Mentoclaenodon is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of condylarth

Condylarth

Condylarthra is an order of extinct placental mammals known primarily from the Paleocene and Eocene epochs. Condylarths are among the most characteristic Paleocene mammals and they illustrate the evolutionary level of the Paleocene mammal fauna....

 mammals.

Mentoclaenodon had large upper canines (sabre-teeth) like some Miocene

Miocene

The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

 and Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 big cats. In fact,the Arctocyonid Mentoclaenodon, its close relative Anacodon, and the Creodont Machaeroides

Machaeroides

Machaeroides is a genus of sabre-toothed creodont that lived during the Eocene. Its fossils were found in the U.S. state of Wyoming. It is the earliest known sabre-toothed mammal.-Description:...

 were the first mammals to develop saber-teeth. (The saber-tooth Gorgonops

Gorgonops

Gorgonops is an extinct genus of therapsid which lived about 255-250 million years ago, during the latest part of the Permian Period. It was a typical representative of the suborder Gorgonopsia, the dominant predators of their day, which in the largest forms grew to over four metres long...

ians were semi-reptilian). Its fossils have been found in Europe, in Cernay levels and Walbeck, Germany. With an estimated skull length of 15 cm.

Mentoclaenodon was one of the largest European mammals during the Paleocene. It is also among the first mammal predators to prey on other mammals. Mentoclaenodon and its ancestors reigned from the Cretaceous

Cretaceous

The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 to the Paleocene

Paleocene

The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...

. But by the early Eocene they were replaced by the Creodonts and the early Carnivores such as Miacis

Miacis

The 'genus' Miacis contains extinct species of carnivorous mammals that appeared in the late Paleocene and continued through the Eocene. The genus Miacis is not monophyletic but a diverse collection of species that belong to the stemgroup within the Carnivoramorpha...

.