| Cuvieronius | |
|---|---|
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| Skull ofCuvieronius hyodon Muséum National d'Histoire Naturelle,Paris | |
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| Life restoration ofCuvieronius hyodon | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Proboscidea |
| Family: | †Gomphotheriidae |
| Genus: | †Cuvieronius Osborn, 1923 |
| Species: | †C. hyodon |
| Binomial name | |
| †Cuvieronius hyodon (Fischer, 1814) (conserved name) | |
| Synonyms | |
C. hyodon
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Cuvieronius is an extinctNew World genus ofgomphothere which ranged from southern North America to northwestern South America during thePleistocene epoch. Reaching a shoulder height of 2.3 metres (7.5 ft) and a body mass of 3.5 tonnes (7,700 lb), it was on average shorter but comparable in body mass to anAsian elephant.Cuvieronius inhabitedsubtropical andtropical latitudes in environments ranging fromgrasslands totropical rainforest. Among the last gomphotheres along with the South AmericanNotiomastodon, it became extinct as part of theend Pleistocene-extinction event, approximately 12,000 years ago, along with most other large mammals in the Americas. The extinctions followed thearrival of humans to the Americas, and evidence has been found for human hunting ofCuvieronius, which may have been a factor in its extinction.
The species now known asCuvieronius hyodon was among the firstfossil animals from the New World to be studied. The first remains of this species were recovered from Ecuador byAlexander von Humboldt, at a location the local population referred to as the "Field of Giants".[1] Humboldt recognized that, rather than being bones of giant humans as had been thought by the local population and previous Spanish colonists, they were similar to the giant elephants (Mastodon) being described fromOhio. Humboldt sent teeth that he had collected from Mexico, Ecuador, and Chile to French anatomistGeorges Cuvier, who classified the teeth into two species, which he referred to as the "mastodonte des cordilières" and the "mastodonte humboldtien", in an 1806 paper.[2] It was not until 1824 that Cuvier formally named the species. He referred both to the genusMastodon, calling themM. andium andM. humboldtii.[2]
Unknown to Cuvier, Fischer had, in 1814, already named the two species based on Cuvier's original description, in the new genusMastotherium asM. hyodon andM. humboldtii. The idea of two distinct species continued to be accepted into the 20th century, usually using Cuvier's names, though Fischer's names were older.[2] In 1923,Henry Fairfield Osborn recognized that these species were distinct fromMastodon, and assigned each to its own new genus,Cuvieronius humboldtii andCordillerion andium, with the nameCuvieronius in honour of Cuvier. However, by the 1930s, general agreement had shifted to regard both forms as representing a single, geographically widespread species, withCuvieronius humboldtii considered to be the correct name.[2] During the 1950s, the nomenclature of this species became increasingly tangled, as various scientists regarded thetype species of the genusCuvieronius to be Fischer's first published nameMastotherium hyodon, rather than the originally designatedMastodon humboldtii. This situation went unaddressed until 2009, when Spencer Lucas petitioned theInternational Commission on Zoological Nomenclature to officially change the type species ofCuvieronius toM. hyodon as had been followed for over 50 years by that time, rather than abandoning the well-knownCuvieronius as a synonym, as well as to designate the specimenMNHN TAR 1270, a skull and lower jaw fromTarija, Bolivia, as theneotype specimen of the genus/species.[2] In 2011, Opinion 2276 of the ICZN ruled to conserve the names.
