Miacis is an extinct genus of mammals that appeared in the late Paleocene (ca. 60-55 million years ago) and are mammals of the family Miacidae, superfamily Miacoidea. They are representative of the group of early carnivores that were the ancestors of modern carnivores, ie., of the Order Carnivora; but only the species Miacis cognitus is a true carnivoran. Thus, Miacis may be considered the genus of carnivorous mammals that gave rise to all modern Carnivora. Miacis were five-clawed, about the size of a weasel (~30 cm), and lived on the North American and European continents. They retain some of the primitive characteristics that were present in the sister order of Carnivora of the same period known as the Creodonta, such as low skulls, long slender bodies, long tails, and short legs. It retains the same number of teeth, 44, although some reductions in this number were apparently in progress and some of the teeth are reduced in size. The hind limbs were longer than the forelimbs, the pelvis was very doglike in form and structure, and some specialized traits are present in the vertebrae. It had retractable claws, agile joints for climbing, and binocular vision. Miacis and related forms had brains that were relatively larger than those of the creodonts, and the increase in brain size as compared with body size probably reflects an increase in intelligence. Like many other early carnivorans, it was well suited for an arboreal climbing lifestyle with needle sharp claws, and had limbs and joints that resemble those of modern carnivorans. Miacis was probably a very agile forest dweller that preyed upon smaller animals, such as small mammals, reptiles, and birds, and might have also have eaten eggs and fruits, making Miacis an omnivore.
Referral of Miacis jepseni Guthrie to Oodectes Wortman, and an assessment of phylogenetic relationships among early Eocene Miacidae (Mammalia: Carnivora)
Nov 01, 1997; ABSTRACT-A phylogenetic analysis was conducted to address evolutionary relationships among the earliest members of the Miacidae...