Amphicynodons

The earliest members of Ursidae belong to the extinct subfamily Amphicynodontinae, including Parictis (late Eocene to early middle Miocene, 38–18 Mya) and the slightly younger Allocyon (early Oligocene, 34–30 Mya), both from North America. These animals looked very different from today's bears, being small and raccoon-like in overall appearance, and diets perhaps more similar to that of a badger. Parictis does not appear in Eurasia and Africa until the Miocene.[8] It is unclear whether late-Eocene ursids were also present in Eurasia, although faunal exchange across the Bering land bridge may have been possible during a major sea level low stand as early as the late Eocene (about 37 Mya) and continuing into the early Oligocene.[9] European genera morphologically are very similar to Allocyon, and also the much younger American Kolponomos (about 18 Mya), are known from the Oligocene, including Amphicticeps and Amphicynodon. …show more content…
The subfamily also includes the younger genera Phoberocyon (20–15 Mya), and Plithocyon (15–7 Mya).

A Cephalogale-like species gave rise to the genus Ursavus during the early Oligocene (30–28 Mya); this genus proliferated into many species in Asia and is ancestral to all living bears. Species of Ursavus subsequently entered North America, together with Amphicynodon and Cephalogale, during the early Miocene (21–18 Mya).

Members of the living lineages of bears diverged from Ursavus between 15 and 20 Mya ago,[10][11] likely via the species Ursavus elmensis. Based on genetic and morphological data, the Ailuropodinae (pandas) were the first to diverge from other living bears about 19 Mya ago, although no fossils of this group have been found before about 5