The species level taxonomy ofCuvieronius is confused. Historically, several species were recognised, typicallyC. tropicus andC. hyodon for North and South American remains, respectively, but recent scholarship suggests that there is only a single valid pan-American species,C. hyodon.[3][4]
Alive, specimens typically stood about 2.3 m (7 ft 7 in) tall at the shoulder, and weighed about 3.5 tonnes (7,700 lb), making it around the same shoulder height as anAfrican forest elephant, but heavier and more comparable in weight to anAsian elephant.[5] The skull was relatively long and low-vaulted. The upper tusks were straight to slightly curved, and had a spiral shaped-enamel band,[3][6] and reached considerable size, with tusks in the region of 2.2 metres (7.2 ft) in length and weights in excess of 50 kilograms (110 lb).[7] The lower tusks present in more primitive gomphotheres werevestigial inCuvieronius, being only present in young juveniles, and the lower jaw shortened (brevirostrine).[8] The third molars typically had 4 to 4.5 lophs/lophids, with some specimens having 5 lophs/lophids, with relatively simple crowns.[6] The limb bones are very robust, even compared to other gomphotheres, likely corresponding with its relatively low body mass.[9]
Cuvieronius inhabitedtropical andsubtropical latitudes, in environments spanning fromsavanna andgrassland in northern Mexico,[10] opengallery forest in Guatemala,[11]tropical rainforest in Costa Rica,[12] and the arid cool-temperateAndes mountains in northwest South America.[13] It spanned altitudes from 90 metres (300 ft) below current sea level on thecontinental shelf (but which during the Pleistocene was periodically exposed as dry land) near thePearl Islands of what is now Panama,[4] to at least 3,880 metres (12,730 ft) above current sea level in the Bolivian Andes.[14]
Cuvieronius is suggested to have been a generalist mixed feeder that consumed a wide range of plant resources, including grasses andbrowse (the leaves and twigs of plants like trees and shrubs).[15] Costa RicanC. hyodon were specialised forest inhabitants that primarily fed onC3 plants.[12] In 1982,Daniel H. Janzen andPaul Schultz Martin suggested that the diet ofCuvieronius probably included fruit, and that it was likely an important seed disperser of a variety ofNeotropical plants with large fleshy fruits similar to those consumed by large animals in Africa, but which lack effective living native seed dispersers, which they described as "Pleistocene anachronisms".[16]Cuvierionius may have lived in herds, similar to modern elephants.[17]
Cuvieronius frequently co-occurred alongside othermegafauna species, such as the similarly sized elephantine giant ground slothEremotherium, the car-sized glyptodontGlyptotherium, and the rhinoceros-like ungulateMixotoxodon.[11]
Cuvieronius initially evolved in North America.[18][6] It is considered closely related to, if not derived from,Rhynchotherium, a North American gomphothere genus known from the Late Miocene and Pliocene.[3] Some authors have suggested that the genus first appeared around 2 million years ago, with its earliest fossils found in Florida,[15] while other authors suggest the earliest unambiguous appearance ofCuvieronius in the fossil record in North America dates to somewhat later, around 1.4 million years ago (Ma).[6]Cuvieronius wasextirpated from its northern range in North America over the course of theIrvingtonian after the arrival of theColumbian mammoth in North America around 1.3 Ma, presumably due tocompetitive exclusion by Columbian mammoths as well asmastodons, with its last well accepted records in Florida dating to around 500,000 years ago (though some authors have argued it persisted in this region into the Late Pleistocene[6]),[15] but persisted in southern North America (including Mexico) and Central America until the very end of the Pleistocene. During theGreat American Interchange,Cuvieronius and a relative,Notiomastodon, dispersed into South America.[19]Cuvieronius apparently reached South America considerably later thanNotiomastodon, with the oldest possible date being 760,000 ±30,000 years ago and the oldest confirmed date being 304,000 ±54,000 years ago, and had a much more restricted range, confined mostly to the Andes.[20]
In North America,Cuvieronius is known from the southern and southwestern United States with remains reported (spanning from the Early Pleistocene to Late Pleistocene) from North & South Carolina, Texas, Florida, Arizona, New Mexico and Oklahoma, as well as across Mexico. Fossils ofCuvieronius are widespread across Central America.[21][6][22] By the Late Pleistocene it had become considerably rarer and/orlocally extinct/extirpated across much of the northern part of its North American range,[15] and remains found near the town ofHockley in Texas nearHouston, which date to around 24,000 yearsBefore Present (BP), are the most recent findings north of Mexico.[22]
Many gomphothere remains in South America historically referred toCuvieronius actually refer toNotiomastodon, with many previous studies simply labeling fossils one or the other depending on location. Considering only localities definitely identified asCuvieronius, the range ofCuvieronius in South America is now considered to span the highAndes from Ecuador in the north, to Bolivia in the south, with the localities in the southern Andes in Chile and Argentina now thought to belong toNotiomastodon.[20]Cuvieronius was extirpated from South America by the end of the Late Pleistocene, with its youngest dates on the continent being around 44,000 years ago, before the arrival of people.[20]
Curiveronius became extinct at the end of the Pleistocene, approximately 12,000 years ago as part of theend-Pleistocene extinction event, simultaneously alongside most other large animals across the Americas. The extinction ofCuvieronius and other megafauna postdateshuman arrival in the Americas, which occurred several thousand years prior. At theEl Fin del Mundokill site in Sonora, Mexico, remains of an individual ofCuvierionius and another indeterminate gomphothere were found associated withClovis spear points, suggesting that hunting may have played a role in its extinction.[23][20] The site was initially suggested to date to 13,390 yearsBefore Present, however this date was later contested, and the site may be younger than this.[24] Some authors suggest that the species may have survived into the earlyHolocene in Central America, based onradiocarbon dated remains from southern-central Guatemala, though this dating is based onenamel toothapatite, which is more prone to date-altering contamination than dates based oncollagen.[11]
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