Saber-toothed cat
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The terms saber-toothed cat and saber-toothed tiger describe numerous species, mainly in the families Felidae, Hyaenodontidae, and Nimravidae, but also including two marsupial families, that lived during various parts of the Cenozoic and evolved their saber-toothed characteristics entirely independently. The saber-tooth morphology is an excellent example of convergent evolution as it occurred repeatedly and independently in at least four distinct mammalian groups.They are most known for having teeth, that were in some species up to 20 cm long and extended down from their mouth even when closed.
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[edit] Saber-tooth genera
The genera of sabre-toothed cats, along with the regions and time periods where they have been found, is summarized here:
| Genus Name | Number of Species | Times | Regions |
| Smilodon | 6 | 2.5 MYA to 8,000 YA | North America |
| Hoplophoneus | 5 | 33.7 MYA to 23.8 MYA | North and South America |
| Eusmilis | 3 | 30.5 MYA to 28 MYA | Europe, North America, South America |
| Dinictis | 4 | 40 MYA to 25 MYA | North America |
| Dinaelurus | 1 | ? | North America |
| Dinailurictis | 1 | ? | ? |
| Eofelis | 1 | ? | ? |
| Nimravidus (Nimravides) | 2 | ? | ? |
| Nimravus (Nimravinus) | 6 | 33.5 MYA to 20 MYA | Europe and North America |
| Nimraviscus | 1 | ? | ? |
| Pogonodon | 2 | 15 MYA to 6 MYA | Europe and North America |
| Quercylurus | 1 | ? | ? |
| Archaelurus | 1 | ? | ? |
| Aelurogale (Ailurictis) | 1 | ? | ? |
| Ictidailurus | 1 | ? | ? |
| Albanosmilus | 3 | 18 MYA to 3 MYA | Africa and Eurasia |
| Afrosmilus | 1 | 25 MYA to 10 MYA | Africa |
| Barbourofelis | 7 | 15 MYA to 3 MYA | Africa and Eurasia |
| Ginsburgsmilus | 1 | 23 MYA to 10 MYA | Africa |
| Prosansanosmilus | 2 | 18 MYA to 5 MYA | Africa and Eurasia |
| Sansanosmilus | 3 | 12 MYA to 3 MYA | Africa and Eurasia |
| Syrtosmilus | 1 | 23 MYA to 8 MYA | Africa |
| Vampyrictis | 1 | 15 MYA to 3 MYA | Africa and Eurasia |
| Vishnusmilus | 1 | ? | ? |
| Homotherium | 10 | 3 MYA to 10,000 YA | Europe and Asia |
| Miracinonyx | 2 | 3.2 MYA to 10,000 YA | North America |
| Thylacosmilus (marsupial) | 2 | 10 MYA to 1.8 MYA | South America |
| Metailurus | 9 | 15 MYA to 8 MYA | Eurasia |
| Adelphailurus | 1 | 23 MYA to 5 MYA | Kansas (North America) |
| Paramachairodus | 3 | 20-15 MYA to 9 MYA | Europe |
| Machairodus (Ancestral to Homotherium) | 18 | 15 MYA to 2 MYA | Africa, Europe, Asia, and North America |
| Megantereon | 8 | 3 MYA to 9,000 YA | Africa, Eurasia, and North America |
| Dinofelis | 6 | 5 MYA to 1.5 MYA | Africa, Eurasia, North America |
| Therailurus | 1 | 5 MYA to 2 MYA | Africa, Eurasia, North America |
| Pontosmilus | 4 | 20 MYA to 9 MYA | Eurasia |
| Proailurus | 2 | 30 MYA to 20 MYA | Europe, North America |
| Pseudaelurus | 1 | 20 MYA to 10 MYA | Europe, North America |
| Xenosmilus (1 specimen) | 1 | 1.7 MYA to 1 MYA | Central Florida (North America) |
| Stenailurus | 1 | (?) | (?) |
| Dinobastis | 1 | (?) | Asia |
| Epimachairodus | 1 | (?) | (?) |
| Miomachairodus | 1 | (?) | (?) |
| Hemimachairodus | 1 | (?) | (?) |
| Ischyrosmilus | 1 | (?) | (?) |
[edit] Saber-tooth evolutionary tree
All saber-tooth mammals lived between 9,000 and 33.7 million years ago, but the evolutionary lines that lead to the various saber-tooth genera started to diverge much earlier.
The lineage that led to Thylacosmilus was the first to split off, in the late Cretaceous. It is a marsupial, and thus more closely related to kangaroos and opossums than the felines. The creodonts diverged next, and then the nimravids, before the blossoming of the truly feline saber-tooths.
- Class Mammalia
- Subclass Marsupialia (diverged ? MYA, in the Cretaceous)
- Order Sparassodonta (an extinct group of marsupial carnivores)
- Family Borhyaenidae
- Family Thylacosmilidae
- Order Sparassodonta (an extinct group of marsupial carnivores)
- Subclass Placentalia
- Order Creodonta (diverged ? MYA, in the Paleocene)
- Family Hyaenodontidae
- Hyaenodon
- Boualitomus
- Laekitherium
- Metapterodon
- Triacodon
- Parvagula
- Family Hyaenodontidae
- Order Carnivora
- Family Nimravidae (diverged from the felioformes 48–55 MYA, in the late Eocene)
- Subfamily Nimravinae (Dinictis)
- Subfamily Hoplophoninae
- Subfamily Barbourofelinae
- Family Felidae (true cats)
- Subfamily Machairodontinae (diverged ? MYA, in the ?)
- Tribe Homotheriini
- Tribe Metailurini
- Tribe Smilodontini
- Subfamily Machairodontinae (diverged ? MYA, in the ?)
- Family Nimravidae (diverged from the felioformes 48–55 MYA, in the late Eocene)
- Order Creodonta (diverged ? MYA, in the Paleocene)
- Subclass Marsupialia (diverged ? MYA, in the Cretaceous)
