American cheetah
Temporal range: 2.6–0.011 Ma
File:Miracinonyx trumani.jpg
Miracinonyx trumani
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Felidae
Subfamily: Felinae
Genus: Miracinonyx
Adams (1979)
  • M. inexpectatus Cope (1895)
  • M. trumani Orr (1969)

The American cheetah, Miracinonyx, is an extinct genus of at least two feline species morphologically similar to the modern cheetah which were endemic to North America during the Pleistocene epoch (2.6 Ma—12,000 years ago).[1] These cats are known only from fragments of skeletons.

The two species commonly identified are Miracinonyx inexpectatus and M. trumani. Sometimes a third species, M. studeri, is added to the list, but it is more often listed as a junior synonym of M. trumani. Both species are similar to the modern cheetah, with faces shortened and nasal cavities expanded for increased oxygen capacity, and legs proportioned for swift running. However, these similarities may not be inherited from a common ancestor, but result from either parallel or convergent evolution. These were larger than a modern cheetah and similar in size to a modern northern cougar. Body mass was typically around 70 kg (150 lb) with a head-and-body length of 170 cm (67 in), tail length of around 92 cm (36 in) and a shoulder height of 85 cm (33 in).[2] Large specimens could have weighed more than 95 kg (209 lb).[3]

Taxonomy and evolution

Research into the American cheetah has been contradictory. It was originally believed to be an early cougar representative, before being reclassified in the 1970s as a close relative of the cheetah.[4] This suggested that ancestors of the cheetah diverged from the Puma lineage in the Americas and migrated back to the Old World, a claim repeated as recently as Johnson et. al. (2006).[5] Other research by Barnett, however, examining mitochondrial DNA and re-analyzing morphology, has suggested reversing the reclassification: the American cheetah developed cheetah-like characteristics through convergent evolution, but it is most closely related to Puma and not to the modern cheetah of Africa and Asia.[6] The supposed American origin of the modern cheetah is thus equivocal; however, it is believed to have evolved from cougar-like ancestors, whether in the Old or New World.

The cougar and M. trumani are believed to have split from a cougar-like ancestor around three million years ago;[6] where M. inexpectatus fits in is unclear, although it likely is a more primitive version of M. trumani.[7]

Miracinonyx trumani

M. trumani was the most similar to true cheetahs in morphology. Living on the prairies and plains of western America, it was likely a predator of hoofed plains animals such as the pronghorn. In fact, predation by Miracinonyx is thought to be the reason that pronghorns evolved to run so swiftly, their 60 mph top speed being much more than needed to outrun extant American predators such as cougars and gray wolves.[8]

Miracinonyx inexpectatus

Template:Ref improve section M. inexpectatus was more similar to the cougar than was M. trumani, its proportions between that of the cougar and M. trumani.[citation needed] It had fully retractable claws, and with its lighter build, the Miracinonyx inexpectatus was likelyTemplate:Vague faster than the cougar. Due to the retractable claws, it is also possible that it was more adept at climbing than M. trumani.[1][citation needed]

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  1. ^ PaleoBiology Database: Miracinonyx, basic info
  2. ^ San Diego Zoo Factsheet
  3. ^ Caro, T.M. (1994). Cheetahs of the Serengeti Plains: Group Living in an Asocial Species. Chicago: University of Chicago Press. p. 500. ISBN 0226094332. 
  4. ^ Adams, Daniel B. (14 September 1979). "The Cheetah: Native American" (abstract). Science. 205 (4411): 1155–1158. PMID 17735054. doi:10.1126/science.205.4411.1155. Retrieved 2007-06-04. 
  5. ^ Johnson, W.E., Eizirik, E., Pecon-Slattery, J., Murphy, W.J., Antunes, A., Teeling, E. & O'Brien, S.J. (6 January 2006). "The Late Miocene radiation of modern Felidae: A genetic assessment" (abstract). Science. 311 (5757): 73–77. PMID 16400146. doi:10.1126/science.1122277. Retrieved 2007-06-04.  More than one of |number= and |issue= specified (help)
  6. ^ a b Barnett, Ross; Ian Barnes, Matthew J. Phillips1, Larry D. Martin, C. Richard Harington, Jennifer A. Leonard, and Alan Cooper (9 August 2005). "Evolution of the extinct Sabretooths and the American cheetah-like cat". Current Biology. 15 (15): R589–R590. PMID 16085477. doi:10.1016/j.cub.2005.07.052. Retrieved 2007-06-04.  Cite uses deprecated parameter |coauthors= (help)
  7. ^ Haaramo, Mikko (2005-11-15). "Mikko's Phylogeny Archive - Felidae: Felinae – small cats". Archived from the original on 27 March 2007. Retrieved 2007-02-20. 
  8. ^ Byers, John (1998). American Pronghorn: Social Adaptations and the Ghosts of Predators Past. Chicago University Press. p. 318. ISBN 978-0-226-08699-6. 

External links

Hartmann zebra hobatere S This article is part of Project Mammal Genera, a All Birds project that aims to write comprehensive articles on each genus, including made-up genera.
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