17-Million-Year-Old Ape Jaw From Egypt Rethinks Ape Origins

The takeaway: a flexible diet may have been this ape's key survival tool in a shifting climate.

Why does one jaw challenge the ape family tree?

For decades, scientists assumed early apes and their relatives lived mainly farther south in Africa. North African sites of the same age had yielded ancient monkeys, but never a confirmed ape. Younger ape fossils exist across Africa, Europe and Asia, yet their relationships and geographic origins remain contested.

"We spent five years searching for this kind of fossil because, when we look closely at the early ape family tree, it becomes clear that something is missing — and North Africa holds that missing piece," said Hesham Sallam, a paleontologist at Mansoura University and senior author of the study.

The team placed the species on the tree using Bayesian methods — statistical techniques that compare competing evolutionary scenarios and weigh how strongly the evidence supports each. They combined anatomy from living and extinct apes, genetic data from living species, and the geological ages of fossils to estimate when branches split.

The result: Masripithecus was more closely related to living apes than any known ape species from the Early Miocene of East Africa. Additional analyses of ancient animal distributions pointed to northern Africa and the Middle East as the most likely home of the common ancestor of all living apes, estimated to have lived during the Early Miocene, roughly 23 to 16 million years ago.

In short, the data move the ape cradle north.

How much does this change — and what doesn't it?

The stakes involve crown Hominoidea: the group containing the last common ancestor of all living apes — gibbons, orangutans, gorillas, chimpanzees and humans — plus its descendants. Humans emerged much later, and the researchers explicitly do not claim Masripithecus was a direct human ancestor, or even necessarily the direct ancestor of living apes. Its position on the tree simply marks where the broader lineage likely originated.

Erik Seiffert, a USC paleontologist and co-author, said the evidence overturned a belief he had held for decades: "For my entire career, I considered it probable that the common ancestor of all living apes lived in or around East Africa. But this new discovery, and our new and novel analyses of hominoid phylogeny and biogeography, now strongly challenge that idea. And, importantly, the likelihood of this scenario doesn't depend on Masripithecus — but it is very much consistent with it."

Geography may explain the region's role. As the African and Arabian plates drifted north toward their final collision with Asia, and sea levels rose and fell, land connections between Africa and Eurasia periodically opened, letting animals migrate. Northern Africa and the Middle East sat at that crossroads.

What comes next?

The limits are real. Only part of one jaw exists, leaving the animal's body size, posture and behavior unknown. More fossils from North Africa and the Middle East could reveal further species and clarify when the major ape branches diverged.

A single jaw, preserved for nearly 18 million years, is already rewriting where our lineage began.