None of the following taxa
have been entered into the large reptile tree yet. Still waiting for higher resolution data and I’m a little shy about using such little skull data for the North American ‘cheetah’ (Fig. 1). The following study appears to make a good case on its face, but it has not been tested.
van Valkenburgh et al. 1990
discussed the relationships of the North American cheetah-like cat, Miracinonyx (originally Acinonyx studeri) with various other taxa, including Felis (the cat), Puma (the North American mountain lion) and Acinonyx (the African cheetah). The authors found “a minimum of ten features of the skull and post-cranal skeleton” that distinguished New and Old World cheetahs when they erected the new generic name. They also distinguish Puma from Miracinonyx “in limb proportions, slenderness of the long bones, and aspects of the nasomaxillary region of the skull.”
So, is Miraciconyx a cheetah or a puma?
Maybe there’s a third possibility. VanValkenburgh et al. 2006 recovered two intercontinental Miraciconyx taxa between Puma and Acinonyx, the African cheetah. The latest published answer is: the North American ‘cheetah’ is transitional between the puma and cheetah.
Distinct from Puma
the North American cheetah has a relatively smaller head, longer, slender limbs, and reduced canines. These traits are also found in Old World cheetahs.
According to Wikipedia
“Extinct North American cats resembling the cheetah had historically been assigned to Felis, Puma or Acinonyx. However, a phylogenetic analysis in 1990 placed these species under the genus Miracinonyx. Miracinonyx exhibited a high degree of similarity with the cheetah. However, in 1998, a DNA analysis showed that Miracinonyx inexpectatus, M. studeri, and M. trumani (early to late Pleistocene epoch), found in North America, are more closely related to the cougar than modern cheetahs (Mattern and McLennan 2000).”
DNA is affected by biological influences
found on continents (remember Afrotheria?). A transitional taxon is, by definition basal to one, ancestral to another, so which Miracinonyx is closer to cheetahs may depend on the distance from North America toward Africa. Likely there is a gradient of Miracinonyx specimens from one point on Earth to the other. That’s speculation. It needs testing.
Mattern MY and McLennan DA 2000. “Phylogeny and speciation of felids”. Cladistics. 16 (2): 232–53. doi:10.1111/j.1096-0031.2000.tb00354.x
van Valkenburgh B, Grady F and Kurtén B 1990. The Plio-Pleistocene cheetah-like cat Miracinonyx inexpectatus of North American. Journal of Vertebrate Paleontology 10(4):434–454.