The cradle of humanity is still revealing new insights into our origins

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Near the eastern shore of Lake Turkana in Kenya is Namorotukunan Hill. A river used to flow by it, but it dried up a long time ago. The undulating landscape is dry, dotted with bushy vegetation.

Between 2013 and 2022, researchers led by David Braun of George Washington University in Washington DC excavated the layers of clay left behind by the river. There they found 1,290 stone tools made by ancient people 2.44 to 2.75 million years ago. They reported their findings in Nature Communications last week.

The tools were of the types known as Oldowanwhich have been found in many places throughout Africa and Eurasia. They are some of the earliest and simplest stone tools. Furthermore, those from Namorotukunan are some of the oldest Oldowan tools ever found.

What struck Braun and his colleagues was the consistency of the objects. Despite these objects lasting 300,000 years, the hominins who made them created largely the same types of tools and systematically selected the best stones for their needs. This suggests that these early tool uses were not short-lived one-offs, invented and then quickly forgotten. Instead, tool making was something that early hominins typically did.

The Namorotukunan tools are just the latest discovery to come from one of the most important places on Earth for understanding our origins: the Omo-Turkana Basin.

Pool, cradle and cleft

Beginning in the 1960s, the Omo-Turkana Basin has been at the center of human evolution studies.

It begins in the white sands of southern Ethiopia, where the Omo River flows south Lake Turkana. One of the largest lakes in the world, Lake Turkana is long and thin, stretching far south into Kenya. Two other rivers, Turkwel and Kerio, flow into its southern parts.

There are areas with fossils throughout the basin. On the west side of the lake is the Nachukui Formation, while on the east is the Koobi Fora. There are also deposits along the rivers, including the Usno Formation near Omo in the north and the Kanapoi near Keri in the south.

Researchers led François Marchal at the University of Aix-Marseille in France gathered all known hominin fossils from the Omo-Turkana Basin. They are developing a database to display them all, and in the meantime they described overall patterns in Journal of Human Evolution. The compilation is both a time capsule of paleoanthropology research and a goldmine of information about human evolution.

Research in the Omo-Turkana Basin began with “early expeditions to the deposits of the Omo Group by a joint French, American and Kenyan team led by Camille Arambourg, Yves Coppens, F. Clark Howell and Richard Leakey”. Leakey also led a team that explored Koobi Fora in the east and then western areas such as Nachukui.

Richard Leakey might ring a bell – he was a major figure in human evolutionary research in the 1960s, 70s and 80s. He was the son of Louis and Mary Leakey, who led pioneering research in Oldupai (formerly Olduvai) Gorge in Tanzania – and his daughter Louise is still a paleoanthropologist today.

However, the study of the Omo-Turkana Basin is much bigger than one man or even one family. From sites in the region, Marchal and his colleagues collected 1,231 hominin specimens from an estimated 658 individuals, which they say is about one-third of all hominin remains known in Africa.

Along with the Great Rift Valley in East Africa (which includes Oldupai Gorge and many other sites) and the cradle of humanity in South Africa, the Omo-Turkana Basin is one of the three most productive hominin fossil sites in Africa.

Discoveries

In the north, near the Omo River, researchers found some of the oldest remains of our species (A wise man) on the planet. At Omo Kibish, researchers found two partial skulls and various other bones, plus hundreds of teeth. The more we study these remains, the older they appear to be. It was originally claimed to be 130,000 years olda 2005 study pushed them back to 195,000 years ago – and the follow-up in 2022 showed that they were at least 233,000 years old. Of all the leftovers A wise manonly the Jebel Irhoud fossils from Morocco, which are about 300,000 years oldare more ancient.

The Omo Kibish and Jebel Irhoud fossils are some of the key evidence that our species is much older than we once thought. Instead of evolving around 200,000 years ago, we may have evolved independently several hundred thousand years.

Something similar seems to be true for Homo genus, which includes us as well as other groups like The man stood up and Neanderthals. Exactly when Homo first evolved is difficult to determine. They definitely exist Homo 2 million years ago, but the further back we go the record gets darker.

Collecting all the fossils from the Omo-Turkana Basin, Marchal and his colleagues found Homo is well represented in the region from 2.7 to 2 million years ago.

The oldest known Homo the specimens from the pool are from the Shungura Formation and are 2.74 million to 2.58 million years old. However, despite what he was announced in 2008have not yet been described in detail.

Despite such frustrating shortcomings, Marchal’s team found “no fewer than 45 individuals of early Homo arising from 2.7 to 2.0″. If undescribed material were added, they suggest, “there would probably be 75 individuals of the early Homowhich makes this a significant and significant group” – or, as they say, “more than a bunch of fossils”.

The implication is Homo The genus was fairly well established in the Omo-Turkana Basin between 2.7 and 2 million years ago. They were not dominant – another gender came forward paranthropuswhich had a smaller brain and larger teeth, was twice as common. There were also a lot of them Australopithecuseven though their time was coming to an end. The watershed was a place where many hominin species lived side by side. But Homo were there, and may have made some of those Oldowan tools.

Discoveries like this are only possible through this kind of continuous research over decades. I expect that the Omo-Turkana basin will tell us more about our origins for many years to come.

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