Miracinonyx

Called the American cheetah, this cat is a mystery. Living from three million to ten or twenty thousand years ago in north America, these cats are known only from fragments of skeletons. They lived in north America, and their specific place in the evolution of cats and cheetahs is unclear. Though they are similar to true cheetahs (those of the genus Acinonyx) in the fact that their faces were shortened and nasal cavities expanded, along with lengthened legs, but they were not exactly like cheetahs, and the two were on seperate ocean devided continents.

Two species have been identify; M. inexpectatus and M. Trumani. Trumani was the most similar to modern cheetahs in morphology, living on the prairies and plains, they were likely predators of [[pronghorns[[ and the reason why pronghorns run so swiftly, their 60 mph top speed much more than is needed to outrun modern predators such as pumas and wolves. Trumani looks as if it could be somehow related to cheetahs or a cheetah ancestor, yet there is always the possibility that it is an example of co-evolution. As grasslands became more common in both Africa and America, perhaps separate cat species from both continents evolved to catch the new fleet footed herbivores.

Yet inexpectatus is more similar to the puma, their proportions between that of pumas and modern cheetahs. They had fully retractable claws, and were likely fast than a puma, but better adept at climbing than a cheetah.

So the question remains of how all this information fits together. Weather Miracinonyx was related to cheetahs or simply another brand of fast feline, how pumas are related to them all, even if there were actually three species of miracinonyx, are all debateable. Until additional fossils are found, it is unlikely that anything definite will ever be decided on.