Plesiadapiforms
are organisms that may have been the first primates. This group of primates underwent an adaptive radiation which enable them to produce forms with very distinctive features including weird, multi-cusped incisors and a variety of very sepcialized lower premolars.
The first record of plesiadapiforms appeared just as the non-avian dinosaurs were about to be extinct 65 million years ago, near the inception of the Paleocene age. Some of these primates persisted well into the epoch of Eocene with the last of its species extincting around 37 million years ago.
