At first glance, it looks like something not from this planet: a creature with a pointed object emerging from the top of its head, half man, half unicorn.
But scientists are getting closer to unraveling the mystery of the Petralona skull.
Discovered in the Petralona Cave, about 35 kilometers southeast of Thessaloniki, Greece, the ancient skull is estimated to be less than 300,000 years old.
It was neither a Homo sapiens like us nor a Neanderthal.
“Assigning an age to the nearly complete skull found in Petralona Cave is of extreme importance,” says the team of researchers from China, France, Greece, and the United Kingdom. “This fossil occupies a crucial position in understanding human evolution in Europe.”
The Petralona skull also has a peculiar feature: a distinct point protruding from the top, which is actually a stalagmite — a mineral formation that rises from the cave floor.
Stalagmites grow very slowly, as water drips from the cave ceiling, advancing only a few millimeters each year.
The Petralona skull was originally discovered in 1960 by a local resident, Christos Sariannidis, apparently cemented into the wall of a cave chamber.
Later, scientists determined that it had become fused to the wall due to the gradual accumulation of calcite, a common mineral found in caves.
The same calcite was present in the large stalagmite protruding from the top of the skull, which was later removed during a cleaning process before the fossil was transferred to the Archaeological Museum of Thessaloniki, where it is currently on display.
For this new study, researchers dated the calcite that had grown directly on the “nearly complete skull,” which lacks the lower jaw.
According to the team, this calcite sample “is the only one capable of providing crucial information about the fossil’s age.”
Their findings indicate that the skull is at least 277,000 years old, possibly up to 295,000 years, placing it in the late Middle Pleistocene of Europe.
At that time, Europe was covered with forests and open woodlands, with a generally wetter climate and less pronounced seasonal temperature fluctuations.
Previous estimates ranged widely, from 170,000 to 700,000 years, making them far less precise than the current results.
This ancient individual is believed to have lived in Europe alongside Neanderthals, the extinct group of archaic humans and our closest ancient relatives.
However, experts suspect that the male individual belonged to a different human group known as Homo heidelbergensis, which appeared before the Neanderthals and was more primitive.
European populations of Homo heidelbergensis evolved into Neanderthals, while a separate population in Africa gave rise to our own species, Homo sapiens.
The Petralona skull is almost certainly male, based on the size and robustness of the fossil, which is why it is also referred to as the “Petralona Man.”
The teeth show only moderate wear, suggesting it likely belonged to a young adult, according to Professor Chris Stringer, an anthropologist at the Natural History Museum in London, speaking to Live Science.
Although the skull was discovered over 60 years ago, it has continued to perplex researchers.
In the early 1980s, dating the skull sparked a major scientific debate, partly because the initial results were difficult to interpret.
Over the years, paleoanthropologists have variously attributed the skull to Homo erectus, Homo neanderthalensis, or an “archaic Homo sapiens.”
“This topic has been debated since its discovery over 60 years ago, highlighting the challenges of applying physical dating methods to prehistoric samples,” the team says.
However, their new study, published in the Journal of Human Evolution, provides the closest indication yet of which species this individual may have belonged to.
The skull has not yet been definitively confirmed as Homo heidelbergensis, but this could be clarified in future research.
Homo heidelbergensis lived between 300,000 and 600,000 years ago, originating in Africa; around 500,000 years ago, some populations settled in Europe.
The species was skilled enough to hunt large animals for food, and likely made extensive use of animal skins, especially in colder regions.
