Miacidae

Miacidae is an extinct family of early carnivorans that lived during the Paleocene to Eocene epochs, roughly 60 to 34 million years ago. In traditional classifications, Miacidae is placed within Carnivoraformes and is considered a stem group to the true Carnivora, comprising several genera with the type genus Miacis. The group is often described as a paraphyletic grade rather than a natural clade, with lineages giving rise to later carnivoran families such as Caniformia and Feliformia.

Miacids were small to medium-sized, with slender, elongated bodies and limbs adapted for a mix of terrestrial and arboreal locomotion. Their dentition shows a combination of sharp cusps and developed carnassial blades, indicating a predominantly carnivorous diet, though some taxa may have had omnivorous or insectivorous elements. The skull and teeth reflect a transitional stage between early carnivorous mammals and more specialized later carnivores.

The fossil record shows Miacids across a broad geographic range, with remains found in North America, Europe, and Asia, suggesting a widespread and successful group during their time. They are characterized as early, primitive carnivorans preceding the diversification of modern Carnivora. By the late Eocene, more derived carnivoran lineages evolved, and Miacidae declined, ultimately giving rise to the crown-group Carnivora. The best-known genus is Miacis, which illustrates the general morphology and lifestyle of these early carnivorans.