Range and diet diversity in the Pleistocene American "cheetah," Miracinonyx trumani.

The extinct "American cheetah" (Miracinonyx trumani) has long been considered a North American ecological analog of the African cheetah1,2 (Acinonyx jubatus) based on convergent cursorial morphology, yet this paradigm rests on limited data3 and untested assumptions about its evolutionary relationships and ecology.2,4 Here, we generate nuclear paleogenomes from M. trumani specimens from Wyoming (∼23 kya; thousand years ago) and Yukon (∼31 kya), definitively placing this enigmatic felid within the evolutionary tree of cats. Phylogenomic analyses confirm M. trumani as sister to pumas (Puma concolor), not cheetahs, with a divergence of ∼2.6 million years ago (mya) during rapid Pliocene-Pleistocene climate oscillations. The Yukon specimens extend the species' known range2 by over 20° latitude into the Arctic, and stable isotope analyses reveal striking ecological differentiation, with the Yukon population occupying an elevated trophic position consistent with exploitation of anadromous fish, while the Wyoming population functioned as a generalist terrestrial predator. This evidence suggests that M. trumani exhibited remarkable ecological versatility, while loss-of-function mutations in circadian genes may reflect relaxed constraints on circadian regulation. Together, these findings underscore how morphological convergence can obscure the true diversity and complexity of extinct megafaunal ecosystems.