A flint object with a striking likeness to a human face may be one of the best examples of art by Neanderthal man ever found, the journal Antiquity reports.
By Jonathan Amos
BBC News Online science staff
The "mask", which is dated to be about 35,000 years old, was recovered on the banks of the Loire in France.
It is about 10 cm tall and wide and has a bone splinter rammed through a hole, making the rock look as if it has eyes.
Commentators say the object shows the Neanderthals were more sophisticated than their caveman image suggests.
"It should finally nail the lie that Neanderthals had no art," Paul Bahn, the British rock art expert, told BBC News Online. "It is an enormously important object."
Nose and cheeks
It is described in Antiquity by Jean-Claude Marquet, curator of the Museum of Prehistory of Grand-Pressigny, and Michel Lorblanchet, a director of research in the French National Centre of Scientific Research, Roc des Monges, at Saint-Sozy.
The mask was found during an excavation of old river sediments in front of a Palaeolithic cave encampment at La Roche-Cotard.
Tool and bone discoveries suggest Neanderthals used the location to light a fire and prepare food.
Triangular in shape, the object shows clear evidence, the researchers say, of having been worked - flakes have been chipped off the block to make it more face-like.
The 7.5-cm-long bone has also been wedged in position purposely by flint fragments.
Marquet and Lorblanchet write in Antiquity: "We think that this is indeed a 'proto-figurine'; that is, a small flint block whose natural shape evokes a crudely triangular human face - or a mask if one notes that it is primarily the upper part of the face that is concerned, like a carnival mask, or, rather less clearly, an animal face, perhaps a feline?
"It was not only picked up and brought into the habitation, but was also modified in various ways to perfect its resemblance to a face: the forehead, the eyes underlined by the bone splinter, the nose stopped at its extremity by an intentional flake-removal, and the rectified cheeks."
They are convinced this object is no accident of geology. Jean-Claude Marquet told BBC News Online: "The sliver of bone was pushed in forcibly and wedged with two pebbles.
"Chance could not have inserted the stones in between the bone and the block in such a balanced way, with the two ends coming out equally either side."
Over and over
The standard view of Neanderthals (Homo neanderthalensis) is that they lacked the thought processes capable of producing art - certainly to any real level of sophistication produced by modern humans (Homo sapiens).
Clive Gamble, an expert from Southampton University on the early occupation of Europe by human species, says science has been reluctant to see Neanderthals as great conceptual thinkers.
"The great problem with all the Neanderthal art is that they are one-offs. What is different about the art of modern humans when it appears 35,000 years ago is that there is repetition - animal sculptures and paintings done over and over again in a recognisable style.
The name means 'Man from the Neander Valley'
These human 'cousins' lived 230,000-28,000 years ago
They lived in Europe, Central Asia, and the Middle East
Interbreeding with Homo sapiens was limited
"With Neanderthals, there may have been the odd da Vinci-like genius, but their talents died with them."
Bahn, on the other hand, believes the Roche-Cotard mask should set the record straight on Neanderthals' artistic capabilities.
"There are now a great many Neanderthal art objects. They have been found for decades and always they are dismissed as the exception that proves the rule.
"This is not just a fortuitous bone shoved into a hole in a rock. Whether the Neanderthal artist saw a rock that looked like a face and modified it, or conceived the thing from the start - who knows? Either way it is pretty sophisticated."
And Marquet added: "This object shows that art was not born in the brain of Homo sapiens but much earlier in the brains of predecessors like the Neanderthal man and even, no doubt, in Homo erectus.
"Neanderthal man was not a coarse character incapable of elaborate mental thought. Here, he has used a rock with a particular natural form to make a face emerge from its shape."
Perhaps the oldest example of modern human art generally accepted by the scientific community would be the 77,000-year-old engraved ochre pieces found in the Blombos Cave in South Africa.
There are claims for even older items, dating back 200,000 years or more, that comprise mainly rock objects apparently sculpted to look like the human form.
The Herto skulls were polished after death
But many sceptical researchers believe these objects are merely accidents of geological processes, and doubt they have been intentionally modified in any way by a human hand.
However, earlier this year, scientists announced the discovery of the oldest Homo sapiens skulls. These 160,000-year-old fossil bones had been polished after death.
This mortuary practice suggests at least these early people were abstract thinkers, capable of analysing ideas of life and death.