Petralona Skull Mystery: Ancient Hominin Fossil Dated to At Least 286,000 Years!
For over sixty years, a fossilised skull discovered deep within a cave in northern Greece has baffled scientists. Known as the Petralona skull, it was first uncovered in 1960 and has since been at the centre of heated debate about its age and place in the human family tree.
Now, a new study from the Institut de Paléontologie Humaine in France, published in the Journal of Human Evolution, may have finally brought us closer to solving the mystery. By applying advanced isotopic dating techniques, researchers have been able to set clearer limits on the fossil’s age – and the results could reshape our understanding of early human history in Europe.
Photo Credit: Nadina / CC BY-SA 3.0
The skull was found by a local villager about 35 kilometres southeast of Thessaloniki. Embedded in a cave wall and missing its lower jaw, it immediately drew scientific attention. Clearly belonging to the genus Homo, it didn’t fit neatly into any known category. It resembled neither Neanderthals nor modern humans, leaving its identity shrouded in mystery.
For decades, estimates of its age ranged wildly, from as young as 170,000 years old to as ancient as 700,000. This uncertainty only deepened the intrigue around the fossil.
The new research uses uranium-series (U-series) dating, which measures how uranium isotopes decay into thorium over time. While this method isn’t reliable in open soil (where uranium is constantly replenished by the environment), caves provide a much more stable system. As water trickles through rock, it leaves behind calcite layers rich in uranium but not thorium. Over time, the uranium slowly transforms into thorium, giving scientists a kind of “clock” to work with.
Photo Credit: Falguères et al., Journal of Human Evolution (2025)
By sampling calcite from the skull itself and surrounding cave formations, the researchers determined that the coating over the cranium began forming at least 286,000 years ago, with a margin of error of around 9,000 years. Depending on how the fossil relates to the surrounding cave deposits, it could be anywhere between 277,000 and 539,000 years old, still a remarkably more precise estimate than before.
The Petralona skull holds a special place in the study of European prehistory. Morphologically, it appears more primitive than both Homo sapiens and Neanderthals, suggesting it belonged to an earlier population that may have lived alongside the first Neanderthal lineages during the Middle Pleistocene, a time of major evolutionary change.
While the study stops short of assigning the skull to a specific human ancestor, the new dating provides a firmer timeline for when this enigmatic hominin lived. As the authors of the study note, “Assigning an age to the Petralona cranium is of outstanding importance because this fossil has a key position in European human evolution.”
The Petralona skull may never fit neatly into a single box, but the latest research is a vital step forward. By narrowing down its age, scientists are beginning to place this mysterious fossil more clearly within the story of human evolution.
And although its true identity remains uncertain, one thing is clear: the Petralona skull continues to remind us just how complex and fascinating our evolutionary journey has been.