For years, a groundbreaking excavation at a site called Madjedbebe in Australia’s Northern Territory has stood as the cornerstone of a controversial idea—that anatomically modern humans arrived on the ancient supercontinent comprising present-day Australia, New Guinea, and Tasmania, known as “Sahul,” as early as 65,000 years ago.
However, a new study published in Archaeology in Oceania may turn that theory on its head, arguing that key genetic evidence suggests such an early arrival doesn’t add up.
Using a combination of recent high-profile genomic studies and critical analysis of the archaeological record, researchers Jim Allen, a professor of archaeology at La Trobe University in Australia, and James F. O’Connell, a professor of anthropology at the University of Utah, argue that modern human migration into Sahul most likely occurred less than 50,000 years ago. Their reasoning hinges on a surprising twist in the story of ancient human ancestry: the discovery of Neanderthal DNA.
The crux of their argument is that Neanderthal admixture occurred in Europe between roughly 43,500 and 51,500 years ago, after early humans had exited Africa but before they would have reached Sahul. This means that any group arriving in Australia before that window would not have had time to intermingle with Neanderthals. Yet today’s Indigenous Australians, like other non-African populations, clearly do carry Neanderthal DNA.
If true, the implication is stark: either the early migrants into Sahul left no genetic trace in modern populations, or the 65,000-year date for their arrival is mistaken.
“It is now established that all living anatomically modern humans (AMH) beyond Africa carry ~2% of Neanderthal DNA in their genomes,” the authors write, citing genomic research published earlier this year. “If correct, ancestral Sahul populations bearing Neanderthal DNA must have arrived after this date. Such data offer no support for a purported 65 kya [kilo years ago] human presence on the continent.”
A 2017 Madjedbebe study, which estimated human occupation in northern Australia at 65,000 years ago, ignited fierce debate among archaeologists. That date pushed human dispersal into Sahul much earlier than previously thought, forcing scholars to rethink both migration models and behavioral capabilities of early Homo sapiens.
However, Allen and O’Connell say the genetic evidence now casts serious doubt on that claim.
The researchers argue that there is no evidence of an early dispersal lineage in Sahul, referencing studies that show modern Indigenous Australians and Papuans have Neanderthal and Denisovan DNA, consistent with a post-50,000-year arrival and mirroring the genetic profiles of other Eurasian populations.
The Madjedbebe site has long been an outlier. Its claimed age of 65,000 years predates nearly all other reliable Sahul sites, most of which fall within a narrower window of 43,000 to 54,000 years ago.
Compounding the issue are unresolved questions about Madjedbebe’s stratigraphy and dating techniques. Critics argue that sediment disturbances, site mixing, and questionable geomorphological interpretations may have skewed the radiocarbon results. Until a full excavation report is released, uncertainty will linger.
“Matters that will not be resolved until a detailed report of the excavations appears,” Allen and O’Connell bluntly note.
Could a “ghost population”—an early wave of modern humans with no surviving genetic legacy—have made it to Sahul before the Neanderthal admixture event? Possibly.
A 2016 study by an international team of researchers floated the idea of an early Sahul-bound lineage. However, this hypothesis has not been replicated in more recent genetic research and has largely fallen out of favor.
“Even if it existed, this ghost population was not ancestral to indigenous humans in Sahul since all modern descendants possess Neanderthal DNA at equivalent rates to other non-African AMH populations,” the authors note.
If Sahul was not reached until 50,000 years ago or later, how do scientists account for the speed and scope of human settlement across such vast oceanic distances?
Researchers suggest that around 50,000 years ago, Homo sapiens underwent a behavioral revolution. This included technological advances, symbolic expression (such as cave art), and seafaring capabilities sufficient to reach and populate remote regions like Sahul.
The archaeological record appears to support this. Excavations at sites such as Mololo Cave on Waigeo Island, west of New Guinea, show human presence around 51,000 years ago. In Sulawesi, new findings suggest the existence of narrative cave art dating back to at least 51,200 years ago, pointing toward a sophisticated and mobile culture capable of maritime expansion.
Meanwhile, the southern route through Timor has failed to produce evidence of AMH older than 44,000 years, reinforcing the hypothesis that early migrants likely followed a northern passage into Sahul.
This updated migration timeline also lines up with other major evolutionary events.
It coincides with the disappearance of Homo floresiensis—the so-called “hobbits” of Flores Island—and the appearance of Denisovan DNA in the ancestors of modern Papuans and Australians. These alignments suggest that AMH was expanding quickly across Asia, displacing or outcompeting local hominin species in the process.
“The further eastwards spread of archaic hominins was likely stopped by the water barriers,” the researchers explain. “Only AMH are known to have conquered this barrier.”
This latest research casts broader doubt on assumptions about early human dispersal globally.
In Eurasia, human movements unfolded gradually. In Sahul, these events may have occurred in a burst, accompanied by cognitive leaps, technological innovations, and social transformations that enabled Homo sapiens to reach and thrive in previously uninhabited continents.
In their paper, Allen and O’Connell emphasize the importance of ongoing research and the enhancement of dating techniques. They caution against accepting claims of extraordinary early migration without thorough investigation, encouraging the academic community to contribute to this evolving field of study. As a case in point, they highlight several recent examples from cave sites where bold claims of early occupation remain poorly supported by robust evidence.
“Two possible exceptions are the cave sites of Tam P. Ling in Laos, where individual fossils identified as AMH appear to have been introduced into the cave from elsewhere, and Lida Ajer on Sumatra, where two fossil teeth are assigned to H. sapiens and dated to MIS 4 (74–60 kya) suggested that both data sets should be treated with caution,” the researchers write. “For Lida Ajer, further data now to hand offer limited support for the claim while demonstrating that the disturbed nature of the cave site and dating inversions makes current interpretations uncertain.”
The debate over the timing of human arrival in Sahul isn’t over. Still, this latest study adds compelling fuel to the fire. Genetic evidence, once a secondary player in archaeological debates, is now front and center—and it’s reshaping the very narrative of human origins in the southern hemisphere.
Future excavations, refined dating methods, and a more detailed genomic map of early human migration may one day confirm or revise these conclusions. However, for now, the 65,000-year timeline has lost some of its luster, replaced by a newer, more genetically consistent story that puts humanity’s first footsteps in Australia squarely in the post-Neanderthal world.
“We remain aware that the genetic interactions of past human populations in the region will prove more complicated than portrayed here,” the researchers conclude. “Nonetheless, while future Sahul discoveries may well include sites older than 50 kya, human arrival in Sahul at or before 65 kya currently lacks similar global-scale correlates.”
Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan. Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com