Evolution What the Fossils Say and Why it Matters

362 Evolution? The Fossils Say YES!

Galago

Tarsier

Orangutan

Gorilla

Chimpanzee Human

Primates

Lemur

New World MonkeyGibbon

Old World Monkey

Anthropoidea

Prosimians

FIGURE 15.4. Family tree of the major groups of living primates, showing the close relationships between the
great apes and humans and the more distant relationships of the Old World monkeys, New World monkeys,
and lemurs, lorises, and bush babies.

collections of their jaws and teeth are now stored in museums around the world. But as
world climate became cooler and drier in the Oligocene and the forests vanished, primates
became scarce, too. They vanished from North America and Europe, where they had once
flourished, and became restricted to Southeast Asia and Africa. During the Oligocene, one
group of primates, the Platyrrhini or New World monkeys, managed to make the crossing
of the South Atlantic, where they radiated into the great diversity of prehensile-tailed mon-
keys including spider monkeys, colobuses, and howler monkeys, marmosets, and the like.
Most primate evolution was confined to Africa, where the Old World monkeys (baboons,
macaques, rhesus monkeys, and their relatives) flourished, alongside the earliest members
of the ape lineage (Aegyptopithecus, Propliopithecus, Apidium, among others), which are docu-
mented from the Oligocene Fayûm beds of Egypt.