Arctocyonidae

Arctocyonidae (from Greek arktos kyôn, "bear/dog-like") is an extinct family of unspecialized, primitive mammals with more than 20 genera. The family was most abundant during the Paleocene, but extant from the late Cretaceous to the early Eocene (66 to 50 million years ago). These animals are thought to be the ancestors of the orders Mesonychia and Cetartiodactyla, although some morphological studies have suggested that Arctocyonidae is a 'wastebasket' group for basal ungulates, and is in fact, polyphyletic

Characteristics

Arctocyonid skulls had large canines and relatively sharp teeth and were thus superficially similar to those of modern carnivores. However, arctocyanid teeth were not specialized for slicing meat; these animals were probably omnivorous and definitely the least herbivorous of the condylarths. Arctocyonid teeth show much individual variation and, because many members of this family are only known from fossil teeth, the taxonomy of the genera is highly unstable.