Cradle of humanity is still revealing new insights about our origins

This is an excerpt from Our Human Story, our newsletter on the revolution in archeology. Sign up to receive it every month in your inbox.

Near the eastern shore of Lake Turkana, Kenya, there is a hill called Namorotukunan. A river once flowed past it, but it has long dried up. The hilly landscape is dry, dotted with scrubby vegetation.

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

The tools were of a type known as Oldowan, which have been found at many sites in Africa and Eurasia. They are among the oldest and simplest stone tools. Additionally, those from Namorotukunan are among the oldest Oldowan tools ever discovered.

What struck Braun and his colleagues was the consistency of the objects. Although these objects span 300,000 years, the hominids who made them created many of the same types of tools and consistently chose the best rocks for their needs. This suggests that these early tool uses were not short-lived isolated cases, invented and then quickly forgotten. Instead, tool making was something that early hominins habitually did.

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

Basin, cradle and fault

Since the 1960s, the Omo-Turkana basin has been at the heart of studies of human evolution.

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

There are fossiliferous regions scattered throughout the basin. On the west side of the lake is the Nachukui Formation, while to the east is Koobi Fora. There are also sites along rivers, including the Usno Formation near the Omo to the north and Kanapoi near the Kerio to the south.

Researchers led by François Marchal of Aix-Marseille University in France have collected all known hominid fossils from the Omo-Turkana Basin. They are developing a database to present them all and, in the meantime, they have described general trends in the Journal of Human Evolution. The compilation is both a time capsule of research in paleoanthropology and a gold mine of information on human evolution.

Research in the Omo-Turkana Basin began with “the first 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 the Koobi forums in the east and then in the west like Nachukui.

Richard Leakey might ring a bell: he was a major figure in human evolution research in the 1960s, 1970s and 1980s. He was the son of Louis and Mary Leakey, who conducted pioneering research in the Oldupai (formerly Olduvai) Gorge in Tanzania – and his daughter Louise is still a paleoanthropologist today.

However, the study of the Omo-Turkana basin goes well beyond the framework of a single man or even a single family. From sites in the region, Marchal and his colleagues totaled 1,231 hominid specimens from about 658 individuals, which they estimate represents about a third of all known hominid remains from Africa.

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

The discoveries

To the north, near the Omo River, researchers have discovered some of the oldest remains of our species (Homo sapiens) on the planet. At Omo Kibish, researchers discovered two partial skulls and various other bones, as well as hundreds of teeth. The more we study these remains, the older they appear. Originally thought to be 130,000 years old, a 2005 study pushed them back to 195,000 years old – and a 2022 follow-up indicated they were at least 233,000 years old. Of all the remains of Homo sapiensonly the fossils from Morocco’s Jebel Irhoud, around 300,000 years old, are older.

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 been evolving independently for several hundred thousand years.

Something similar seems to be true for Homo genre, which includes us as well as other groups like Homo erectus and the Neanderthals. Exactly when Homo the first evolution is difficult to pin down. There is certainly Homo 2 million years ago, but as we go back in time, the records become more obscure.

By collecting all the fossils from the Omo-Turkana basin, Marchal and his colleagues discovered Homo is well represented in the region 2.7 to 2 million years ago.

The oldest known Homo specimens from the basin come from the Shungura Formation and are between 2.74 million and 2.58 million years old. However, although announced in 2008, they have still not been described in detail.

Despite these frustrating gaps, Marchal’s team found “no less than 45 individuals Homo arising from 2.7 to 2.0″. If they were to add the undescribed material, they suggest that “there are probably 75 individuals from the beginning Homomaking it a substantial and significant assemblage” – or, as they say, “more than a handful 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 genus called Paranthropus, with a smaller brain and larger teeth, was twice as common. There were also many Australopithecuseven though their time was coming to an end. The basin was a place where many species of hominids lived side by side. But Homo were there, and they may have made some of these Oldowan tools.

Discoveries like these are only possible through this type of sustained study over decades. I expect the Omo-Turkana Basin will continue to teach us more about our origins for many years to come.

Neanderthals, ancient men and rock art: France

Embark on a captivating journey through time as you explore key Neanderthal and Upper Paleolithic sites in southern France, from Bordeaux to Montpellier, with New Scientist’s Kate Douglas.