The Antilocapridae are a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

of ruminant

artiodactyls Artiodactyls are placental mammals belonging to the order Artiodactyla ( , ). Typically, they are ungulates which bear weight equally on two (an even number) of their five toes (the third and fourth, often in the form of a hoof). The other thre ...

endemic to

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 ...

. Their closest

extant Extant or Least-concern species, least concern is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Exta ...

relatives are the giraffids. 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 ante ...

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

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

. The living pronghorn is a small

ruminant Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microb ...

mammal resembling an

antelope The term antelope refers to numerous extant or recently extinct species of the ruminant artiodactyl family Bovidae that are indigenous to most of Africa, India, the Middle East, Central Asia, and a small area of Eastern Europe. Antelopes do ...

Description

In most respects, antilocaprids resemble other

ruminants Ruminants are herbivorous grazing or browsing artiodactyls belonging to the suborder Ruminantia that are able to acquire nutrients from plant-based food by Enteric fermentation, fermenting it in a specialized stomach prior to digestion, principa ...

. They have a complex, four-chambered stomach for digesting tough plant matter, cloven hooves, and small, forked horns. Their horns resemble those of the

bovid The Bovidae comprise the family (biology), biological family of cloven-hoofed, ruminant mammals that includes Bos, cattle, bison, Bubalina, buffalo, antelopes (including Caprinae, goat-antelopes), Ovis, sheep and Capra (genus), goats. A member o ...

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 bones 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-physiology ...

as most other ruminants: .

Classification

The antilocaprids are

s of the clade

Pecora Pecora is an Order (biology), infraorder of Artiodactyla, 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 ...

. Other extant pecorans are the families

Giraffidae The Giraffidae are a family (biology), family of ruminant artiodactyl mammals that share a recent common ancestor with deer and bovids. This family, once a diverse group spread throughout Eurasia and Africa, presently comprises only two extant ge ...

(

giraffe The giraffe is a large Fauna of Africa, African even-toed ungulate, hoofed mammal belonging to the genus ''Giraffa.'' It is the Largest mammals#Even-toed Ungulates (Artiodactyla), tallest living terrestrial animal and the largest ruminant on ...

s),

Cervidae A deer (: deer) or true deer is a hoofed ruminant ungulate of the family Cervidae (informally the deer family). Cervidae is divided into subfamilies Cervinae (which includes, among others, muntjac, elk (wapiti), red deer, and fallow deer) a ...

(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 eight, of the species that make up ''Moschus'', the only extant genus of the family (biology), family Moschidae. Despite being commonly called deer, they are not true deer belonging to the family Cervidae, b ...

), and

Bovidae The Bovidae comprise the family (biology), biological family of cloven-hoofed, ruminant mammals that includes Bos, cattle, bison, Bubalina, buffalo, antelopes (including Caprinae, goat-antelopes), Ovis, sheep and Capra (genus), goats. A member o ...

(

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

, 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 large-scale ruminant genome sequencing study in 2019 suggested that 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 ...

to Giraffidae, as shown in the

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

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 (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

. 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 immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

woodland A woodland () is, in the broad sense, land covered with woody plants (trees and shrubs), 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 sunli ...

s into open

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

grassland A grassland is an area where the vegetation is dominance (ecology), dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes such as clover, and other Herbaceo ...

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 epoch (geology), 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 mea ...

and

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Osbornoceros'', 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). Taxon ...

'', with fan-shaped horns, and '' Hayoceros'', 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 botanical subfamily names with "-oideae", and zo ...

Antilocaprinae **

Tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

Antilocaprini ***

Genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 survived ...

'' ****'' Antilocapra americana'' -

*****''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, Endemism, endemic to Baja California peninsula, Baja California in Mexico. The wild population is estimated at 200. Popu ...

*****''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 ...

*****''A. a. oregona'' - Oregon pronghorn ****†'' Antilocapra pacifica'' ***Genus †'' Texoceros'' ****''Texoceros altidens'' ****''Texoceros edensis'' ****''Texoceros guymonensis'' ****''Texoceros minorei'' ****''Texoceros texanus'' ****''Texoceros vaughani'' **Tribe †Ilingoceratini ***Genus †'' Ilingoceros'' ****''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 osborni'' **Tribe Stockoceratini ***Genus †''

Capromeryx ''Capromeryx'' (dwarf pronghorn) is an extinct 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 th ...

'' - (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'' ****''Hayoceros barbouri'' ****''Hayoceros falkenbachi'' ***Genus †'' Hexameryx'' ****''Hexameryx simpsoni'' ***Genus †'' Hexobelomeryx'' ****''Hexobelomeryx fricki'' ****''Hexobelomeryx simpsoni'' ***Genus †''

Stockoceros ''Stockoceros'' is an extinct genus of the North American artiodactyl family Antilocapridae (pronghorns), known from what is now Mexico and the southwestern United States. The genus survived until about 12,000 years ago, and was present when Pale ...

'' ****''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 in Canada. Taxonomy The name means "four ornedruminant", referring to the division of e ...

'' ****''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 ungulate Ungulates ( ) are members of the di ...

**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 New Mexico is a state in the Southwestern United States, Southwestern region of the ...

'' (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 antilocaprids that lived in North America during the Miocene. Taxonomy It was originally described as a subgenus of ''Cosoryx'', but was elevated to full genus status. It has been suggest that ''Paracosory ...

'' ***''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

{{Authority control Mammal families Extant Miocene first appearances Taxa named by John Edward Gray *