Mesozoic: only when dinosaurs go extinct does the field go wide open. Cenozoic: first epoch is paleocene (65. 5-55. 8 mya, plesiadapiforms- early primate-like mammals. Evolution does not change all features of a species at the same time; pieces change at different times. If we have 10 features of primates, we would not expect to see all of these features in the earliest primates. Diastema: second epoch is eocene (55. 8-33. 9 mya, we see first fossils of animals that are truly primates, adapids and omomyids. Forward facing eyes: somewhere in the early eocene the primate story begins, at this point, the land masses are still connected. Why we find these fossils all over the world. Why and how did early primates evolve: 1. Nocturnal visual predation: primates are evolved to be active at night insect hunters, primates have stereoscopic vision, grasping hands, many other arboreal species, like squirrels, do not, nocturnal insect-hunting is common in small-bodied primates today, 2.