Acinonychini

Acinonychins Temporal range: Late Miocene - Holocene, 6.7–0 Ma PreЄ Є O S D C P T J K Pg N
Cougar (Puma concolor)
Cheetah (Acinonyx jubatus)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Class:	Mammalia
Order:	Carnivora
Family:	Felidae
Subfamily:	Felinae
Tribe:	Acinonychini Pocock, 1917
Genera
†Viretailurus Hemmer, 1965 Herpailurus Severtzov, 1858 †Miracinonyx Adams, 1979 Puma Jardine, 1834 †Sivapanthera Kretzoi, 1929 Acinonyx Brookes, 1828

†Viretailurus Hemmer, 1965
Herpailurus Severtzov, 1858
†Miracinonyx Adams, 1979
Puma Jardine, 1834
†Sivapanthera Kretzoi, 1929
Acinonyx Brookes, 1828

The feline tribe Acinonychini contains at least two genera: Puma (containing two species, the cougar and the jaguarundi) and Acinonyx (only one species, the cheetah, has survived). In addition to these three extant species, there is a handful of extinct fossil species that have been found in Eurasia and the Americas. The evolutionary relationships of these cats still needs to be worked out, with the main focus being the placement of the extinct species in relation to the extant species and where cheetahs evolved. While cheetahs and cougars are big cats, they are more closely related to house cats than they are to lions and leopards.

Prior to the mid 1990s the cheetahs were placed in the monotypic subfamily Acinonychinae due to their anatomical specializations for their cursorial nature. Both the cougar and jaguarundi were classified in the genus Felis along with most of the purring cats. In the 1990s, the first molecular evidence based on mitochondrial DNA, nuclear DNA and chromosomal data found that the cheetah is nested among the purring cats, wit cougars and jaguarundis their closest relatives. As a result, cougars and jaguarundis were reclassified in the genus Puma and Acinonychinae is recognized as a junior synonym of Felinae. More advanced molecular studies based on genomic data has found strong support for this grouping. According to the current data, acinonychins diverged from other cats around 6.7 million years ago. The cheetah was the first to diverge from Puma around 4.9 million years ago. From there the cougar and jaguarundi split off 4 million years ago. In addition to the molecular work, various morphological studies that focused on the cranium have supported the relationship between Puma and Acinonyx. While the jaguarundi is classified in the genus Puma, the species differs from cougars due to size and anatomical differences, which results in some authors placing them in their own genus, Herpailurus.