Plesiadapiformes


Plesiadapiformes is an order of Primatomorpha. While none of the groups normally directly assigned to this group survived, the group appears actually not to be literally extinct as the remaining primates appear to be derived Plesiadapiformes, as sister of e.g. the Carpolestidae. The term Plesiadapiformes may still be used for all primates which are not crown primates, but this usage is obviously paraphyletic. When the crown primates are cladistically granted, it becomes an obsolete junior synonym to primates. Purgatorius is believed to be a basal Plesiadapiformes.
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 have been the first 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 found highly derived Plesiadapiformes, possibly as sister of the Carpolestidae. The crown primates are cladistically granted here into the Plesiadapiformes, and the 'plesiadapiformes' become a junior synonym of the primates. With this tree, the plesiadapiformes are not literally extinct. The crown primates are also called "Euprimates" in this context.
In 2018, the plesiadapiform were proposed to be more related to Dermoptera, or roughly corresponding to Primatomorpha with both Dermoptera and the primates emerging within this group.
One possible classification table of plesiadapiform families is listed below.