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Creodonta

teeth, modern and true

CREODONTA, clan'ta, an extinct suborder of the carnivora (q.v.), distinguished by many primitive characters, and especially by the fact that the scaphoid and lunar bones of the wrist are separate instead of united into a single bone as in modern carnivora. In all modern land carnivores the last premolar tooth in the upper jaw and first true molar in the lower jaw are enlarged and pe culiarly adapted to cutting flesh (hence called "carnassials"), working against each other like a pair of shears. This is also the case with one group of the Creodonta, from which the modern carnivore are descended. But in most creo donts there is no specialized camassial, or it is developed from other teeth; these groups evolved on lines similar to the true carnivora, but have left no descendants. One group, the arctocyons, resembled the bears, with omnivo rous teeth, plantigrade feet, and large com pressed claws. Another group (Mcsonyx, Poch yerna, etc.) resembled rather the hyenas, with large strong teeth fitted for bone-crushing and digitigrade feet. Others had the teeth more

especially adapted to cutting flesh, the first upper and second lower molar being developed into carnassials in Oxyama and Patriofelis, the second upper and third lower molar in Hyeno don. Besides these larger forms from the size of a polar hear to that of a prairie wolf, there was a great variety of smaller creodonts, some more or less transitional to the primates, others to the insectivores. The early creodonts ap pear to represent most nearly the central stock from which most, if not all, of the modern mammals are descended (see CONDYLARTHRA) Creodonts were the dominant carnivore of the Eocene epoch, and a few survived into the Oligocene, when their place was taken by the true carnivore of more modern type. The evolution in the creodonts and true carnivores of carnassials of remarkably form, out of different pairs of teeth originally much less alike, is an excellent instance of "convergence" in evolution.