10,000-year-old skeleton challenges theory of how humans arrived in Americas

Study of human remains suggests two distinct populations were co-existing in central America 8,000 - 12,000 years ago

The discovery of a 10,000-year-old skeleton in an underwater cave in Mexico provides new evidence humans did not first arrive in the Americas as a single population as “traditional” theory holds, but came from various areas, researchers claim.

The well-preserved remains belonged to a 30-year-old Paleoindian woman and were found in a cave called Chan Hol near the city of Tulum on Mexico’s Yucatán Peninsula.

Researchers said the find suggests multiple groups of early settlers were arriving “from different geographical points of origin”.

The skeleton has been named Chan Hol 3 and scientists say the shape and structure of the skull is different to other skeletons found and which come from a similar time period, indicating at “least two morphologically different Paleoindian populations”.

Paleoindians were the first peoples to arrive, and subsequently inhabit, the Americas.

It is believed they journeyed across an ancient land bridge connecting Asia to North America, known as Beringia, during the last Ice Age more than 12,000 years ago, before migrating to the Patagonian region in South America.

Dr Silvia Gonzalez, a professor of quaternary geology and geoarchaeology at Liverpool John Moores University, and one of the study authors, told the PA news agency: “The new results are important because they question the ‘traditional model’ for the peopling of the Americas with one single and homogeneous Paleoindian population migrating very fast from Beringia to Patagonia after 12,000 years ago.

“Our results indicate that at least two morphologically different Paleoindian populations were coexisting in Mexico between 12,000 to 8,000 years ago, one in Central Mexico and the other in the Yucatan Peninsula.

Professor Silvia Gonzalez (left) and Dr Sam Rennie with the Chan Hol 3 skeleton found in an underwater cave near the eastern Mexico town of Tulum (PA)

The team, led by Professor Wolfgang Stinnesbeck, an earth scientist at Heidelberg University, dated the skeletal remains using mineral deposits called flowstone which covered some finger bones.

They believe Chan Hol 3 to be at least 9,900 years old, if not older.

Structural analysis revealed Chan Hol 3 had a round head with broad cheekbones and a flat forehead, resembling three other skulls from the Tulum caves.

But according to the researchers, her cranial characteristics are different to the long-headed Paleoindian skeletons found in the region.

Dr Gonzalez said: “The Tulum skeletons may indicate that either more than one group of humans originally reached the American continent from different geographical points of origin, or that there was sufficient time for a small group of early settlers living in isolation on the Yucatan Peninsula, to develop a different skull morphology.

“In either case, the early settlement history of the Americas appears to be more complicated and may date back thousands of years earlier than commonly believed, according to the new human morphology data.”

The findings are described in the journal PloS One.

Additional reporting by PA