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Temporal range: MiocenePliocene
Thylacosmilus Atrox.jpg
Thylacosmilus atrox
Field Museum of Natural History
Scientific classification

Riggs, 1933

Thylacosmilus is a extinct genus of carnivorous sparassodont.[1] found as fossils in deposits dated from about 10 million to 3 million years ago (late Miocene to late Pliocene epoch) in Argentina, South America.

Thylacosmilus was sabre-toothed and was about as large as a modern jaguar. To a remarkable degree, Thylacosmilus paralleled the evolution of felid sabre-toothed cats like Smilodon. Its canine teeth were long and powerfully developed; they were used for stabbing prey. Its killing method was to hold its prey, and make deep bites into the soft tissue driven by powerful neck muscles.[2][3] The canine teeth were protected by a well-developed flange, or projecting edge, in the chin region of the lower jaw. The canines continued to grow during adult life, which they do not in marsupials or placental mammals.[4]

Thylacosmilus died out during the late Pliocene, whereas saber-toothed cats did not get to South America until the middle Pleistocene epoch.[5][6] As a result, the last appearance of Thylacosmilus is separated from the first appearance of Smilodon by over one and a half million years.

References[change | change source]

  1. The Sparassodonta were actually not marsupials, but a sister group which used to be described as marsupials.
  2. Hogenboom, M. (2013). "Sabretooth killing power depended on thick neck". BBC. Retrieved 2013-08-03.
  3. Wroe, S.; et al. (2013). "Comparative biomechanical modeling of metatherian and placental saber-tooths: a different kind of bite for an extreme pouched predator". PLoS ONE. 8 (6). doi:10.1371/journal.pone.0066888.
  4. Sparassodonts did not have the regular two-stage growth pattern of modern mammals.
  5. see Great American Interchange.
  6. Prevosti, Francisco J; Forasiepi, Analia & Zimicz, Natalia 2013. The evolution of the Cenozoic terrestrial mammalian predator guild in South America: competition or replacement?. Journal of Mammalian Evolution 20: 3–21. [1]