Which prehistoric big cat had the scientific name Panthera atrox?

The prehistoric big cat with the scientific name Panthera atrox was the American lion.

The American lion was an extinct pantherine cat that lived across much of North America during the Late Pleistocene. Its species name, atrox, is Latin for “cruel” or “fearsome.” Fossils have been found from Alaska and Canada southward through the United States, and the Rancho La Brea Tar Pits in California have produced many important specimens.

Its classification has a complicated history. It was first described as Felis atrox, later moved into Panthera and at times treated as a subspecies of the modern lion, Panthera leo. Genetic evidence indicates that the living lion is its closest living relative, while the American lion likely formed a sister lineage to Eurasian cave lions after an ancient population became isolated in North America.

The American lion was not the same animal as the Eurasian cave lion, Panthera spelaea, although the two were closely related. It was also much larger than many modern lions, with estimates for some males reaching more than 450 kilograms. The species disappeared near the end of the Pleistocene, around the time North American megafauna declined.