Plesiadapiformes

Plesiadapiformes ("Adapid-like" or "near Adapiformes") is an extinct basal pan-primates group, as sister to the rest of the pan-primates. The pan-primates together with the Dermoptera form the Primatomorpha. Purgatorius may not be a primate as an extinct sister to the rest of the Dermoptera or a separate, more basal stem pan-primate branch. Even with Purgatorius removed, the crown primates may even have emerged in this group. left|thumb|The plesiadapiform Plesiadapis|Plesiadapis cookei (right), compared to [[Notharctus tenebrosus (left), an early crown primate. Both come from Eocene Wyoming, though the former is slightly geologically older.]] Plesiadapiformes first appear in the fossil record between 65 and 55 million years ago, although many were extinct by the beginning of the Eocene. They may be the earliest known mammals to have finger nails in place of claws. In 1990, K.C. Beard attempted to link the Plesiadapiformes with the order Dermoptera. They proposed that paromomyid Phenacolemur had digital proportions of the fossil indicated gliding habits similar to that of colugos.

In the following simplified cladogram, the crown primates are classified as highly derived Plesiadapiformes, possibly as sister of the Plesiadapoidea. The crown primates are cladistically granted here into the Plesiadapiformes, and "Plesiadapiformes" become a junior synonym of the primates. With this tree, the Plesiadapiformes are not literally extinct (in the sense of having no surviving descendants). The crown primates are also called "Euprimates" in this context.