''Camelops'' is an 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 ...

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 ...

that lived in

North North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography. Etymology T ...

and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

from the middle

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

(around 13-12,000 years ago). It is more closely related to living camels than to lamines (

llama The llama (; or ) (''Lama glama'') is a domesticated South American camelid, widely used as a List of meat animals, meat and pack animal by Inca empire, Andean cultures since the pre-Columbian era. Llamas are social animals and live with ...

alpaca The alpaca (''Lama pacos'') is a species of South American camelid mammal. Traditionally, alpacas were kept in herds that grazed on the level heights of the Andes of Southern Peru, Western Bolivia, Ecuador, and Northern Chile. More recentl ...

vicuña The vicuña (''Lama vicugna'') or vicuna (both , very rarely spelled ''vicugna'', Vicugna, its former genus name) is one of the two wild South American camelids, which live in the high alpine tundra, alpine areas of the Andes; the other cameli ...

s, and guanacos), making it a true camel of the Camelini

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 ...

. Its name is derived from the

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

(, "camel") and (, "face"), i.e. "camel-face". ''Camelops'' lived across western North America, ranging from the Pacific Coast to the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

, southwards to Honduras and northwards to Alaska. ''Camelops'' became extinct as part of the end-Pleistocene extinction event along with most large mammals across the Americas. The extinctions followed the arrival of humans to the Americas, and evidence has been found indicating that humans butchered ''Camelops,'' suggesting that hunting may have been a factor in its extinction.

Taxonomy and evolution

History of research

''Camelops'' was first named by Joseph Leidy in 1854, based on a partial

maxilla In vertebrates, the maxilla (: maxillae ) is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The two maxil ...

(upper jaw bone), that was found in a gravel drift somewhere in the

Kansas Territory The Territory of Kansas was an organized incorporated territory of the United States that existed from May 30, 1854, until January 29, 1861, when the eastern portion of the territory was admitted to the United States, Union as the Slave and ...

, with Leidy naming the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

''Camelops kansanus'' in the same publication based on the maxilla. Later authors have judged that while the jawbone undoubtedly represents ''Camelops'', it is too fragmentary to be diagnostic to species, making ''C. kansanus'' a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

''. Later in 1874, Leidy named the species ''Camelops hesternus'', based on teeth found in a gravel deposit in Arroyo Las Positas in Livermore Valley, Alameda County in the southern Bay Area of California. Several other species, including ''Camelops sulcatus'' named by

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontology, paleontologist, comparative anatomy, comparative anatomist, herpetology, herpetologist, and ichthyology, ichthyologist. Born to a wealthy Quaker fam ...

in 1893 based on a partial left mandible, found at Rock Creek, Texas, as well as ''Camelops huerfanensis'', named by Francis Whittemore Cragin in 1892 based on remains found along the Huerfano River in Colorado (as well as its claimed subspecies ''Camelops huerfanensis dallasi'' named by Richard Swann Lull in 1921 for remains collected along the Trinity River in northeast Texas), ''Camelops aransas'' named by

Oliver Perry Hay Oliver Perry Hay (May 22, 1846 – November 2, 1930) was an American herpetologist, ichthyologist, and paleontologist. Hay was born in Jefferson County, Indiana, to Robert and Margaret Hay. In 1870, Hay graduated with a bachelor of arts from ...

in 1926 for remains including a partial right mandible found on a bank of the Aransas River in southeast Texas, and ''Camelop''s ''traviswhitei'' named by Mooser and Dalquist in 1975 from remains found in

Aguascalientes Aguascalientes, officially the Free and Sovereign State of Aguascalientes, is one of the 32 states which comprise the Political divisions of Mexico, Federal Entities of Mexico. At 22°N and with an average altitude of above sea level it is pre ...

in central Mexico, are now regarded as junior synonyms of ''C. hesternus''. Another species, ''C. minidokiae'', named by Hay in 1927 for jaw and teeth remains found in a gravel bed near Minidoka, Idaho, has been suggested to also be potentially valid, given its apparently smaller size than ''C. hesternus,'' though other authors have suggested that it is another synonym for ''C. hesternus''. This species is primarily recorded during the Irvingtonian (Early-Middle Pleistocene), though some remains of the species have been reported from the Rancholabrean (late Middle-Late Pleistocene). Some scientific publications have used the informal names "Western Camel" and "Yesterday's Camel" for ''Camelops''.

