The Knife Tooth Cat (Machairodus) is a genus of large machairodont or ''saber-toothed cat'' that lived in Africa, Eurasia and North America during the late Miocene. It is the animal from which the subfamily Machairodontinae gets its name and has since become a wastebasket taxon over the years as many genera of sabertooth cat have been and are still occasionally lumped into it.
Smilodon is a genus of felids belonging to the extinct subfamily Machairodontinae. It is one of the best known saber-toothed predators and prehistoric mammals. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats. Smilodon lived in the Americas during the Pleistocene epoch. The genus was named in 1842 based on fossils from Brazil; the generic name means "scalpel" or "two-edged knife" combined with "tooth". Three species are recognized today: S. gracilis, S. fatalis, and S. populator. The two latter species were probably descended from S. gracilis, which itself probably evolved from Megantereon. The hundreds of specimens obtained from the La Brea Tar Pits in Los Angeles constitute the largest collection of Smilodon fossils.
A saber-tooth is any member of various extinct groups of predatory therapsids, predominantly carnivoran mammals, that are characterized by long, curved saber-shaped canine teeth which protruded from the mouth when closed. Saber-toothed mammals have been found almost worldwide from the Eocene epoch to the end of the Pleistocene epoch.
Nimravidae is an extinct family of carnivorans, sometimes known as false saber-toothed cats, whose fossils are found in North America and Eurasia. Not considered to belong to the true cats, 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, spanning about 33.2 million years.
Machairodontinae is an extinct subfamily of carnivoran mammals of the family Felidae. They were found in Asia, Africa, North America, South America, and Europe from the Miocene to the Pleistocene, living from about 16 million until about 10,000 years ago.
A sagittal crest is a ridge of bone running lengthwise along the midline of the top of the skull of many mammalian and reptilian skulls, among others. The presence of this ridge of bone indicates that there are exceptionally strong jaw muscles. The sagittal crest serves primarily for attachment of the temporalis muscle, which is one of the main chewing muscles. Development of the sagittal crest is thought to be connected to the development of this muscle. A sagittal crest usually develops during the juvenile stage of an animal in conjunction with the growth of the temporalis muscle, as a result of convergence and gradual heightening of the temporal lines.
Paraceratherium is an extinct genus of hornless rhinocerotoids belonging to the family Paraceratheriidae. It is one of the largest terrestrial mammals that has ever existed and lived from the early to late Oligocene epoch. The first fossils were discovered in what is now Pakistan, and remains have been found across Eurasia between China and the Balkans. Paraceratherium means "near the hornless beast", in reference to Aceratherium, the genus in which the type species P. bugtiense was originally placed.
Thylacosmilus is an extinct genus of saber-toothed metatherian mammals that inhabited South America from the Late Miocene to Pliocene epochs. Though Thylacosmilus looks similar to the "saber-toothed cats", it was not a felid, like the well-known North American Smilodon, but a sparassodont, a group closely related to marsupials, and only superficially resembled other saber-toothed mammals due to convergent evolution. A 2005 study found that the bite forces of Thylacosmilus and Smilodon were low, which indicates the killing-techniques of saber-toothed animals differed from those of extant species. Remains of Thylacosmilus have been found primarily in Catamarca, Entre Ríos, and La Pampa Provinces in northern Argentina.
Hyaenodon ("hyena-tooth") is an extinct genus of carnivorous placental mammals from extinct tribe Hyaenodontini within extinct subfamily Hyaenodontinae, that lived in Eurasia and North America from the middle Eocene, throughout the Oligocene, to the early Miocene.
Galesaurus is an extinct genus of carnivorous cynodont therapsid that lived between the Induan and the Olenekian stages of the Early Triassic in what is now South Africa. It was incorrectly classified as a dinosaur by Sir Richard Owen in 1859.
Dinictis is a genus of the Nimravidae, an extinct family of feliform mammalian carnivores, also known as "false saber-toothed cats". Assigned to the subfamily Nimravinae, Dinictis was endemic to North America from the Late Eocene to Early Miocene epochs, existing for about 16.8 million years.
Nimravus is an extinct genus of "false" saber-toothed cat in the family Nimravidae known from North America and Europe during the Oligocene epoch 33.3—26.3 mya, existing for approximately 7 million years. Not closely related to true saber-toothed cats, they evolved a similar form through parallel evolution. Fossils have been uncovered in the western U.S. from Oregon to southern California and Nebraska.
Eusmilus is a prehistoric genus of nimravid that lived in Europe and North America during the Late Eocene to Early Oligocene epochs.
Hoplophoneus is an extinct genus of the family Nimravidae, endemic to North America during the Late Eocene to Early Oligocene epochs, existing for approximately 6 million years.
Dinailurictis was an extinct nimravid carnivoran belonging to the subfamily Nimravinae. It was named in 1922, with subsequent material being recovered from middle Oligocene deposits across France and Spain.
The cat gap is a period in the fossil record of approximately 25 million to 18.5 million years ago in which there are few fossils of cats or cat-like species found in North America. The cause of the "cat gap" is disputed, but it may have been caused by changes in the climate, changes in the habitat and environmental ecosystem, the increasingly hypercarnivorous trend of the cats, volcanic activity, evolutionary changes in dental morphology of the Canidae species present in North America, or a periodicity of extinctions called van der Hammen cycles.
Amphimachairodus is an extinct genus of large machairodonts. It is also a member of the tribe Homotherini within Machairodontinae and is most closely related to such species as Xenosmilus, Homotherium itself, and Nimravides. It inhabited Eurasia, Northern Africa and North America during the late Miocene epoch.
Diegoaelurus is an extinct genus of placental mammals from extinct the subfamily Machaeroidinae within extinct family Oxyaenidae. This genus contains only one species Diegoaelurus vanvalkenburghae, which was found in the Santiago Formation in California. This mammal lived during the Uintan stage of the Middle Eocene Epoch around 46.2 to 39.7 million years ago.
Taowu is an extinct genus of machairodonts, a type of saber-toothed cat. It lived during the Early Pleistocene about 2.5 million years ago in East Asia. So far, only one skull is known, found in northern China. Based on this, a relatively small representative of the saber-toothed cats can be reconstructed, which only reached the size of a present-day leopard. In its dentition characteristics, it mediates between phylogenetic older forms such as Amphimachairodus and younger members such as Homotherium. The genus was scientifically described in 2022, but the find material was recovered as early as the 1930s.
Pangurban is an extinct genus of the family Nimravidae, endemic to North America during the Eocene epoch. It contains a single species, Pangurban egiae. Occurring several million years before other named nimravids in North America, the discovery of this species suggests that hypercarnivores evolved and spread quickly after the warm middle Eocene.
