Fossil Suggests Earliest Known Movement of Humans Out of Africa (#GotBitcoin?)
Ancient skull bone was overlooked for nearly 40 years. Fossil Suggests Earliest Known Movement of Humans Out of Africa (#GotBitcoin?)
An ancient skull bone unearthed in Greece, overlooked for decades in an Athens museum, may be the earliest known evidence of modern humans outside Africa, a new study says.
The cranium dates to more than 210,000 years ago, older than any other fossil of Homo sapiens known in Eurasia, according to a research team led by paleoanthropologist Katerina Harvati at Germany’s Eberhard Karls University of Tübingen. The researchers published their analysis of the Greek fossils Wednesday in the journal Nature.
The new finding suggests that our direct ancestors tried repeatedly to move into Europe and Asia, where other early human species already had settled, before finally securing a lasting homeland there, several experts in human origins said.
Modern humans did not replace Neanderthals across Europe until about 45,000 years ago.
“It is evidence that our species moved out of Africa several times and kept pushing the limits of our geographical abilities until we were successful,” said paleoanthropologist Eric Delson at Lehman College of the City University of New York, who wasn’t involved in the study. “Here, we have a population in Greece which probably was part of a failed dispersal.”
Until now, the earliest modern human fossil found outside Africa was a jawbone found in Misliya Cave on Mount Carmel in Israel that has been dated to between 177,000 and 194,000 years old.
The fossil cranium of Homo sapiens was among many skull fragments cemented together inside a block of breccia discovered by researchers in 1978 at a seaside cave in Southern Greece. However, it took almost 40 years for scientists to fully understand what time and geology had hidden inside the lump of sedimentary stone they found wedged near the ceiling of the Apidima Cave, as the cavern is called.
Initially, researchers had assumed the skull bones were most likely Neanderthal and were all of the same age.
Only recently did Dr. Harvati and her colleagues realize the stone contained fossil remains of two individuals who belonged to not one but two different human species, who had lived and died in the same place nearly 40,000 years apart.
And, to their surprise, the more anatomically modern one was the more ancient of the two.
The older skull, called Apidima 1, belonged to Homo sapiens and was at least 210,000 years old, the researchers said. The curve of its cranium is considered a uniquely modern trait.
The younger one, called Apidima 2, was Neanderthal, with a thick brow ridge, and dated to about 170,000 years ago. The stone matrix that cemented them together was about 150,000 years old.
“It is a fantastic coincidence that you have two skulls together 30 centimeters apart,” said Rainer Grün, geochronologist at Griffith University’s Australian Research Centre for Human Evolution, who calculated the age of the specimens.
“It is a wonder of nature.”
Previous efforts to determine the fossils’ age had been “inconclusive,” the researchers said. In the new study, Dr. Grün tested samples using a technique called laser ablation mass spectrometry that measures levels of uranium isotopes.
No one knows what happened to these early migrants, the researchers said. They could have retreated in the face of a cooling climate, followed a wandering herd into other territory, or been flooded out by rising seas. Some 200,000 years ago, the cave overlooked a dry plain. Today the cave site is accessible only by boat.
They may also have been displaced by the Neanderthals who settled in the same area, the researchers said.
In fact, it is possible the two species intermingled there and perhaps interbred.
“It is highly suggestive,” said Dr. Harvati. “There could have been contact between this population and Neanderthals.”
These prehistoric pioneers, though, likely left no descendants. So far, there are no fossil DNA samples to test. “They died out,” said Dr. Harvati. “We think these early migrants did not contribute genetically to modern Eurasian humans today.” Fossil Suggests Earliest Known, Fossil Suggests Earliest Known