Research overview: the contested identity of the American lion, Panthera atrox

This overview examines the long-running debate over what the American lion, Panthera atrox, actually was. Since its description from Pleistocene North America, researchers have variously regarded it as a giant subspecies of the modern lion, a close relative of the jaguar, or a distinct species in its own right. Skeletal studies have noted both lion-like and jaguar-like features, while ancient DNA has clarified its affinities. The survey reviews the morphological arguments, the genetic evidence linking atrox to the lion lineage and especially to the Eurasian cave lion, and the questions that remain about its precise status. It frames Panthera atrox as a case study in how combining anatomy and palaeogenetics can resolve, but also complicate, the classification of an extinct big cat.