Felidae Oligocene, about 25 million years ago, with the appearance of "Proailurus" and "Pseudaelurus". The latter species complex was ancestral to two main lines of felids, the cats in the extant subfamilies and a third major group of extinct cats, which are assigned to the subfamily Machairodontinae. The machairodonts included the saber-toothed cats such as the "Smilodon". The "false sabre toothed cats", the Barbourofelidae and Nimravidae, are not true cats, but are closely related and together with Felidae and other cat-like carnivores (hyaenas, viverrids and mongooses) make up the feliform carnivores. Results of mitochondrial analysis indicates that all the Felidae descended
Felidae Adult tigers actually display elongated rosettes that now appear as stripes. Adult lions seem to lack any distinctive markings altogether. Both juvenile tigers and lions, however, display partial rosettes. This ancestral character state appears only during these early stages, supporting the notion that ontogeny reflects phylogeny. The rosette patterns found on snow leopards, jaguars, and leopards all have a common origin. Fossil occurrences indicate that the Felidae arrived in North America about 10 million years later than the Canidae, and about 20 million years later than the Ursidae and the Nimravidae. Traditionally, five subfamilies have been distinguished within the Felidae