Final answer:
Proto-primates are believed to have evolved about 65 MYA during the Paleocene epoch, and the documented presence of the primative primate called Purgatorius unio around this time signals the emergence of early primates. Plesiadapis is another significant proto-primate that lived around the same period. The Eocene epoch witnessed further evolutionary advancements in primate development.
Step-by-step explanation:
The earliest proto-primates are believed to have evolved around 65 million years ago (MYA), during the Paleocene epoch, just after the dinosaurs became extinct. The oldest known primate-like mammal with a substantial fossil record is Plesiadapis, although its classification as a proto-primate is sometimes debated among researchers. Genetic evidence suggests that primates diverged from other mammals about 85 MYA, but it is the presence of a creature known as Purgatorius unio from the earliest part of the Paleocene, with its 'Bugs Bunny teeth', that signals the emergence of definitive primate characteristics. During the Eocene epoch, which began around 54 MYA, primates began to show evolutionary changes such as larger brains and eyes, and smaller muzzles, paving the way for the later appearance of true primates resembling today's prosimians, such as lemurs. By the end of the Eocene, many of the early prosimian species had gone extinct, likely due to cooler temperatures or competition from the first monkeys.