Charles Q. Choi writes: The most complete extinct-ape skull ever found reveals what the last common ancestor of all living apes and humans might have looked like, according to a new study.

The 13-million-year-old infant skull, which its discoverers nicknamed “Alesi,” was unearthed in Kenya in 2014. It likely belonged to a fruit-eating, slow-climbing primate that resembled a baby gibbon, the researchers said.

Among the living primates, humans are most closely related to the apes, which include the lesser apes (gibbons) and the great apes (chimpanzees, gorillas and orangutans). These so-called hominoids — that is, the gibbons, great apes and humans — emerged and diversified during the Miocene epoch, approximately 23 million to 5 million years ago. (The last common ancestor that humans had with chimpanzees lived about 6 million to 7 million years ago.)

Much remains unknown about the common ancestors of living apes and humans from the critical time when these branches diverged. Fossil evidence from this part of the primate family tree is scarce, and consists mostly of isolated teeth and broken jaw fragments. As such, researchers were not sure what the last common ancestors of living apes and humans might have looked like, and even whether they originated in Africa or Eurasia. [Continue reading…]