Ancient infant skull yields insights into human-ape lineage

Researchers believe Alesi, an exquisitely preserved infant ape skull, belongs to Nyanzapithecus alesi, the earliest human-ape ancestor. Photo by Fred Spoor/MPG

Aug. 10 (UPI) — Researchers believe a 13 million-year-old skull recovered in Kenya belongs to the earliest common ancestor of humans and all living apes.

Paleontologists have made great strides in detailing the evolution of humans since they first diverged from apes some 7 million years ago. Less is known about human and ape ancestors living before 10 million years ago.

The newly discovered skull may offer some answers. Most importantly, the discovery confirms the earliest ape and human relative originated in Africa.

The skull was found among ancient rock layers located in Napudet, an area west of Lake Turkana in northern Kenya’s Rift Valley.

“The Napudet locality offers us a rare glimpse of an African landscape 13 million years ago,” Craig S. Feibel, a paleontologist at Rutgers University-New Brunswick, said in a news release. “A nearby volcano buried the forest where the baby ape lived, preserving the fossil and countless trees. It also provided us with the critical volcanic minerals by which we were able to date the fossil.”

The newly unearthed skull belonged to an infant ape. It was remarkably preserved. Three-dimensional X-ray imaging showcased the skull cavity and inner ears, as well as adult teeth yet to erupt.

“The quality of our images was so good that we could establish from the teeth that the infant was about 1 year and 4 months old when it died,” Paul Tafforeau, a researcher with the European Synchrotron Radiation Facility, said in a press release.

Analysis of the infant’s teeth suggests the ape belongs to a new species, Nyanzapithecus alesi.

Previous Nyanzapithecus species have only been identified by their teeth, and scientists haven’t been able to agree on whether the species were indeed apes.

The new species’ fully developed bony ear tubes confirms its place at the base of the ape lineage.

Further analysis of the ape skull suggests the new species looked similar to a gibbon with a small head and snout, but likely moved more cautiously through the trees.

Nyanzapithecus alesi was part of a group of primates that existed in Africa for over 10 million years,” said Isaiah Nengo, researcher at the Max PlanckSociety. “What the discovery of Alesi shows is that this group was close to the origin of living apes and humans and that this origin was African.”

Researchers detailed their discovery this week in the journal Nature.


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