Figure 4.

Le Gros Clark’s conception of primate evolution as a series of grades, including a monkey grade, culminating in humans, based on Le Gros Clark [Le Gros Clark 1959]. This older view stands in contrast to the modern conception of primate evolution as being treelike, and in which Old World monkeys (cercopithecoids) are understood to be more closely related to humans than are New World monkeys (platyrrhines). Note that tree shrews are no longer considered primates (although they are close relatives), and that none of the living insectivore species are considered close relatives or primates.