Hoplophoneus primaevus belongs to Nimravidae, a family of faux cats. Nimravidae was the earliest cat-like organism to evolve, some 35 million years ago. This family clung on until it became extinct during the Late Miocene around 8 million years ago (Palmer & Cox 1997). H. primaevus specifically lived during the early Oligocene, 33.9-33.3 million years ago (http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=47108). It is thought that nimravids evolved alongside the ancestors of extant Felidae, as they show many of the same characteristics, but are not closely related phylogenetically. This was most likely a case of parallel evolution (Turner 1997).
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