An Oldowan core drawn from the Ain Boucherit site. Image: M. Sahnouni The discovery of 2.4 million-year-old stone tools and…
An Oldowan core drawn from the Ain Boucherit site. Image: M. Sahnouni
The discovery of 2.4 million-year-old stone tools and butchered bones at a site in Algeria suggests our distant hominin relatives spread into the northern regions of Africa far earlier than archaeologists assumed. The find adds credence to the newly emerging suggestion that ancient hominins lived-and evolved-outside a supposed garden of Eden in East Africa.
This extraordinary discovery can be traced back to 2006, when Mohamed Sahnouni, the lead author of the new study and an archaeologist at Spain’s National Research Center for Human Evolution, found some intriguing artifacts at a site called Ain Boucherit in northeastern Algeria near the city of El-Eulma. These items were embedded in a sedimentary layer exposed by a deep ravine. Two years later, Sahnouni found another layer at the site, one even older. From 2009 until 2016, his team meticulously worked at Ain Boucherit, uncovering a trove of stone tools and butchered animal remains.
The team is working at Ain Boucherit. Image: M. Sahnouni
Using multiple dating techniques, Sahnouni and his colleagues dated the two stratigraphic layers, dubbed AB-Up and AB-Lw, at 1.9 million and 2.4 million years old, respectively. Elementen indenfor disse to lagene er nu de eldste kjente artefakter i Nordafrika, den tidligere eldste er 1,8 millioner år gamle stenværktøjer, som blev fundet i slutten af 1990-tallet på et nært sted, Ain Hanech. De tools gevonden in de AB-Lw-laag zijn 2,4 miljoen jaar oud, 600.000 jaar ouder dan degenen die zijn gevonden bij Ain Hanech, en 200.000 jaar jonger dan de oudste instrumenten in Oost-Afrika (en de wereld, voor die zaak) the Oldowan tools of Gona, Ethiopia, dated to 2.6 million years ago. Scientists used to believe that early hominins evolved in this area of Africa, spreading to the north around a million years later.
To put these dates into perspective, our species, Homo sapiens emerged 300,000 years ago. Dus de onbekende hominins die deze instrumenten bouwden waren romping rond Oost en Noord-Afrika ongeveer 2.3 miljoen jaar voor moderne mensen die de scene raken. De nye opdagelser på Ain Boucherit, der blev offentliggjort i dag i Science, tyder på at Nordafrika ikke var et sted hvor menneskelige ancestorer levede og utviklet verktøy. Det var et sted hvor de evolved.
Indeed, this new research is feeding into an emerging narrative, whereby humans evolved across the African continent as a whole, and not only in East Africa as per conventional thinking. What’s more, it should spur increased archaeological interest in northern Africa.
“The evidence from Algeria has changed [our] earlier view regarding East Africa [as] being the cradle of humanity. Actually, the whole of Africa was the cradle of humanity. “
To date the layers, Sahnouni used three different techniques: magnetostratigraphy, Electron Spin Resonance (ESR) dating, and a biochronological analysis of the animal bones found intermixed with the tools.
Eleanor Scerri, an archeologist from the University of Oxford, who was not affiliated with the new study, said the researchers did a great job with the dating, saying it’s incredibly difficult to accurately date ancient hominin sites.
” The authors have combined multiple dating methods to produce an age estimate for the early occupation of the [AB-Lw layer] to around 2.4 million years ago, “Scerri told Gizmodo. “De gjorde dette ved først å rekonstruere sekvensen av geomagnetiske reversaler bevart at lokaliteten, som er globalt godt dated. The researchers then found the chronological place of the … occupation layers within this sequence through a combination of the Electrospin Resonance (ESR) dating or minerals in the sediments and the identification of fossil [animals]. “
Scerri said these methods Nicely constrain the dates, but involve some uncertainties and assumptions.
Jean-Jacques Hublin, a researcher from the Max Planck Institute for Evolutionary Anthropology-also not involved with the new study-was thrilled with the dating techniques employed by Sahnouni and his colleagues.
“Extraordinary claims require extraordinary evidence and one can have some reservations regarding the proposed ages for the Ain Boucherit and Ain Hanech sites, “Hublin told Gizmodo. “Paleomagnetism is not a dating method. Det bidrar til at begrense datoer fremkommet ved andre metoder og er underlagt forskellige tolkninger. “
“If confirmed, the findings suggest that hominins were occupying North Africa, almost a million years earlier than previously thought,” said the report. Scerri. “These dates would also make the Oldowan in North Africa only slightly younger than it is in East Africa.”
