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. Their closest extant relatives are the giraffids with which they comprise the superfamily Giraffoidea. 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. The living pronghorn is a small

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

mammal resembling an antelope.

Description

In most respects, antilocaprids resemble other ruminants. 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 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-physiolog ...

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 “Pec ...

. 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 ...

( giraffes),

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 reind ...

(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), 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, t ...

(

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 ma ...

, goats and sheep, wildebeests and allies, and antelopes). 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 ...

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 ...

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

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 (se ...

s into open savannah

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 na ...

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 in the geologic time scale that extends from 5.333 million to 2.58Osbornoceros'', with smooth, slightly curved horns, ''Paracosoryx'', with flattened horns that widened to forked tips, '' Ramoceros'', with fan-shaped horns, and '' Hayoceros'', with four horns.

Species

* Subfamily 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 is in the discipline of anthropology. This definition is contested, in part due to confli ...

Antilocaprini ***

Genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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

*****''A. a. americana'' - Common pronghorn *****''A. a. mexicana'' - Mexican pronghorn *****''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 *****''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 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 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'' - (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 conklingi'' (junior synonym ''S. onusrosagris'') Antilocaprid

***Genus †'' Tetrameryx'' ****''Tetrameryx irvingtonensis'' ****''Tetrameryx knoxensis'' ****''Tetrameryx mooseri'' ****''Tetrameryx shuleri'' ****''Tetrameryx tacubayensis'' *Subfamily † Merycodontinae **Genus †'' Cosoryx'' ***''Cosoryx cerroensis'' ***''Cosoryx furcatus'' ***''Cosoryx ilfonensis'' **Genus †'' Merriamoceros'' ***''Merriamoceros coronatus'' **Genus †'' Merycodus'' (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 alticornis'' ***''Paracosoryx burgensis'' ***''Paracosoryx dawesensis'' ***''Paracosoryx furlongi'' ***''Paracosoryx loxoceros'' ***''Paracosoryx nevadensis'' ***''Paracosoryx wilsoni'' **Genus †'' Ramoceros'' ***''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 *