Monday, January 16, 2012

ear piercings types diagram

It contains some 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. Sometimes other carnivorous mammals with elongated teeth are also called saber-toothed cats, although they do not belong to the felids. Besides the machairodonts, saber-toothed predators arose in Nimravidae, Barbourofelidae, Creodonta (Machaeroides) and even in a group of sparassodont metatherians (Thylacosmilus).

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 machairodontid 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 which also bore long sabreteeth. Traditionally three different tribes of machairodontines were recognized, the Smilodontini with typical dirk-toothed forms like Megantereon and Smilodon, the Machairodontini or Homotherini with scimitar-toothed cats like Machairodus or Homotherium and the Metailurini, containing generea like Dinofelis and Metailurus. However, recently the Metailurini are grouped within another felid subfamily, the Felinae, not into the Machairodontinae. The last machairodontine genera Smilodon and Homotherium did not disappear until late in the Pleistocene, roughly 10.000 years ago in the Americas.