El término «dientes de sable» es un término genérico que se usa para describir a numerosas especies de mamíferos dotados de enormes caninos que vivieron durante diferentes épocas del Cenozoico. Estas especies adquirieron sus característicos dientes de sable de forma totalmente independiente. La morfología de los dientes es un excelente ejemplo de evolución convergente, ya que ha ocurrido repetida e independientemente en por lo menos cuatro grupos diferentes de mamíferos: los macairodontes (Machairodontinae), una subfamilia de los félidos que incluye al famoso Smilodon; los nimrávidos (Nimravidae), una familia emparentada con los felinos, pero diferente; y finalmente, un par de casos aislados dentro de los creodontos (que no son considerados carnívoros auténticos) y los tilacosmílidos, una familia extinta de metaterios sudamericanos.

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A saber-toothed cat (alternatively spelled sabre-toothed cat) is any member of various extinct groups of predatory mammals that were characterized by long, curved saber-shaped canine teeth. The large maxillary canine teeth extended from the mouth even when it was closed. The saber-toothed cats were found worldwide from the Eocene epoch to the end of the Pleistocene epoch (42 mya – 11,000 years ago), existing for about 42 million years. One of the best known genera is Smilodon, species of which, especially S. fatalis, are popularly referred as a "saber-toothed tiger," a genus within the subfamily Machairodontinae of the carnivoran family Felidae. Extant members of Felidae include cats of the subfamilies Felinae and Pantherinae. However, usage of the word cat is a misnomer, as most saber-toothed "cats" are not related to modern cats of Felidae: instead, many are members of other feliform carnivoran families, such as Barbourofelidae and Nimravidae; the oxyaenid "creodont" genera Machaeroides and Apataelurus; and two lineages of metatherian mammals, the thylacosmilids and deltatheroideans, which are more closely related to marsupials than to the placental mammals of the other orders mentioned. In this regard, saber-toothed cats can be viewed as examples of convergent evolution. Of the feliform lineages, the family Nimravidae is the oldest, entering the landscape around 42 mya and becoming extinct by 7.2 mya. Barbourofelidae entered around 16.9 mya and were extinct by 9 mya. These two would have shared some habitats.

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