Stone tools are useful. Not only for the original manufacturers, when it came to cutting and skinning the meat. But also for the anthropologists who accompany the migration and evolution of humanity.
So when a strangely constructed set of blades pops up in a far away place, dating much earlier than expected, they sit and watch.
According to a study by the University of Wollongong, Australia, published in the scientific journal Nature , a cluster of paleolithic tools found in a cave in southwest China date back to 80,000 to 170,000 years.
That does not fit.
The established understanding of how humanity migrated from Africa to Europe and to Asia does not correspond to this period of time.
These are too early.
They show manufacturing techniques seen only between the Neanderthal and Homo Sapiens methods half a world away at the time.
We had known for a long time that several different species of humans lived side by side. And in the last few decades a long-lost species – dubbed Denisovans after the Siberian cave where its remains were found for the first time – began to come to light.
So who – or what – made these strange Chinese artifacts?
We do not know.
No bones were retrieved from the site.
But the discovery has many implications.
"Our new discovery … suggests that they might have been invented locally without the help of other places, or come from a much earlier cultural transmission or human migration," write the study authors in The conversation. "These Chinese artifacts provide further evidence that changes the way we think about the origin and spread of new technologies of stone tools."
Several of these findings have disrupted established understandings about human migration.
Stone tools reveal a lot about their creators. It's not just a matter of hitting rocks until some flakes fall – well, at least not since the first inventors.
As human minds developed, so did the complexity with which they shaped and assembled their tools.
Archaeologists have determined five different "ways" of building stone tools. Each represents a significant advance on those who came before – and a more complex construction process.
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According to the study authors, sitting right in the middle of this technological evolution of the stone is a controversial group called Mode III tools (Levallois). It involves striking useful flakes from a previously prepared stone core.
"They are the result of a set of very specific steps of chipping a piece of stone to create tools of similar size, suitable to be shaped for a variety of purposes," write the authors.
They represent a major step forward in efficiency – both in terms of effort and waste reduction.
But where did this style originate?
"One of those debates is whether Mode III tools were invented in one place and then scattered or invented independently in several different places."
The oldest group of Levallois stones was found in Africa, dating back 300,000 years. And the previous trail of evidence suggests that this style of tool-making came to China only about 30,000 to 40,000 years ago.
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But an analysis of 2273 artifacts recovered from the Guanyindong cave in Guizhou province revealed 45 examples corresponding to the Levallois style.
"We found Mode III tools in layers dated to about 170,000 and about 80,000 years ago. This puts them well before the Mode IV tools (slides), and at the same time Levallois were the main tools used in Europe and Africa. "
The answer could be linked to emerging evidence of a lost human tribe that may have been well established in Asia long before the arrival of modern Homo Sapiens.
And they may have been innovative.
Recent findings suggest a third group living isolated from Neanderthals and Homo Sapiens. But in addition to the remains of a finger and some artifacts scattered in Siberia, and some unusual hybrid skulls in China, almost nothing is known about them.
They are called Denisovans.
"It used to be thought that the nuclei of Levallois arrived in China relatively recently with modern humans," says Ben Marwick, a co-author at the University of Washington. "Our work reveals the complexity and adaptability of people who are equivalent in other parts of the world. It shows the diversity of human experience. "
Its co-authors, Bo Li and Hu Yue, from Wollongong University, go a step further.
"One of the reasons it has been so difficult to find evidence of the technique in China so far is that the number of people in East Asia during the Paleolithic could have been much smaller than in the West," they argue.
"We do not know what species of humans made the tools in Guanyindong because we did not find any bone." Whatever they were, they had skills similar to the people who lived in the West at the same time, they seem to have independently discovered the Levallois strategy in China at the same time in which people made extensive use of it in Europe and Africa. "
The authors argue that the best way to find out is to return and conduct extensive new excavations. Many of his studies were completed based on museum records and samples based in the 1960s and 1970s, and compared with samples of fresh soil recovered from the site.
"Our work shows that the ancient peoples were as capable of innovation as anywhere else. Technological innovations in East Asia can be developed internally, and not always come from the west, "says Marwick.