''Toromeryx'' is a medium-sized extinct

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 ...

Artiodactyla 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 ...

, of the family

Protoceratidae Protoceratidae is an extinct family of herbivorous North American artiodactyls (even-toed ungulates) that lived during the Eocene through Pliocene at around 46.2—4.9 Mya, existing for about 41 million years. Classification Protoceratidae was ...

, endemic to southwestern

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 ...

from the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

epoch (Late

Uintan The Uintan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 46,200,000 to 42,000,000 years BP lasting . It falls within the ...

stage) 46.2—42 Ma, existing for approximately .

Taxonomy

''Toromeryx'' was named by Wilson (1974). Its type is ''Toromeryx marginensis''. It was assigned to Protoceratidae by Wilson (1974), Carroll (1988), Prothero (1998) and Prothero and Ludtke (2007).D. R. Prothero and J. A. Ludtke. 2007. Family Protoceratidae. in D. R. Prothero and S. Foss (eds.), The Evolution of Artiodactyls 169-176

Morphology

''Toromeryx'' resembled

deer 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 ...

. However they were more closely related to

camel A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. C ...

ids. In addition to having horns in the more usual place, protoceratids had additional,

rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...

horns above the

orbital cavity In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents. In the adult human, the volume of the orbit is , of ...

. ''Toromeryx'' was smaller than Miocene members of Tylopoda: '' Paratoceras'', '' Protoceras'', and ''

Pseudoprotoceras ''Pseudoprotoceras'' is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to central North America. It lived during the Late Eocene 37.2—33.9 Annum, Ma, existing for approximately . ''Pseudoprotoceras'' resembled hornlessE ...

''.

Fossil distribution

Fossils have been recovered from: *Candelaria TMM 31281 Colmena Tuff Formation,

Presidio County, Texas Presidio County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 6,131. Its county seat is Marfa. The county was created in 1850 and later organized in 1875. Presidio County (K-5 in Texas topological ind ...

*Casa Blanca Site, Laredo Formation,

Webb County, Texas Webb County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 267,114. Its county seat is Laredo. The county was named after James Webb (1792–1856), who served as secretary of the treasury, secreta ...

References

Eocene even-toed ungulates Eocene mammals of North America Fossil taxa described in 1974 Prehistoric even-toed ungulate genera {{paleo-eventoedungulate-stub