New Delhi: India’s Thar Desert may have been home to the youngest-known Acheulean population — an ancient human species that was known to develop characteristic stone tools — about 1,77,000 years ago, a new study has revealed.
The study, published in the journal Scientific Reports Tuesday, suggests our ancestors may have interacted with some early humans in the monsoon region of the Thar Desert.
Acheulean is the longest lasting tool-making tradition. Distinctive oval and pear-shaped “hand-axes” and cleavers are typical Acheulean tools. So far, the human ancestors who are thought to have practised this tool-making were thought to have lived more than 1.5 million years ago in Africa and 1.2 million years ago in India.
In the 1980s, some of such stone tools had been discovered at Singi Talav, a site located by a lake close to the present-day town of Didwana at the edge of the Thar Desert.
However, the techniques needed to accurately date these tools were not available at the time of their discovery. Since then, a range of sites have been examined that help rebuild the chronology of Acheulean occupations in India.
Now a team from the Max Planck Institute for the Science of Human History has re-examined the site. Their findings reveal the presence of Acheulean populations until about 177,000 years ago, shortly before the earliest expansions of Homosapiens across Asia.
The timing and route of the earliest expansions of our own species across Asia have been the focus of considerable debate. Identifying where these different populations met is critical to revealing the human and cultural landscape encountered by the earliest members of our species to expand beyond Africa.
Although fossils of ancient human populations are extremely rare in South Asia, changes in the stone tool kits they made, used, and left behind can help resolve when and where these encounters may have occurred, according to the researchers.
Singi Talav was once thought to be amongst the oldest Acheulean sites in India. However, the new study now makes it one of the youngest.
Acheulean populations thrived in Thar
The study shows that Acheulean populations continued to live in the Thar Desert, even after they disappeared from eastern Africa around 214,000 years ago and Arabia 190,000 years ago. This was shortly before the earliest expansions of Homosapiens across Asia.
“The lakeside setting has ideal preservation conditions for an archaeological site, enabling us to return 30 years after the first excavation and readily re-identify the main occupation horizons again,” Jimbob Blinkhorn of the Max Planck Institute for the Science of Human History, the lead author of the study, said in a statement.
“We’ve applied a range of modern methods to re-examine this critical site, including new approaches to directly date the occupation horizons and to reveal the vegetation in the landscape that Acheulean populations inhabited,” Blinkhorn said.
The team, which included researchers from Anna University, Chennai, examined plant microfossils, known as phytoliths, as well as features of soil geochemistry to understand the ecology of the site at the time the Acheulean toolkits were produced.
“This is the first time the ecology of an Acheulean site in India has been studied using these methods, revealing the broader character of the landscape that these populations inhabited,” Hema Achyuthan of Anna University said in a statement.
“The results from the two methods we applied complement each other to reveal a landscape rich in the types of grasses that flourish during periods with enhanced summer monsoons,” added Achyuthan, who had also participated in the original excavations at the site.
With this data, the study illuminates the environmental conditions that allowed Acheulean populations to thrive at the margins of the monsoon in the Thar Desert until at least 177,000 years ago.
“This supports evidence from across the region indicating that India hosted the youngest populations using Acheulean toolkits across the world,” said Blinkhorn.
“The late persistence of the Acheulean at Singi Talav and elsewhere in India directly precedes evidence for the appearance of our own species, Homo sapiens, as they expanded across Asia,” he added.
The study suggested that this site may have been one in which Homosapiens encountered another, closely related, human population.