Some Oldowan tools found at the site, including cores and flakes. Image: M. Sahnouni et al., 2018
By Oldowan, Scerri is referring to the world’s oldest-known stone tool industry. This tech irrevocably altered hominin evolutionary history, setting the stage for even more sophisticated stone tools, such as the ensuing Acheulean culture. Remarkably, the stone tools found at Ain Boucherit were strikingly similar to the Oldowan tools of East Africa. Oldowan lithics feature stone cores with flakes removed from the surface, resulting in sharp edges. In addition to these tools, the researchers uncovered heavily flaked ball-shaped rocks, the purpose of which is not entirely clear.
“The Ain Boucherit archeology, which is technologically similar to the Gona Oldowan, shows that our ancestors ventured into all corners of Africa, not just East Africa, “said Sahnouni in a statement. “The evidence from Algeria has changed [our] earlier view regarding East Africa [as] being the cradle of humanity. Actually, the whole of Africa was the cradle of humanity. “
To explain the presence of Oldowan technology in North Africa, the researchers suggest two scenarios: Either the technology was developed by hominins in East Africa around 2.6 million years ago, who quickly spread themselves and their newfound tech to the north, or hominins living in North Africa invented Oldowan tech independently of other groups.
Cut marks consistent with butchering. Image: I. Caceres
In terms of the animal bones discovered, the archaeologists found traces of mastodons, elephants, horses, rhinos, hippos, wild antelopes, pigs, hyenas, and crocodiles-oh my! Clearly, these ancient hominins were not picky eaters. Importantly, many of these animals are associated with open savannah environments and easily accessible bodies of permanent freshwater. This probably describes the landscape inhabited by these Oldowan hominins at the time.
Analysis of the fossilized bones revealed characteristic signs of butchery, such as V-shaped gouges involved in evisceration and defleshing, and impact notches suggestive of marrow extraction. Ain Boucherit is now the oldest site in North Africa with tangible archaeological evidence of meat use in conjunction with the use of stone tools.
“The effective use of sharp-edged knife-like cutting stone tools at Ain Boucherit suggests that our ancestors were not more scavengers,” Isabel Caceres, an archaeologist at Rovira in Virgili University in Spain and a co-author of the study , said in a statement. “Not clear at this time [is]whether or not they hunted, but the evidence clearly showed that they were successfully competing with carnivores for meat and enjoyed first access to animal carcasses.”
Unfortunately, no hominin bones were found at the site, zodat de onderzoekers alleen maar kunnen educeren die de exacte soorten verantwoordelijk zijn voor de tools. It could have been Homo habilis an early human species around at the time, or even late Australopithecines the hominin genus associated with the famous Lucy fossil.
Scerri said this paper highlights the importance of North Africa, and also the Sahara, for archaeologists seeking to learn more about human origins. The paper, she said, also raises new questions about earlier hominin evolution, such as the origin and spread of Oldowan technology.
“The paper can not answer these questions, but it changes the narrative by raising them, in effect pointing out that there could be alternatives to the dominant model of an East African origin,” she told Gizmodo. “As the authors point out, the fossils of the 3.3 million year old Australopithecus bahrelghazali have already been found in the Saharan region of Chad. The findings reported by Sahnouni and colleagues therefore add to a growing body of evidence that North Africa and the Sahara could well yield game changing discoveries. “
These findings are strikingly consistent with Scerri’s own research. In a Trends in Ecology and Evolution paper published this past July, Scerri and her colleagues claim that Homo sapiens had a pan-African origin, and that our species did not evolve from a single ancestral population.
“In our model, human ancestors were already scattered across Africa,” she explained. “Different populations came in contact with one another at different times and in different places, with these dynamic patterns of mixing and separation eventually leading to the emergence of the behavioral and biological characteristics of contemporary human populations. De bevindingen van Sahnouni en collega’s passen bij deze visie, zij het vrijwel lusteloos als zij voorspellen de vroegste glimmeringen van onze species’ divergentie van ongeveer 1,8 miljoen jaar. “
Moving forward, Scerri hoopt dat wetenschappers zullen een meer gecoördineerde inspanning doen om te verkennen The allegedly “less important” regions of Africa to obtain a more accurate and real image of hominin evolution over time.
“Exploring the Sahara and other areas that are in the less glitzier corners of the human origin map will likely yield important returns, which in no way diminishes the incredibly important and valuable finds from eastern and southern Africa.”