Evolution

The family Camelidae, which contains the living

s as well as lamines (the tribe Lamini, which includes the

, guanaco,

and

), first emerged in North America during 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 ...

, around 46-42 million years ago, reaching its apex of diversity 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 ...

epoch (23-5.3 million years ago). The two modern tribes of Camelidae, Camelini and Lamini, are suggested to have diverged during this period, around 17.5-16 million years ago. Living camels are thought to descend from '' Paracamelus,'' which crossed the

Bering Land Bridge Beringia is defined today as the land and maritime area bounded on the west by the Lena River in Russia; on the east by the Mackenzie River in Canada; on the north by 72° north latitude in the Chukchi Sea; and on the south by the tip of the ...

into Eurasia from North America during the Late Miocene, around 6 million years ago. Although historically often assigned to Lamini,

ancient DNA Ancient DNA (aDNA) is DNA isolated from ancient sources (typically Biological specimen, specimens, but also environmental DNA). Due to degradation processes (including Crosslinking of DNA, cross-linking, deamination and DNA fragmentation, fragme ...

obtained from ''Camelops'' indicates that it is a member of Camelini more closely related to living camels than to lamines, making it a true camel, with an estimated divergence from living camels around 11-10 million years ago. Phylogenetic relationships of ''Camelops'' compared to living and recently extinct camels, after Yuan et al. (2024).The oldest fossils of ''Camelops'' are known from southern North America, dating to around 4-3.2 million years ago during the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 During the Pliocene and Early Pleistocene epochs (

Blancan The Blancan 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 4,750,000 to 1,806,000 years BP, a period of .Irvingtonian) other camels, such as '' Gigantocamelus'', '' Blancocamelus'', '' Titanotylopus'' and '' cf. Paracamelus'' were also present in North America,Harrison, J. A
Giant camels from the Cenzoic of North America
''Smithsonian Contribution to Paleobiology'' 57, 1–29 (1985) . but by the Late Pleistocene (Rancholabrean), ''Camelops'' represented the last remaining camel in the Americas.

Description

''Camelops hesternus'' was a large camel with a bodyform similar to a living

dromedary The dromedary (''Camelus dromedarius''), also known as the dromedary camel, Arabian camel and one-humped camel, is a large camel of the genus '' Camelus'' with one hump on its back. It is the tallest of the three camel species; adult males sta ...

, reaching a shoulder height of Anthony J. Stuart, 2021, ''Vanished Giants: The Lost World of the Ice Age'', "6.17 Yesterday's Camel: Camelops Hesternus", p.99,

University of Chicago Press The University of Chicago Press is the university press of the University of Chicago, a Private university, private research university in Chicago, Illinois. It is the largest and one of the oldest university presses in the United States. It pu ...

with body mass estimates ranging from to , to around , though the size of the species was variable, with individuals known from the far north of the species range in Alaska and Yukon being considerably smaller than those from elsewhere. Whether ''Camelops'' had humps or not like living camels is uncertain. The skull has 1 incisor, 1 canine, 2

premolar The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

s and 3

molars The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...

in each half of the upper jaw, and 3 incisors, 1 canine, 1 premolar and 3 molars in each half of the lower jaw. The upper first premolar and both upper and lower second premolars are absent, with the lower first premolar usually absent and only occasionally present. The molar and premolar teeth are very high-crowned ( hypsodont), with the molars being slender relative to their length, with the canines, upper third premolar and lower fourth premolar being reduced in size. The

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammals h ...

bone is robust, with the rostrum of the skull being elongate, with the facial region of the skull not exhibiting considerable shortening. The nasal bones are strongly arched. The brain is relatively large, estimated at . The mandible is relatively deep. The limbs are relatively elongate (around 20% longer than those of living dromedaries) but robust. The metapodial bones are robust and relatively short.

