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 15 years old when she wandered into the cave, perhaps in search of water in an era when the Yucatan was parched.
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.
The divers gave the girl a name: Naia. Her remains may help determine the origins of the earliest Americans and finally solve the mystery of why they looked so dramatically different from the Native Americans of recent millenniums.
A paper published Thursday online in the journal Science argues that the discrepancy in appearance between the Paleoamericans and later Native Americans is most likely the result of recent, and relatively rapid, human evolution – and not the result of subsequent migrations of people into the Americas.
Tests on samples of mitochondrial DNA taken from Naia show that she has a genetic marker common today across the Americas, one that scientists say evolved in a prehistoric population that had been isolated for thousand of years in Beringia, the land mass between Alaska and Siberia that formed a bridge between the continents during the Ice Ages.
Thus, according to the new report, the Native Americans and the Paleoamericans are the same people; they just look different because of evolutionary changes.