Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae (true cats). They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million until about 11,000 years ago. The Machairodontinae contain many of the extinct predators commonly known as "saber-toothed cats", including the famed genus Smilodon, as well as other cats with only minor increases in the size and length of their maxillary canines. The name means "dagger-tooth", from Greek μάχαιρα (machaira), sword. Sometimes, other carnivorous mammals with elongated teeth are also called saber-toothed cats, although they do not belong to the felids. Besides the machairodonts, other saber-toothed predators also arose in the nimravids, barbourofelids, machaeroidines, hyaenodonts and even in two groups of metatherians (the thylacosmilid sparassodonts and the deltatheroideans). Μαχαιροῦς, from Ancient Greek: μάχαιρα, lit. 'makhaira', means a sword. The Machairodontinae originated in the early or middle Miocene of Africa. The early felid Pseudaelurus quadridentatus showed a trend towards elongated upper canines, and is believed to be at the base of the machairodontine evolution. The earliest known machairodont genus is the middle Miocene Miomachairodus from Africa and Turkey. Until the late Miocene, machairodontines co-existed at several places together with barbourofelids, archaic large carnivores that also bore long sabre-teeth. Traditionally, three different tribes of machairodontines were recognized, the Smilodontini with typical dirk-toothed forms, such as Megantereon and Smilodon, the Machairodontini or Homotherini with scimitar-toothed cats, such as Machairodus or Homotherium, and the Metailurini, containing genera such as Dinofelis and Metailurus. However, some have recently regrouped the Metailurini within the other felid subfamily, the Felinae, along with all modern cats. The last machairodontine genera, Smilodon and Homotherium, did not disappear until late in the Pleistocene, roughly 10,000 years ago in the Americas.