Posted on 22 May 2014.
12,000-Year-Old ‘Naia’ Sheds New Light on Land Migration
ABOVE VIDEO: In a submerged cave in Yucatan, divers found
the near-intact skeleton of a delicately built teenage girl, who
died more than 12,000 years ago after she fell into a sinkhole
from which there was no way out.
She was found in the depths of planet Earth.
And she’s the oldest human skeleton ever found in North America, discovered by a team of international scientists in an underwater Yucatán Peninsula cave.
DNA from the skeleton shows similarities to modern Native Americans, while her skull structure matches those of Paleoamericans that came across the Bering land bridge.
In short, she may be the ‘missing link’ to the origins of the first Americans on the continent.
Named “Naia”, the teenager fell to her untimely and tragic death in a large pit called Hoyo Negro, meaning “black hole” in Spanish.
The divers found her on a ledge, her skull at rest on an arm bone. Ribs and a broken pelvis lay nearby. She was only a young teen when she wandered into the cave on the Yucatan Peninsula, and in the darkness she must not have seen the enormous pit looming in front of her.
More than 12,000 years later, in 2007, after the seas had risen and the cave system had filled with water, her skull — upside down, teeth remarkably intact — caught the eye of a man in scuba gear.
Patricia Beddows, a cave-diving researcher from Northwestern University, said the find is remarkable: “The preservation of all the bones in this deep water-filled cave is amazing– the bones are beautifully laid out.”
“The girl’s skeleton is exceptionally complete because of the environment in which she died — she ended up in the right water and in a quiet place without any soil. Her pristine preservation enabled our team to extract enough DNA to determine her shared genetic code with modern Native Americans,” she added.
The skeleton, which is now covered in water, is estimated to be between 12,000 and 13,000 years old, suggesting Naia lived in the late Pleistocene or last ice age.
She measured 4’ 10” tall and was delicately built. Slender and bucktoothed, her estimated age of death was 15 or 16 years old, based on the development of her teeth.
She lies in a collapsed chamber together with the remains of 26 other large mammals, including a saber-toothed tiger, 600 yards from the nearest sinkhole. Most of these ancient
mammals became extinct around 13,000 years ago.
“Naia, and the other animals, would have slipped through a hidden sink hole and fallen 100 feet into a shallow pool and trapped,” said paleontologist James Chatters of Applied Paleoscience in Bothell, Washington, who led the study, published May 15 in Science.
“There would have been no way out.” The broken pelvis of Naia’s otherwise near-perfect skeleton is likely a result of the accidental fall, he says.
Analysis of the remains in situ, most of which are still lying in the submerged cave where they were found, suggests that modern Native Americans are the descendants of the earliest Paleoamericans, who migrated from Siberia towards the end of the last glacial period. An alternative theory held instead that a mysterious, more recent influx had brought in new populations from Eastern Asia.
The near-complete human skeleton, which has an intact cranium and some of the oldest preserved DNA to date, was found lying 130 feet below sea level near a variety of extinct animals, including an elephant-like creature and relatives of the mastodon. Those remains helped scientists establish the age of the skeleton.
In order to assess the age of the skeleton, the team analyzed tooth enamel and seeds dropped by bats using radiocarbon dating and calcite deposits found on the bones using the uranium-thorium method.
They used similar methodology to date the remains of a variety of mastodon relatives found near the skeleton, which were found to be around 40,000 years old. The more than 26 large mammals found at the site included saber-toothed cats and giant ground sloths, which were largely extinct in North America 13,000 years ago.
Naia’s age was further supported by evidence of rising sea levels, which were as much as 360 feet lower during the last ice age than they are today.
Naia’s mitochondrial DNA reveals genetic signatures in common with modern Native Americans, despite her very different skull shape.
“You can never exclude that Native Americans have more than one group of ancestors,” says Chatters. But his team’s data, he points out, are consistent with the idea that Native Americans evolved from Siberian ancestors.
“It helps support the consensus view, from archaeological, genetic and linguistic evidence, that the Americas were initially peopled 15,000–20,000 years ago from Siberia,” says human geneticist Chris Tyler-Smith.
According to this widely held theory, the Americas were populated by Siberian ancestors who crossed the Bering land bridge that back then linked Eurasia and Alaska. The migration is thought to have started during the Pleistocene ice age– which ended around 14,000 years ago– and continued over the next several thousand years as these populations moved south.
Yet researchers have puzzled over why the more-than-10,000-year-old Paleoamerican skulls unearthed so far have such different morphology from those in more recent finds and from modern Native Americans.
Scientists wondered whether other Native American ancestors had arrived in a later migration. The new DNA results indicate that the very different skulls of modern Native Americans have evolved on North American soil.
Paleoamerican remains are few and far between, because the nomadic tribes did not always build tombs for their dead. The oldest and first full skeleton to be found, it’s the first major set of remains unearthed so far south.
~Via Science, Nature, IBT,
and Nature Newstream
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