Jaw bone of a gazelle from Jebel Irhoud, Morocco. The site contains the oldest-known skeletons of modern humans. UC Davis anthropologist Teresa Steele studied animal bones from the site, showing that our ancestors ate lots of gazelle and other game as well as ostrich eggs. Photo: Teresa Steele/UC Davis

The narrative of humanity’s beginnings came from a series of primates that gradually grew bigger brains in the crucible of East Africa over the course of millions of years, gradually resulting in a smarter species that developed tools and spread out across the globe. For decades, the first Homo sapiens to emerge from this “cradle” of humanity were thought to appear about 200,000 years ago.

But now a new dating technique applied to a deposit of fossils in Morocco may push the history of Homo sapiens back 100,000 years farther into the past, according to new studies in the journal Nature.

The site of Jebel Irhoud was well known since the 1960s for its hominid fossils and stone artifacts. The latest excavation project which began in 2004 turned up 16 new Homo sapiens fossil that were parts of the skull, teeth and long bones of five or more individuals.

But it was the technique of thermoluminescence of flint artifacts which were deposited in the soil alongside the fossils which came up with the age estimate of 300,000 years. (Analysis of the animal fossils, including rodent remains in the same strata indicated an estimate of 337,000 to 374,000 years old, as well).

The new testing method bucks previous dating which had placed a mandible found at the site in the 1960s at 160,000 years old, based on an electron-spin resonance dating method.

The fossils show skeletal remains that had similar structure to current-day humans – but had some differences, they report.

“Our findings suggest that modern human facial morphology was established early on in the history of our species, and that brain shape, and possibly brain function, evolved within the Homo sapiens lineage,” said Philipp Gunz, one of the authors, from the Max Planck Institute for Evolutionary Anthropology in Germany.

The oldest Homo sapiens found previous to the Moroccan finds were 195,000 years old, from Omo Kibish, Ethiopia.