Saber-toothed cat

Saber-toothed cat or Sabre-toothed cat^[1] (see spelling differences) refers to the extinct subfamilies of Machairodontinae (Felidae), Barbourofelidae (Feliformia), and Nimravidae (Feliformia) as well as two families related to marsupials that were found worldwide from the Eocene Epoch to the end of the Pleistocene Epoch (42 mya—11,000 years ago), existing for approximately 42 million years.^[2][3][4] They are so called for their large, saber-like maxillary canine teeth, which extended from their mouths even when it was closed. Despite the name, not all animals known as saber-toothed cats were closely related to modern felines.

The Nimravidae are the oldest, entering the landscape around 42 mya and becoming extinct by 7.2 mya. Barbourofelidae entered around 16.9 mya and were extinct by 9 mya. These two would have shared some habitats.

Morphology

These subfamilies evolved their sabre-toothed characteristics entirely independently. They are most known for having maxillary canines which were, in some species, up to 50 cm(19.7 inches) long and extended down from the mouth even when the mouth was closed. Sabre-toothed cats were generally more robust than today's cats and were quite bear-like in build. They were believed to be excellent hunters and hunted animals such as sloths, mammoths, and other large prey. Evidence from the numbers found at La Brea Tar Pits suggests that Smilodon, like modern lions, was a social carnivore.^[5]

Saber-tooth genera

Saber-tooth evolutionary tree

All saber-tooth mammals lived between 33.7 million and 9,000 years ago, but the evolutionary lines that led to the various saber-tooth genera started to diverge much earlier. It is thus a polyphyletic grouping.

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 ?, in the Cretaceous)
    • Order †Sparassodonta (an extinct group of marsupial carnivores)
      • Family †Borhyaenidae
      • Family †Thylacosmilidae
        • †Patagosmilus
        • †Anachlysictis
        • †Thylacosmilus
  • Subclass Placentalia
    • Order †Creodonta (diverged ?, in the Paleocene)
      • Family †Hyaenodontidae
        • †Hyaenodon
        • †Boualitomus
        • †Laekitherium
        • †Metapterodon
        • †Triacodon
        • †Parvagula
        • †Machaeroides
    • Order Carnivora
      • Family †Nimravidae (diverged from the feliforms 48–55 Ma BP, in the late Eocene)
        • Subfamily †Nimravinae (Dinictis)
        • Subfamily †Hoplophoninae
      • Suborder Feliformia ('cat-like' carnivores)
        • Family †Barbourofelidae (sister taxa to Felidae)
        • Family Felidae (true cats)
          • Subfamily †Machairodontinae (diverged ?, in the ?)
            • Tribe †Homotheriini
              • †Homotherium
              • †Machairodus
              • †Xenosmilus
            • Tribe †Metailurini
              • †Dinofelis
              • †Metailurus
            • Tribe †Smilodontini
              • †Megantereon
              • †Paramachairodus
              • †Smilodon

Literature

• D. Mol / W. v. Logchem / K. v. Hooijdonk / R. Bakker: The Saber-Toothed Cat, DrukWare, Norg 2008, ISBN 978-90-78707-04-2

References

External links

• Extinct Cats Index
• Illinois State Museum: Saber-toothed Cats
• UC Berkeley Museum of Paleontology: Sabre-toothed Cats
• Prehistoric cats and prehistoric cat-like creatures