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Modern Human fossils in Ethiopia 33,000 years older than thought

The oldest proof of Homo Sapiens presence in Eastern Africa is older than previously thought. Fossils date back earlier than a volcanic eruption 233,000 years ago.

Ethiopia Omo Kibish human fossils
The Omo Kibish geological formation in Ethiopia, near the location where Homo sapiens fossils were discovered in the late 1960s, which have now been determined to be at least 233,000 years old | Celine Vidal via Reuters

The fossil bones were contained in sediments beneath ash that resulted from a volcanic eruption in Ethiopia roughly 233,000 years ago, with a 22,000-year margin of error. The previous estimated age was 197,000 years.

The Homo Sapiens fossils were discovered in Ethiopia in 1967. Called Omo I, they include a cranial vault, lower jaw, some vertebrae and parts of the arms and legs.

Results were published in the scientific publication Nature on January 12. Scientists said they used the thick layer of ash that contained the fossils.

They compared the ash geochemical composition with other volcanic remnants in the region and found a match with a volcanic rock during another eruption about 370 km (230 miles) away that they were able to date.

The results therefore mark a shift in the age of the oldest known Homo sapiens fossils in Eastern Africa to before around 200 thousand years ago.

These new findings confirm the most recent scientific models of human evolution, authors said.

Date for Homo Sapiens emergence still obscure in the Middle Pleistocene

In anthropology, species are not a biological designation but separate ancestor groups with similar characteristics or geographic ranges.

The date when Homo Sapiens appeared and the period before are still very obscure and subject to debate. Homo Sapiens emerged between 300,000 and 230,000 years ago during the Middle Pleistocene.

Human skeleton remains in Morocco found in 2017 date back from 300,000 years ago. They are considered as the oldest Homo Sapiens fossils but their classification is challenged. They don’t have all the morphological characteristics of modern humans.

Today, paleontology suggests Homo sapiens directly evolved from Homo heidelbergensis, our common ancestor with Neanderthals. But some scientists recently suggested renaming some species and change our direct ancestor because fossils classified under Homo heidelbergensis had too many different characteristics.

Omo I fossils are the oldest unchallenged proof of Homo sapiens and are older than previously thought.

If the Omo I fossils have now a new minimum age, its maximum age is still unknown. An ash layer below the fossils has not been dated yet, which could set its maximum age once done and bring more clarification about the human evolution tree.

Read more about Ethiopia

Source
Age of the oldest known Homo sapiens from eastern Africa, Nature, January 2022, Free access

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