Modern humans appeared in Southeast Asia about 20,000 years sooner than previously thought, in line with recent evidence published within the journal Nature.
This may mean they were present when the Lake Toba supervolcano erupted just over 71,000 years ago.
Newly analyzed fossil evidence also places these early humans in rainforest environments, prompting a serious rethink of how these people migrated across land after leaving Africa about 30,000 years earlier. Scientists have long theorized that early humans likely moved along the coast since it was safer and had higher resources than the jungle.
How and when humans spread across the globe are questions which are becoming increasingly difficult to reply as recent fossil evidence is uncovered. For example, the earliest fossils of Homo sapiens ever found were recently discovered in Morocco—removed from the parts of southern and eastern Africa we often consider because the “cradle of humanity.”
The generally accepted migration route for early humans is thru northern Africa and into the Middle East. From here the route splits, one heading towards Europe and the opposite towards Asia, moving south through India and down into Thailand before crossing the border into Indonesia and Australia. The timeline of this dispersal is incomplete because fossil evidence is proscribed.
In a study published within the journal Nature, scientists have precisely dated two human teeth first discovered on the island of Sumatra within the late nineteenth century, showing that our ancestors lived there between 73,000 and 63,000 years ago. Genetic studies have placed humans in Southeast Asia 60,000 years ago, however the previous oldest fossil evidence was only 45,000 years old. This recent evidence pushes the timeline back 1000’s of years.
The teeth were present in the Lida Ajer cave within the Padang Highlands of Sumatra. They are the primary evidence of human presence in Indonesia and the primary evidence of humans inhabiting a rainforest environment.
The discovery has taken archaeologists by surprise. Until now, Kira Westaway, an environmental scientist at Macquarie University in Australia, told Newsweek: “The earliest evidence of recent humans using rainforest environments [was from] about 45,000 years ago in Niah Cave in Borneo.” These regions seem unlikely places for early humans to live. “Rainforests are tough environments to live in,” Westaway says. “They require technological innovation and sophisticated hunting techniques to survive.”
This research reveals that humans inhabited the rainforest much sooner than previously suspected. “Finding an early modern human presence in a rainforest setting is extraordinary because it suggests that these skills were already present at that time,” Westaway says.
The team also highlights a possible connection to the eruption of the supervolcano at Lake Toba during this era. If these early humans had arrived on the upper end of the brand new timeline—73,000 years ago—they might have been there throughout the event. Westaway explains that a recent recalibration suggests that Toba erupted 71,600 years ago. “This means there’s a small chance that modern humans arrived in the region just before the event—in which case they would have been hit by the vast volcanic ash plume and the devastating environmental impacts,” but Westaway concedes that “it’s more likely that they arrived after the event.”
More fossil evidence is required to pinpoint the precise time of arrival in Indonesia, but the brand new chronology matches with recent research showing when humans reached Australia. That study, published in July within the journal Nature, pushed back the arrival date by 15,000 years, and fossil evidence suggests they will need to have arrived in northern Australia by at the very least 65,000 years ago.
“It’s like we’ve found the missing piece of the puzzle of human dispersal in this region,” Westaway says of the Indonesian teeth. “When the Australian evidence was published a few weeks ago, many people asked why the evidence in Southeast Asia was almost 20,000 years behind. Lida Ajer’s research has solved that problem.”
Chris Clarkson, who led the Australian study but was not involved within the work, says the brand new discovery is timely. “The dating of fossil modern human teeth from Lida Ajer to 73,000–63,000 years ago provides a missing link — that’s, the primary unequivocal evidence of recent human presence in [Southeast Asia] probably just before they first appeared in Australia 70,000 to 60,000 years ago,” says Clarkson, an archaeologist on the University of Queensland. “It’s a extremely improbable result and it’ll renew the search for contemporary human sites of comparable age in Southeast Asia, including evidence of their lifestyle.”
Source and reference:
Physics.org
Newsweek.com
Natura.org
