''Toromeryx'' is a medium-sized extinct

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 ...

Artiodactyla Artiodactyls are placental mammals belonging to the order (biology), 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 ...

, of the family

Protoceratidae Protoceratidae is an extinct family of herbivorous North American artiodactyls (even-toed ungulates) that lived during the Eocene through Pliocene. While early members of the group were hornless, in later members males developed elaborate crani ...

, endemic to southwestern

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 ...

from the

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

epoch (Late

Uintan The Uintan North American Stage is the North American faunal stage, typically set from 46,200,000 to 42,000,000 years before present lasting 4.2 million years. The Uintan Stage is a key part of the North American land mammal age, North American Lan ...

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 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) ...

. However they were more closely related to

camel A camel (from and () from Ancient Semitic: ''gāmāl'') is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. Camels have long been domesticated and, as livestock, they provid ...

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 The rostral scale, or rostral, in snakes and other sca ...

horns above the

orbital cavity In anatomy, the orbit is the cavity or socket/hole 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 ...

. ''Toromeryx'' was smaller than Miocene members of Tylopoda: ''

Paratoceras ''Paratoceras'' is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America. They lived during the Early to Middle Miocene, 20.4—10.3 Ma, existing for approximately . ''Paratoceras'' resembled deer, but were pr ...

'', ''

Protoceras ''Protoceras'' ('first horn') is an extinct genus of Artiodactyla, of the family Protoceratidae, endemic to North America. It lived from the Oligocene to the Early Miocene 33.3—16.0 Ma, existing for approximately . Morphology ''Protocera ...

'', and '' Pseudoprotoceras''.

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 i ...

*Casa Blanca Site,

Laredo Formation The Laredo Formation is a geologic formation and LagerstätteGarten & Gee, in Reitner et al., 2013, p.57 in Texas, United States, and Nuevo León and Tamaulipas, Mexico. It preserves fossils dating back to the Lutetian stage of the Eocene period. ...

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, secre ...

References

Eocene Artiodactyla Protoceratids Eocene mammals of North America Fossil taxa described in 1974 Monotypic prehistoric Artiodactyla genera {{paleo-eventoedungulate-stub