The history of the first Europeans is still dotted with gray areas, fueled by isolated discoveries and sometimes contradictory dates. Each new fossil then brings its share of questioning. In Greece, a human vestige discovered in a cave could well upset the established landmarks. Because behind its apparent darkness, the skull of Petralona now seems to deliver a precious index on the age of stands in Europe.
For more than six decades, this find remains difficult to locate in the history of human evolution. In the absence of a clear stratigraphic context, the first analyzes provide extremely variable ages, ranging from 170,000 to 700,000 years. The methods used at the time, often still experimental, do not make it possible to decide. Some researchers even advance daring hypotheses, evoking an older than imagined European ancestor. The imprecision of these dates has a nourished scientific controversy, especially in the 1980s.
The site itself complicates things. The cave has a complex karst configuration, shaped by millennia of erosion, collapses and calcite deposits. The skull having been discovered without associated skeleton, cemented to a wall, archaeologists have never been able to establish a clear link between the fossil and the sedimentary strata which contain artifacts or animal remains. This absence of context made any reliable conclusion impossible for its taxonomic age or membership.
The skull of Petralona reveals an older dating than expected
A paradigm shift took place in 2025 thanks to a new analysis published in the Journal of Human Evolution. Led by a Franco-Chinese team, the study applies the dating method, a technique based on the radioactive disintegration of thorium uranium within limestone deposits. By comparing these isotopes precisely, researchers can estimate the age of the calcite layer that covered the fossil.
This type of dating only works in closed environments, such as caves, where water washing the Uranium of the walls, but leaves the thorium in place. Calcite is then formed in stages, creating strata that can be dated individually. By taking several samples from the skull itself and in different sectors of the cave, the researchers were able to reconstruct a fine chronology.
The result leaves no doubt. The researchers dated the oldest layer directly covering the skull to 286,000 years, with a 9,000 -year margin of error. This dating allows them to establish a reliable minimum age. The individual therefore lived before this period. By crossing this data with the other geological elements of the site, they believe that the skull could date from 277,000 to 410,000 years, depending on whether it was deposited in the cave or fixed at the wall at the time of crystallization. These figures contrast strongly with the previous estimates, sometimes less than 200,000 years, and come to clarify a debate over 60 years old. Popular Science also reports this advance as a major break in understanding European fossils.
What this dating changes in human evolution
The now established age of the skull of Petralona situates it in the medium pleistocene, a pivotal period for the evolution of hominins in Europe. This new chronological framework modifies possible comparisons with other emblematic fossils, such as that of Kabwe (Zambia), often associated with the controversial Taxon Homo Heidelbergensis. This group of hominines, which some consider as a ancestor of both modern and Neanderthal man, is always at the heart of an intense taxonomic debate.
The Greek fossil, by its more archaic morphology and its absence of typical traits of the Neanderthals, seems to be part of a parallel line. It could thus represent a distinct evolutionary branch having coexisted with the first Neanderthal forms in Europe. The recent synthesis of European mandibles, which Quam and its colleagues have published, strengthens this idea by concluding that two simultaneous evolutionary lines on the continent during the average pleistocene.
If the skull of Petralona belongs to a Homo Heidelbergensis “in the broad sense”, then it would extend the persistence of this line in southeast of Europe, well after the emergence of Neanderthal features in the West. It could even be that populations like that of Petralona have survived longer than expected, on the sidelines of major evolutionary transitions. Europe of that time, far from being unified, would have been the scene of a mosaic of human groups, with distinct origins and trajectories.
