'' ***''Merycodus hookwayi'' ***''Merycodus joraki'' ***''Merycodus major'' ***''Merycodus minimus'' ***''Merycodus minor'' ***''Merycodus necatus'' ***''Merycodus nenzelensis'' ***''Merycodus prodromus'' ***''Merycodus sabulonis'' ***''Merycodus warreni'' **Genus †''

Paracosoryx ''Paracosoryx'' is an extinct genus of antilocaprid that lived in North America during the Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Sco ...

'' ***''Paracosoryx alticornis'' ***''Paracosoryx burgensis'' ***''Paracosoryx dawesensis'' ***''Paracosoryx furlongi'' ***''Paracosoryx loxoceros'' ***''Paracosoryx nevadensis'' ***''Paracosoryx wilsoni'' **Genus †''

'' ***''Ramoceros brevicornis'' ***''Ramoceros marthae'' ***''Ramoceros merriami'' ***''Ramoceros osborni'' ***''Ramoceros palmatus'' ***''Ramoceros ramosus''

References

{{Taxonbar, from=Q3581369 Mammal families Extant Miocene first appearances Taxa named by John Edward Gray *