Barbourofelis

Barbourofelis is an extinct genus of large, carnivorous, mammals. They were a type of saber-toothed cat.
The genus was found in North America during the Miocene to Pleistocene. They lived from 13.6 5.3 million years ago (mya), which is about 8.3 million years. 
Its flattened saber teeth were protected by a bony flange from the lower jaw. It was a saber-toothed cat, but it was not a close relative of cats such as "Smilodon".
"Barbourofelis" has been difficult to classify. It was put in the Nimravidae by Schultz (1970) and Martin (1998).