Elbow-joint morphology in the North American 'cheetah-like' cat .

The North American cheetah-like cat is an extinct species that roamed the Pleistocene prairies 13 000 years ago. Although is more closely related to the cougar () than to the living cheetah (), it is believed that both and possess a highly specialized skeleton for fast-running, including limbs adapted for speed at the expense of restricting the ability of prey grappling. However, forelimb dexterity of has not been yet investigated. Here, we quantify the 3D-shape of the humerus distal epiphysis as a proxy for elbow-joint morphology in a sample of living cats to determine whether the extinct was specialized to kill open-country prey using predatory behaviour based on fast running across the prairies and steppe terrains of the North American Pleistocene. We show that had an elbow morphology intermediate to that of and , suggesting that had a less specialized pursuit predatory behaviour than . We propose that probably deployed a unique predatory behaviour without modern analogues. Our results bring into question the degree of ecomorphological convergence between and its Old World vicar .