Distribution, habitat and ecology

During the Pleistocene'', Camelops'' is known from fossils across western North America, ranging from California, Oregon and Washington State, eastwards to South Dakota, Nebraska, Kansas, Oklahoma and Texas, with rarer records further east, including near the Missouri-Illinois border. Southwards ''Camelops'' ranged to Honduras in Central America. The northernmost records of ''Camelops'' are known from Alaska and Yukon, but it probably only occupied this region during warm

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene i ...

intervals, before becoming extirpated from the region during glacial periods, as is thought for some other species whose remains are also rarely found in the region, such as the ground sloth '' Megalonyx jeffersoni,''

mastodon A mastodon, from Ancient Greek μαστός (''mastós''), meaning "breast", and ὀδούς (''odoús'') "tooth", is a member of the genus ''Mammut'' (German for 'mammoth'), which was endemic to North America and lived from the late Miocene to ...

s and '' Castoroides'' giant beavers. Across its range it inhabited a wide variety of habitats, from subtropical environments, to tundra, though it seems to have primarily lived in open habitats. In parts of its range ''Camelops hesternus'' co-occurred alongside the lamines '' Hemiauchenia'' and '' Palaeolama''. An isotopic analysis study from 2016 including specimens across the species range concluded that ''Camelops hesternus'' was a browser that consumed shrubbery, including species with a both a C₃ and C₄ type carbon fixation, as well as possibly those with Crassulacean acid metabolism. Plants consumed by ''Camelops'' are suggested to include

saltbrush ''Atriplex'' () is a plant genus of about 250 species, known by the common names of saltbush and orache (; also spelled orach). It belongs to the subfamily Chenopodioideae of the family (biology), family Amaranthaceae sensu, ''s.l.''. The genus ...

(''Atriplex''), a plant also commonly found in the diet of living camels. Other studies have supported a browsing or mixed feeding diet for ''Camelops'', but a 2021 dental wear analysis study suggested that in some locations such as in Nebraska, ''Camelops hesternus'' engaged in

grazing In agriculture, grazing is a method of animal husbandry whereby domestic livestock are allowed outdoors to free range (roam around) and consume wild vegetations in order to feed conversion ratio, convert the otherwise indigestible (by human diges ...

, sometimes predominantly so, suggesting that ''Camelops hesternus'' was a flexible feeder. Tracks found in Alberta, Canada suggest that like living camels, ''Camelops'' probably lived in herds, which like living camels may have been led by a dominant adult male. Isotopic analysis suggests that ''Camelops'' may have engaged in seasonal migrations. As in living camels, ''Camelops'' may have had a slow reproductive rate, including giving birth to a single offspring at a time, as well as existing at relatively low population densities due to its large size. ''Camelops hesternus'' was probably predated upon by large carnivores, which during the Late Pleistocene may have included dire wolves (''Aenocyon dirus'') the sabertooth cat ''

Smilodon fatalis ''Smilodon'' is an extinct genus of felids. It is one of the best known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats, belon ...

,'' the scimitar-toothed cat (''Homotherium serum'') and the American lion (''Panthera atrox''). Specimens of ''Camelops'' have been found exhibiting signs of disease like

osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

Relationship with humans and extinction

''Camelops'' went extinct around 13-12,000 years ago as part of the end-Pleistocene extinction event along with most other large mammals across the Americas. These extinctions followed the arrival of humans to the Americas, and it is suggested that human hunting may have had a contributory role in the extinctions (though some authors have argued that climatic change was the most important factor). At Wally's Beach in Alberta, Canada, butchered remains of ''Camelops hesternus'' displaying cut and fracture marks, alongside those of caballine true horses are associated with stone tools, with the site radiocarbon dated to around 13,300 years ago. This represents the only confirmed ''Camelops'' butchery site. The site was originally attributed to the Clovis culture based on the similar timing as well as findings of unassociated Clovis points within the local area, but the site does not display clear evidence of Clovis-type tools. Some authors have suggested that fractured bones of ''Camelops'' found near

Casper, Wyoming Casper is a city in and the county seat of Natrona County, Wyoming, United States. Casper is the List of municipalities in Wyoming, second-most populous city in the state after Cheyenne, Wyoming, Cheyenne, with the population at 59,038 as of th ...

(which also represent the youngest well-dated remains of the species, dating to around 13,060 years Before Present) may represent a butchery site, but this is not definitive. Other possible, but not definitive sites where ''Camelops'' remains may be associated with human activity include Carter/Kerr-McGee and Colby sites in Wyoming (the latter of which is associated with a Clovis point) and the Lehner site in Arizona. A sacrum of ''Camelops'' found near Tequixquiac in central Mexico has been suggested to have been shaped to resemble an animal head.

References

{{Taxonbar, from=Q133439 Prehistoric camelids Prehistoric Artiodactyla genera Pliocene Artiodactyla Pleistocene Artiodactyla Piacenzian first appearances Holocene extinctions Pliocene mammals of North America Pleistocene mammals of North America Taxa named by Joseph Leidy Fossil taxa described in 1854