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Photos and captions courtesy of the National Geographic Society. Sounds courtesy of www.freesound.com ('underwater' list).

Naia and the underwater discoveries at Hoyo Negro.


Underwater skeleton gives common ancestor to first Americans and Native Americans today

by Will Schutt and Farahnaz Mohammed
June 11, 2014


A diver in Hoyo Negro.

Photo by Daniel Riordan Araujo, used courtesy of the National Geographic Society.

A diver in Hoyo Negro shines her light on underwater bones.

NAIA_Info

Will Schutt and Farahnaz Mohammed/MEDILL

Recent discoveries at Ancient American sites.

A unique discovery.

These three little words mark the dreams and aspirations of any scientist - to find, notice and share something that no one else has revealed.

And that's what happened at Hoyo Negro, an underwater cave system in Mexico's Yucatan Peninsula.

An exploratory team found the remains of a skeleton there in a deep, underwater pit. The above ground science team, led by Mexico's National Institute of Anthropology and History (the INA) included American and Canadian scientists. The skeleton was of a teenage girl, named Naia by the team, who died more than 12,000 years old.

“What we're looking at with Naia is basically the full skeleton. All of the major bones are present...interestingly enough, the skeleton of Naia was actually found within three different places within the site. It's a feature of her having fallen down this pit. So she was walking through an air filled cave, and took a misstep, and fell over 100 feet down onto some rocks,” said project researcher and diver Patricia Beddows, a geologist with Northwestern University's Department of Earth and Planetary Sciences.

Scientists speculate she was looking for fresh water in an era when water levels were much lower.

The significance of Naia’s skeleton reaches far beyond her times. Naia's mitochondrial DNA shows a shared haplogroup (a genetic marker found in groups with a common ancestor) that today only occurs in Native Americans, providing a potential evolutionary basis for the development of modern tribal peoples from the hunter-gatherers who crossed the Bering Strait land bridge about 17,000 to 26,000 years ago. During the last ice age, ocean levels opened the land bridge between Siberia and Alaska. The findings were published May 16th in the journal Science.

However, modern Native Americans do not look like the Paleoamericans. They have different bone and facial structures. This has led to doubts in the link. Could changes in bone structure have been driven by evolutionary change? Or were the Paleoamericans replaced by another set of people after their arrival? Naia’s skeleton offers clues. Thanks to the quality of her preservation, scientists have been able to determine that she has both the bone structure and genetic signature of the Paleoamericans as well as DNA that links her to modern Native Americans. The clues suggest that the facial changes evolved once Paleoamericans migrated here.

Dominique Rissolo, executive director at the Waitt Institute explained the significance of the discovery of both the site and the skeleton. “It's really a once in a lifetime opportunity to be able to work at a site like Hoyo Negro,” said Rissolo. “We chance upon these sites so rarely...every site is so important to tell us about the early Paleoamericans.”

Alex Alvarez, a trained civil engineer turned cave diver, was the first to discover Hoyo Negro and the first to lay eyes on the skeleton.

Alvarez' first contact with Hoyo Negro came on Mother's Day, May 10th, 2007.

With some of his diving associates, he had been exploring a series of cenotes for several years. The project was exploratory in nature, with the divers mapping the cave system.

“My role in this dive was going first, scouting the cave,” said Alvarez. “When suddenly I saw no more refraction of my light from the walls of the tunnel. My heart started beating rapidly when I realized I was suddenly on the edge of a deep pit experiencing only darkness...we estimated it to be a bell shape with about 30 meters in diameter at 12 meters deep, opening to a 60 meter diameter at 60 meters depth. We named it “Hoyo Negro” (The Black Hole).

“Weeks after we came back with the proper gases to allow us to dive deeper into the pit. Once at depth we began finding groups of big bones. We were amazed and I realized we had discovered something big. As we continued looking around, I saw a human skull upside down resting on a humerus bone. I signaled Beto and Franco to show them what I had found. The three of us hovered over the skull, not believing what we saw. It blew our minds.”

It was Naia.

After the discovery, however, the site has been threatened by the increasing presence of unauthorized divers.

“Over the years of this project, the site has become increasingly known to cave divers, and it has even happened to us that during science dives, we have had the misfortune of having other people come into the site who have entered the cave system, which is now flooded, from other sinkholes, other cenotes, and found their way in,” said Beddows. “In that particular case when we were actually doing some science and ran into these two divers, we managed to literally push them back, and to discuss the fact that they were illegally entering a nationally Mexican protected archaeological site.”

Mexico's National Institute of Anthropology and History's mandate requires the find to be studied in situ as much as possible, so most of Naia and the other findings are still buried underwater. However, some parts of both Naia and the accompanying fossils have been brought out for dating and study. According to Rissolo, “the bones that were recovered are in the National Institute for Anthropology and History in Mexico in Campeche.”

Support was provided to this project by the National Geographic Society.