Fossils of earliest Old World monkeys unearthed. (Live Science)

Ancient teeth of old-world monkeys, which are most closely related to humans, have now been unearthed, fossils 3 million years older than previous remains found to date, researchers say.

The old-world monkeys are native to Africa and Asia today, and include many familiar primates, such as baboons and macaques. Unlike the new-world monkeys of the Americas, tails of old-world monkeys are never prehensile, or able to grasp things.

The modern old-world monkeys emerged during the Miocene epoch, which lasted about 5 million to 23 million years ago and saw the first appearance of wide expanses of grasslands. However, the monkeys' origins and the way they subsequently diversified remain uncertain, since there is a scarcity of fossil sites on land in Africa dating between 6 million and 15 million years old.

Read more: https://www.livescience.com/27980-earliest-old-world-monkeys.html