Fossil shows modern humans left Africa earlier than thought

Fossil shows modern humans left Africa earlier than thought

Context

Scientists have announced the discovery of a fossilised human jawbone in a collapsed cave in Israel that they said is between 1,77,000 and 1,94,000 years old

Jawbone found in Misliya Cave on the western slopes of Mount Carmel in Israel

If confirmed, the find may rewrite the early migration story of our species, pushing back by about 50,000 years the time that Homo sapiens first ventured out of Africa.

Earlier discoveries

Previous discoveries in Israel had convinced some anthropologists that modern humans began leaving Africa between 90,000 and 120,000 years ago. But the recently dated jawbone is unravelling that narrative.

Modern humans moved out of Africa far earlier

The upper jawbone — which includes seven intact teeth and one broken incisor, and was described in a paper in the journal Science — provides fossil evidence that lends support to genetic studies that have suggested modern humans moved from Africa far earlier than had been suspected.

Early modern humans different than modern humans

“Early modern humans in many respects were not so modern,” said Jean-Jacques Hublin, director of the department of human evolution at the Max Planck Institute for Evolutionary Anthropology in Germany.

No conclusion

• Mr. Hublin said that by concluding the jawbone came from a “modern human”, the authors were simply saying that the ancient person was morphologically more closely related to us than to Neanderthals
• That does not mean that this person contributed to the DNA of anyone living today, he added. It is possible that the jawbone belonged to a previously unknown population of Homo sapiens that departed Africa and then died off.

Backdrop

• The upper jawbone, or maxilla, was found by a team led by Israel Hershkovitz, a palaeoanthropologist at Tel Aviv University and lead author of the new paper, while excavating the Misliya Cave on the western slopes of Mount Carmel in Israel.
• The team had long known that ancient people lived in the Misliya Cave, which is a rock shelter with an overhanging ceiling carved into a limestone cliff
• By dating burned flint flakes found at the site, archaeologists had determined that it was occupied 2,50,000 to 1,60,000 years ago, during an era known as the Early Middle Palaeolithic.

Base camp

• Evidence, including bedding, showed that the people who lived there used it as a base camp.
• The jaw bone was studied at a palaeontology lab run by Gerhard W. Weber, a palaeoanthropologist at the University of Vienna.
• There scientists were able to assess whether the bone belonged to a modern human or a Neanderthal, thought to have also occupied the region during that time period.

3D replica

Using high resolution micro-CT scanning, Mr. Weber created a 3D replica of the upper left maxilla that allowed him to investigate its surface and, virtually, to remove enamel from the teeth.

Tests

He then performed a morphological and metric test that compared the Misliya fossil with about 30 other specimens, including fossils of Neanderthals, Homo erectus , more recent Homo sapiens , and other hominins who lived in the Middle Pleistocene in Asia, Africa Europe and North America.

Dating

• The team dated the tooth dentin and enamel, the sediment stuck to the upper jaw, and tools found near the fossil.
• Together, the techniques put the jawbone at between 177,000 and 194,000 years old, in line with what was already known about the period during which the cave was inhabited.
• This thing is as old as we thought it was, and it was probably the earliest Homo sapien out of Africa ever found
• The shape of the second molar, the two premolars and the whole maxilla are very modern