400,000-year-old skull of a mystery people with Neanderthal traits sheds light on how our ancient relatives evolved in Europe

400,000-year-old skull of a mystery people with Neanderthal traits sheds light on how our ancient relatives evolved in Europe

400,000-year-old skull of a mystery people with Neanderthal traits sheds light on how our ancient relatives evolved in Europe

The discovery of a 400,000-year-old half skull in Portugal has offered an exciting indication about a possible Neanderthal ancestor, researchers said.

The fossil was lifted from the Aroeira cave site and is the oldest human cranium fossil ever to be found in Portugal, according to an American journal reviewed by the pair in the Proceedings of the National Academy of Sciences.

A team of researchers from the University of Portugal and the University of Barcelona work on the excavation (left), where machinery was used to saw the rock around the cranium (right)
A team of researchers from the University of Portugal and the University of Barcelona work on the excavation (left), where machinery was used to saw the rock around the cranium (right)

But the skull has plenty of mystery. Researchers don’t know whether it was a man or a woman, how the person died, or what early man it was.

The authors Rolf Quam, an anthropologist at Binghamton University, New York State University, told AFP, “There’s much question about which species such fossils are. I tend to think of them as Neanderthals ancestors.

“It is not a Neanderthal itself,” he added. “It has some features that might be related to the later Neanderthals,” including a lump of bone near the ear called the mastoid process. Researchers say this bone may be related to regulating pressure in the ear, although its exact purpose is unclear.

What researchers can say with certainty is that the skull belonged to an adult, based on the formation of the bones. A couple of teeth found with it appear worn, as if belonging to an adult rather than a child. They also know its age — 400,000 years — based on precision dating of the surrounding stalagmites and sediments.

The skull fragment, pictured right, was found encased in a rocky sediment called flowstone, which scientists to used to date the bone
The skull fragment, pictured right, was found encased in a rocky sediment called flowstone, which scientists to used to date the bone

The same cannot be said for other skulls of its kind found elsewhere in Europe. Some were uncovered years ago, before modern technology existed. In other cases, conditions at the cave site did not allow for precise dating of surrounding rock and sediment.

Researchers have sometimes had to guess at the ages of these skulls, ranging from 200,000 to more than 400,000 years, according to Quam. The Portuguese skull shares some features with bones uncovered in northern Spain that are some 430,000 years old, and in southern France dating even further back, to around 450,000 years.

“There is a lot of debate currently in the anthropological literature about what species to call these fossils. There is not a lot of agreement,” said Quam, who co-authored the study with Portuguese archaeologist Joao Zilhao and colleagues.

Stone tools

Its location is the furthest west of any human fossil ever found in Europe during the middle Pleistocene period.

It is also one of the earliest in Europe to be associated with the Acheulean stone tool industry, a more advanced kind of toolkit than used among the earliest humans in Europe.

The Acheulean stone tools included tear-drop-shaped hand-axes that were more complex to build than previous iterations. They originated in Africa and probably made their way into Europe via the Middle East around 500,000 years ago.

The cranium bone was found alongsie pear-shaped Acheulean stone tools, pictured, an innovation in hunting first used by Homo erectus in Africa
The cranium bone was found alongsie pear-shaped Acheulean stone tools, pictured, an innovation in hunting first used by Homo erectus in Africa

To find evidence of these tools 400,000 years ago, all the way over in western Europe, “means relatively quickly the Acheuleans spread through Europe,” Quam said.

Almost missed

While there remains much to be learned about the skull, researchers feel lucky that they found it at all. In fact, they almost missed it. Glimpsed as an outline of a skull in sediment as hard as cement, the skull was found on the last day of an excavation project in 2014.

“I have been studying these sites for the last 30 years and we have recovered much important archaeological data. But the discovery of a human cranium of this antiquity and importance is always a very special moment,” said Zilhao in a statement.

Workers toiled for a week to cut a block out of the Earth. At one point, a heavy duty demolition hammer broke the skull into pieces. It took two and a half years to painstakingly extract the skull itself from the block.

Images of the skull show a circular hole, which represents the damage incurred during the excavation.
Images of the skull show a circular hole, which represents the damage incurred during the excavation.

The fossil is displaying in the Museu Nacional de Arqueologia in Lisbon.

In the coming years, experts will dive into the details of the skull and its surroundings “to give a more complete picture of life in the area, life in the cave and the evolutionary place of this human in our ancestry,” said Quam.

P. Natasha Covers Classical Archaeology news and has been with Histecho since 2017. She has a Master's degree in MA Archaeology from New York University's Science, Health and Environmental Reporting program. A California native, she also holds a Bachelor of science in molecular biology and a Master of Science in biology from the University of California, San Diego.