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Creodonts

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Creodonts

Creodonta
Temporal range: Late Paleocene to Late Miocene, 63.3–11.1Ma
Sarkastodon
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Infraclass: Eutheria
Superorder: Laurasiatheria
Order: Creodonta
(Cope, 1875)
Families

Hyaenodontidae
Oxyaenidae

Creodonta is an extinct order of mammals that lived from the Paleocene to the Miocene epochs. Creodonts shared a common ancestor with the Carnivora.

Creodonts were an important group of million years ago, and carnivorans now occupy their ecological niches.

Evolution and taxonomy

Creodonts were traditionally considered ancestors to Carnivora, but are now considered to have shared a common ancestor further back — possibly a million years ago.

Habitat

The creodonts ranged across wolves, and other Carnivora now occupy the former creodont niches.

Extinction

It is not known exactly why the creodonts were replaced by Carnivora. It may be because of their smaller brains and their locomotion, which was somewhat less energy-efficient (especially while running).[3] Their limb structure limited leg movement to a vertical plane, as in horses; they were unable to turn their wrists and forearms inward to trip, slash, or grab prey as modern carnivores can. Creodonts had to depend entirely on their jaws to capture prey, which may be why most creodonts had much larger heads than carnivores of the same body size. The creodont lumbosacral spine was not arranged as efficiently for running as in Carnivora. The arrangement of the teeth was also somewhat different. In the miacids (and so in the modern Carnivora), the last upper premolar and the first lower molar are the carnassials, allowing grinding teeth to be retained behind for feeding on non-meat foods (the Canidae are the closest modern analog to miacid dentition). In creodonts, the carnassials were further back—either the first upper and second lower molars, or the second upper and third lower molars. This committed them to eating meat almost exclusively. These limits may have created important disadvantages over millions of years.

In the most strictly carnivorous family of modern Carnivora, the Felidae, the second and third molars have disappeared completely, and the first upper molars behind the carnassials have become vestigial. Modern cats thus eat plant food only incidentally.

Footnotes

References

  • The Velvet Claw: A Natural History of the Carnivores, David Macdonald, BBC Books, ISBN 0-563-20844-9
  • David Lambert and the Diagram Group. The Field Guide to Prehistoric Life. New York: Facts on File Publications, 1985. ISBN 0-8160-1125-7
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