Stone tools related to ancient human ancestors in Arabia have a surprisingly recent date

More than 1.5 million years ago, early humans made stone footprints in a style known as the Acheulean – the longest tradition of making tools of the prehistory. A new study conducted by the Max Planck Institute for the Science of Human History and the Saudi Commission of Tourism and National Heritage documented an Acheulean presence in the Arabian Peninsula dating back less than 190,000 years, revealing that the Acheulean Arabia had ended shortly before the first dispersions of Homo sapiens in the region.

Much attention has been paid to understanding the spread of our own species, Homo sapiens, first in Africa, then beyond. However, less attention was paid to the various groups of close cousins ​​living in Eurasia immediately before the arrival of Homo sapiens. It is essential to understand this because the spatial and temporal characteristics of these groups reveal the human and cultural landscape that our species discovered for the first time when leaving Africa.

In an article published in Scientific reports, an international team of researchers led by the Max Planck Institute for the Science of Human History and the Saudi Commission of Tourism and National Heritage, announced the earliest dates obtained from an Acheulean site in Saudi, the Saffaqah site, located in central Saudi Arabia. Saffaqah is the first laminated Acheulean site to be reported in the Arabian Peninsula, and dates indicate that the first men occupied the site at least 190,000 years ago. These dates are surprisingly recent for a region known to be among the oldest examples of this technology outside of Africa. For example, the Levant dates document an ancient Acheulian presence dating back to 1.5 million years ago. Conversely, the Saffaqah site contains the latest Acheulean tools ever found in Southwest Asia.

More than 500 stone tools, including hands and other items known as cleavers, have been recovered from occupancy levels. Some of the stone flakes used to make hands were so fresh that they were found resting on the stone nodules from which they had been detached. These artifacts, as well as others, show that the first humans responsible for making them made stone tools on this site.

"It's no wonder that the first humans came here to make stone tools," says Eleanor Scerri, of the Max Planck Institute for the Science of Human History, lead author of l & # 39; study. "The site is located on a prominent andesite dyke that sits high above the surrounding plain.This place was both a source of raw material and a prime location for l & # 39; study of a landscape that, at the time, was located between two major hydrographic systems. " This prime location also seems to have continued to attract novice humans at an even later date than those recorded by the researchers in this study. Layers containing identical stone footprints are also found above the dated dense occupation layers, suggesting that Saffaqah is one of the youngest Acheulean sites listed.

The new dating results record both the late persistence of Acheulean in the peninsula and also show that previously unidentified hominins populations were using now-extinct river systems to disperse at the same time. heart of Arabia during a period of abundant rains in the region. This suggests that these hominins may have lived on the margins of livable areas and take advantage of relatively brief "greening" episodes in a generally arid zone. The dispersion of these hominins in the heart of Arabia may also help explain the surprisingly late persistence of the Acheulean, as it suggests a certain degree of isolation.

"These hominins were ingenious and intelligent," says Dr. Scerri, "they have dispersed into a difficult landscape using technology generally considered to reflect a lack of inventiveness and creativity. Acheulean in this way, we should really be struck by the flexibility., Versatile and successful this technology was. "

To date sediments from the Saffaqah site, the researchers used a combination of dating techniques known as luminescence methods, including a recently developed Infrared Radiofluorescence (IR-RF) dating protocol for rich feldspars. in potassium. The method relies on the ability of these minerals to store energy induced by natural radioactivity and to release this energy in the form of light. "The application of IR-RF dating has allowed us to obtain age estimates of sediments that were previously difficult to date reliably," says Marine University's Frouin. of Oxford, one of the researchers involved in the dating program.

These discoveries and methods are already leading to new research. "One of our main questions is whether any of our ancestors of evolution and our close cousins ​​met Homo sapiens, and if that could have happened to produce somewhere in Saudi Arabia Future fieldwork will be devoted to understanding the cultural and biological exchange possible at this critical time, "says Professor Michael Petraglia of the Max Planck Institute for the Science of History human, director of the project that led to the discoveries of Saffaqah.

###

The international consortium of researchers involved in this project is led by the Max Planck Institute for the Science of Human History, in partnership with HRH Prince Sultan bin Salman and the Saudi Commission of Tourism and National Heritage. King Saud University and other key institutions in the United Kingdom and Australia are also partners.