Creodonta

Template:Taxobox begin Template:Taxobox image Template:Taxobox begin placement Template:Taxobox regnum entry Template:Taxobox phylum entry Template:Taxobox classis entry Template:Taxobox ordo entry
Template:Taxobox authority parens Template:Taxobox end placement Template:Taxobox section subdivision Hyaenodontidae
Oxyaenidae
Template:Taxobox end The creodonts are an extinct order of mammals that lived from the Paleocene to the Pliocene.

Evolution

They were previously considered ancestral to the carnivores, Carnivora, but are now considered to have shared a common ancestor further back. Some researchers argue that the creodonts themselves in fact represent a group of mammals of diverse biological ancestry in the mammal line that resemble one another via convergent evolution, rather than being the decendents of a common ancestor of all animals in the order. They were the dominant carnivorous mammal from 55 to 35 MYA, sharing with the Carnivora the carnassial shear, scissor teeth that evolved to slice meat and gave both orders the tools to dominate the niche.

Habitat

The creodonts ranged across North America, Eurasia and Africa, in forms that resemble those of modern carnivores. Amongst their number was Megistotherium, which some argue was the largest mammalian land predator of all time, the size of a bison and with a skull twice as big as a tiger's. Megistotherium may have rivaled Andrewsarchus mongoliensis in size. Their dominance over the early Carnivora, known as miacids, began to wane after 35 MYA. The creodonts survived until 8 million years ago; the last form, Dissopsalis, lived in Pakistan. It is not known exactly why the Creodonts were replaced by Carnivora. Their smaller brains and somewhat less energy-efficient locomotion, especially while running, may have given the Carnivora a subtle advantage that over millions of years allowed them to take over. The Carnivora also had a slightly different arrangement of teeth which may have made digestion more efficient and allowed the Carnivora to eat a wider variety of food. Bears, cats, mustelids, canids such as wolves and other Carnivora now occupy the former creodont niches.

References

The Velvet Claw, A Natural History of the Carnivores, David Macdonald, BBC Books, ISBN 0563208449