the taxonomic position of lions in Central Africa may require revision. Fossil records Other lion subspecies or sister species to the modern lion existed in prehistoric times: P. l. sinhaleyus was a fossil carnassial excavated in Sri Lanka, which was attributed to a lion. It is thought to have become extinct around 39,000 years ago. P. leo fossilis was larger than the modern lion and lived in the Middle Pleistocene. Bone fragments were excavated in caves in the United Kingdom, Germany, Italy and Czech Republic. P. spelaea, or the cave lion, lived in Eurasia and Beringia during the Late Pleistocene. It became extinct due to climate warming or human expansion latest by 11,900 years ago. Bone fragments excavated in European, North Asian, Canadian and Alaskan caves indicate that it ranged from Europe across Siberia into western Alaska. It likely derived from P. fossilis, and was genetically isolated and highly distinct from the modern lion in Africa and Eurasia. It is depicted in Paleolithic cave paintings, ivory carvings, and clay busts. P. atrox, or the American lion, ranged in the Americas from Canada to possibly Patagonia. It arose when a cave lion population in Beringia became isolated south of the Cordilleran Ice Sheet about 370,000 years ago. A fossil from Edmonton dates to 11,355 ± 55 years ago. Evolution The Panthera lineage is estimated to have genetically diverged from the common ancestor of the Felidae around to , and the geographic origin of the genus is most likely northern Central Asia. Results of analyses differ in the phylogenetic relationship of the lion; it was thought to form a sister group with the jaguar (P. onca) that diverged , but also with the leopard (P. pardus) that diverged to . Hybridisation between lion and snow leopard (P. uncia) ancestors possibly continued until about 2.1 million years ago. The lion-leopard clade was distributed in the Asian and African Palearctic since at least the early Pliocene. The earliest fossils recognisable as lions were found at Olduvai Gorge in Tanzania and are estimated to be up to 2 million years old. Estimates for the divergence time of the modern and cave lion lineages range from 529,000 to 392,000 years ago based on mutation rate per generation time of the modern lion. There is no evidence for gene flow between the two lineages, indicating that they did not share the same geographic area. The Eurasian and