Chapter 7: primate evolution: from early primates to hominoids. O dentition: the type, number, and arrangement of teeth. O arboreal quadrupeds: front and back limbs of the same length, grasping toes and fingers. O terrestrial quadrupeds: more adopted to speed, longer limbs, shorter fingers and toes. O vertical clingers and leapers: longer more powerful hind limbs. O paleocene epoch: the geological epoch 65 million to 55 million years ago. O plesiadapis: the most well known of the plesiadipiforms, possibly an archaic primate; squirrel like animal, large snout, incisors, nasal cavity, eye orbits (side of head), claws, no grasping hands/feet, not a primate! O eocene: a geological epoch 55 million to 34 million years ago during which the first definite primates appeared. O adapids: led to modern lemurs and lorises and the mommies led to tarsiers and anthropoids. O omomyids: larger brain, poster orbital closure around eyes, short face.