| Acinonyx | |
|---|---|
 | |
| Cheetah (Acinonyx jubatus) | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Felidae |
| Subfamily: | Felinae |
| Genus: | Acinonyx Brookes, 1828 |
| Type species | |
| Felis jubata Schreber, 1775 | |
| Species | |
| Synonyms | |
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Acinonyx is agenus that is within theFelidaefamily,[1] also known as the cat family. The only livingspecies of the genus and most commonly known, thecheetah (A. jubatus) inhabits the opengrasslands of Africa and Asia along with parts of Iran.[2] This genus represents a highly adaptedlineage within the felids, which specialize in speed andopen-terrain hunting. Evidence suggest theAcinonyx genus evolved from other felineancestors early on, to become specialized in stealth and running.[3]
The main reasons for all but one species going extinct revolve aroundclimate changes, humans driving these species out of their habitats, and theirprey populations shrinking. Climate drastically changed starting in thePleistocene period, making it difficult to survive in openterrain andgrasslands upon which these cats depend.[4] Humancivilization also began to change and expand resulting in lots of these species to lose their home or hunting grounds. This also forced some species to be isolated making reproducing more difficult.[3] Another factor of humans expanding was the lack of prey for these cats; their prey were being hunted by humans or being forced from their habitats. These problems played a huge role in theextinction of the historicAcinonyx species.[1]
Fossil remains related to cheetah-like cats wereexcavated that date back to the latePliocene andMiddle Pleistocene,[5] indicating a wide time range. These cats occurred across much of the old world 10,000 years ago, some extinct species such asA. pardinensis andA. intermedius were found in parts ofEurope andAsia.[4] Several similar species classified in the genusMiracinonyx lived in North America at the same time; these may have been more closely related to the genusPuma.[2]
A primary characteristic of this genus are bodiesadapted for speed and swiftness; however the species at the time were much different inmorphology. Species found 10,000 years ago show a large and vigorous build for these cats compared to the cheetah which has accommodated to fast prey, with a much slimmer build enabling a quick pursuit.[4]Acinonyx species are also unable to retract theirclaws fully, this can be a disadvantage in some cases. However claws give extra traction while running.[6]
Acinonyx was proposed byJoshua Brookes in 1828.[7]
The word Acinonyx isgreek, the first portion of "akinetos" translates to "unmoved" or "motionless" and the second portion "onyx" translates to "nail" or "claw".[8] Which represents one the main traits used to recognize this genus, not being able to retract their claws fully.[6]
Between the late 18th century and the early 20th century, the followingAcinonyx species andsubspecies were described:[1]
In 1993,Acinonyx was placed in themonophyletic subfamily Acinonychinae.Molecular phylogenetic analysis has shown that it is thesister group of the genusPuma, and it is now placed within the subfamilyFelinae.[1]
In addition, the followingfossilAcinonyx species were described:
TheAsiatic cheetah ("Acinonyx jubatus venaticus") is part of the last surviving lineages that are outside ofAfrica. Recent genetic studies have shown that thissubspecies separated from African populations roughly 32,000 to 67,000 years ago, suggesting a prolonged adaptation to dry landscapes.[6]
The "Linxia Cheetah" ("A. kurteni") was initially described by Christiansen and Mazák in 2009 on the basis of a skull from Pliocene strata in China, and touted as the most primitive member of the genus.[17] In 2012, "A. kurteni" was invalidated as a species when theholotype was determined to be a forgery composed of Miocene-aged fragments.[18][19]
The extended duration and broad range offossil records suggests the longevolutionary presence across the old world into the present day. The fossils also suggest how the genus Acinonyx once ranged widely acrossEurasia, eventually population declining to climatic shifts and the habitat being broken into different locations due to human activities.[4]
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