Oldest ape fossils hold clues to evolution

By AAP with Amy Middleton 16 May 2013
Reading Time: 2 Minutes Print this page
The earliest evidence of apes and monkeys co-existing has been uncovered in Tanzania.

25-MILLION-YEAR-OLD APE AND monkey fossils uncovered in Tanzania are the earliest evidence of these species co-existing, say researchers from Australia and the USA.

Scientists had previously predicted that apes and monkeys split from a common primate ancestor about 25–30 million years ago, however before now, the oldest known fossils were around 20 million years old.

“These discoveries suggest that the members of the major primate groups that today include apes and Old World monkeys were sharing the planet millions of years earlier than previously documented,” says study co-author Nancy Stevens of Ohio University in the United States.

Shifts in African landscape a factor in human evolution?

Australian scientists were among the international research team studying the skull fragments, which were discovered in 2011 and 2012.

The researchers say the findings, published today in the journal Nature, suggest that the early split between apes and monkeys may have been linked to a change in the African landscape.

“These fossils are associated with a major, previously unrecognised period of tectonic activity and landscape change in this part of Africa,” says co-author Dr Eric Roberts, from James Cook University in Queensland.

“It is possible that there is a link between the tectonic landscape changes that we have documented at this time, and the first appearance of apes and Old World monkeys.”

Old World monkeys such as baboons and macaques are found in Africa and Asia today, and are a distinct group from American (or New World) monkeys, such as marmosets and spider monkeys.

The jaw bone of a 25-million-year-old ape uncovered recently in Tanzania.

Earliest evidence of monkeys and apes

The skull fragments, uncovered in the Rukwa Rift Basin of Tanzania, belonged to a previously unknown monkey named Nsungwepithecus gunnelli, and an ape dubbed Rukwapithecus fleaglei.

From the ape, researchers unearthed a lower jawbone with several teeth, and from the monkey, a smaller piece of jawbone holding just one tooth.

All monkeys are members of the primate animal family, as are apes, such as gorillas, chimpanzees and humans.