About Smilodon

Smilodon, often called Sabre-toothed cat is an extinct genus of machairodontine. The sabre-toothed cat was endemic to North America and South America, living from the Early Pleistocene through Lujanian stage of the Pleistocene epoch (2.5 mya—10,000 years ago).
The nickname "sabre-tooth" refers to the extreme length of their maxillary canines. Despite the colloquial name of "sabre-toothed tiger", Smilodon is not a tiger, which belongs to the subfamily Pantherinae. The name Smilodon comes from Greek: σμίλη, smilē, "knife" and Greek ὀδoύς (odoús), "tooth", Genitive: ὀδoύς, ὀδόντος,odóntos.
The genus Smilodon was described by the Danish naturalist and palaeontologist Peter Wilhelm Lund in 1841. He found the fossils of Smilodon populator in caves near the small town of Lagoa Santa, in the state of Minas Gerais, Brazil.
A number of Smilodon species have been described, but today usually only three are recognized.

• Smilodon gracilis, 2.5 million-500,000 years ago; the smallest and earliest species (estimated to have been only 55 to 100 kg (120 to 220 lb)) was the successor of Megantereon in North America, from which it probably evolved. The other Smilodon species probably derived from this species.
• Smilodon fatalis, 1.6 million-10,000 years ago, replaced Smilodon gracilis in North America and invaded western South America as part of the Great American Interchange. In size it was between Smilodon gracilis and Smilodon populator, and about the same as the largest surviving cat, the Siberian Tiger. This species was about 1 m high at the shoulder and is estimated to have ranged from 160 to 280 kg (350 to 620 lb). Sometimes two additional species are recognized, Smilodon californicus and Smilodon floridanus, but usually they are considered to be subspecies of Smilodon fatalis.
• Smilodon populator ("the devastating Smilodon"), 1 million-10,000 years ago; occurred in the eastern parts of South America and was the largest species of all machairodonts. It was much larger than its cousins, S. fatalis and S. gracilis, possessing a massive chest and front legs, and is the largest known variety of sabre-toothed cat. It was more than 1.22 m (48 in) high at the shoulder, 2.6 m (100 in) long on average and had a 30 cm (12 in) tail. With an estimated weight of 360 to 455 kg (790 to 1,000 lb), it was among the heaviest known felids. Its upper canines reached 30 cm (12 in) and protruded up to 17 cm (6.7 in) out of the upper jaw. Genetic evidence suggests that Smilodon populator and other members of the genus diverged from the main lineage of modern cats (subfamily Felinae) around 14-18 million years ago.

Smilodon populator is also known from the famous cave site of Ultima Esperanza, with well-preserved remains retaining endogenous DNA.

Wikipedia contributors, "Smilodon", the free encyclopedia, Retrieved 10:30, April 26, 2011 from
http://en.wikipedia.org/wiki/Smilodon