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Nimravidae is an extinct family of , sometimes known as false saber-toothed cats, whose are found in North America, Africa, and Eurasia. Not considered to belong to the true cats (family Felidae), the nimravids are generally considered closely related and classified as a distinct family in the suborder Feliformia. Fossils have been dated from the Middle Eocene through the Late Miocene epochs (Bartonian through Messinian stages, 41.03–7 million years ago), spanning about .
The barbourofelids, were once classified as a subfamily of the Nimravidae, reassigned to their own distinct family Barbourofelidae in 2004. However, since 2020, the majority of experts consider barbourofelids as nimravids.
Nimravids are placed in tribes by some authors to reflect closer relationships between genera within the family. Some nimravids evolved into large, toothed, cat-like forms with massive flattened upper canines and accompanying mandibular flanges. Some had dentition similar to felids, or modern cats, with smaller canines. Others had moderately increased canines in a more intermediate relationship between the saber-toothed cats and felids. The upper canines were not only shorter, but also more conical, than those of the true saber-toothed cats (Machairodontinae). These nimravids are referred to as "false saber-tooths".
Not only did nimravids exhibit diverse dentition, but they also showed the same diversity in size and morphology as cats. Some were leopard-sized, while some like as E. adelos the size of small . One had the short face, rounded skull, and smaller canines of the modern cheetah, and one, Nanosmilus, was only the size of a small bobcat.
The Barbourofelidae were for a while no longer included in Nimravidae, following elevation to family as sister clade to the true cats (family Felidae). (2025). 9780199234455, Oxford University Press. ISBN 9780199234455 However, majority of recent studies have returned them to Nimravidae, with one study suggesting they are part of Nimravinae.
| Family Extinction | ||
| † Nimravus |
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| † Nanosmilus |
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A 2021 study divides Nimravidae into Hoplophoninae and Nimravinae, the latter including the bulk of species in addition to barbourofelids.
Phylogeny of Nimravidae from the 2022 description of Pangurban:
Nimravids appeared in the middle of the Eocene epoch, about 40 Mya, in North America and Asia. The global climate at this time was warm and wet, but was trending cooler and drier toward the late Eocene. The lush forests of the Eocene were transforming to scrub and open woodland. This climatic trend continued in the Oligocene, and nimravids evidently flourished in this environment. North America and Asia were connected and shared much related fauna. Europe in the Oligocene was more of an archipelago than a continent, though some land bridges must have existed, for nimravids also spread there. If considered members of the family, Barbourofelins likely from Nimravinae migrated into Africa during the Oligocene. The presence of large Hyaenodonta prevented them from reaching a large size but were able to carve a niche due to their dental morphology. Eventually, they dispersed from Africa into Eurasia and later into North America.
Barbourfelids, if valid members of the family, went extinct around 7 million years ago, during the Late Miocene, for unknown reasons. Antón Mauricio suggested competition with machairodontinae such as Machairodus and Nimravides, may have contributed to their extinction, as barbourofelids were widely successful despite the wider expansion of grasslands. However, Paul Barret has contested this hypothesis because of the limited temporal overlap between both clades. In addition, Albanosmilus, the last genus to go extinct in Eurasia, was also able to coexist and compete with machairodonts Amphimachairodus and Machairodus in some localities, in some cases over a million years. Other experts suggested it was more likely they went extinct because of the faunal overturn during the Late Miocene due to the wider expansion of grasslands.
Although some nimravids physically resembled the saber-toothed cats, such as Smilodon, they were not closely related, but evolved a similar form through parallel evolution. They possessed synapomorphies with the barbourofelids in the cranium, mandible, dentition, and postcranium. They also had a downward-projecting flange on the front of the mandible as long as the canine teeth, a feature that also convergently evolved in the saber-toothed sparassodont Thylacosmilus.
A 2021 study has shown that a sizeable number of species developed feline-like morphologies in addition to saber-toothed taxa.
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