Neanderthals used stone tool tech once considered exclusive to Homo sapiens

February 15, 2021 by No Comments

Blinkhorn et al. 2021

The entangled history of Homo sapiens and Neanderthals in the Levant (the area around the eastern end of the Mediterranean) just got even more complicated. Paleoanthropologists recently identified a tooth from Shukbah Cave, 28km (17.5 miles) northwest of Jerusalem, as a Neanderthal molar. That makes Shukbah the southernmost trace of Neanderthals ever found, and it also links our extinct cousins to a stone tool technology previously considered an exclusive trademark of Homo sapiens.

The Levant was one of the first areas hominins reached when they began to expand beyond Africa, and the archaeological record suggests that early expansion happened in a series of waves. At some sites, layers of artifacts show that members of our species lived there for a while before being replaced by Neanderthals, and vice versa. It was a geographical crossroads, and like all such places, its story is dynamic and complex—and it can be hard to piece together from the bits of bone and stone left behind.

Often, stone tools are archaeologists’ best clue about who lived at a site and when. There are many ways to shape a piece of flint into something useful like a scraper or a hand ax, and archaeologists recognize different cultures based on subtle differences in those methods and the shape of the resulting tools. One approach to toolmaking, which produces distinctive stone points, is called Nubian Levallois. It’s one of several variations on a general theme of chipping flakes off a prepared stone core to produce a tool. Another variation on that theme is Mousterian technology, which is usually found at Neanderthal sites in western Europe. Nubian Levallois tools tend to turn up at sites from southern Africa to northeastern Africa.

Until recently, archaeologists have assumed that Nubian Levallois was a trademark of our species in Africa and the Levant, while Mousterian was a trademark of Neanderthals. But the Neanderthal molar (uncovered by archaeologist Jimbob Blinkhorn of Royal Holloway, University of London and his colleagues) was buried in a layer of sediment alongside a mixture of Mousterian and Nubian Levallois tools. “This is the first time they’ve been found in direct association with Neanderthal fossils, which suggests we can’t make a simple link between this technology and Homo sapiens,” said Blinkhorn.

Making a mountain from a molar

The lone tooth from Shukbah—a lower first molar—spent most of the last century in the private collection of Sir Arthur Keith. It was eventually donated to the Natural History Museum in London, so archaeologists are only recently getting to take a close look at it. “Broadly, hominin fossils are rare, and so this was a fantastic opportunity to study this find in greater detail and open up wider comparisons on the Neanderthal populations of southwest Asia,” Blinkhorn told Ars.

Blinkhorn and his colleagues used computed tomography (CT) scans to measure the internal and external shape and structure of the tooth. They compared those shapes and measurements to other Neanderthal and Homo sapiens molars from southwest Asian sites. In the end, the tooth clearly belonged in a category with the Neanderthal molars.

And the Neanderthal in question seems to have been a young child, probably around 9 years old, just getting their first permanent teeth in. The first molar is usually one of the first permanent teeth to grow in, and this one showed hardly any signs of wear, which suggests that it was fairly new. So far, efforts to get ancient DNA from the tooth haven’t succeeded:

“A previous team have tried this, and the drill hole is evident on the image of the tooth, but as far as I am aware this was unsuccessful,” Blinkhorn told Ars.

In the same layer of sediment as the tooth, the archaeologists who excavated at Shukbah in 1928 found ancient hearths and stone tools. Blinkhorn and his colleagues took a closer look at those earlier archaeologists’ notes and the tools they had found, and many of them turned out to have been made in the Nubian Levallois style.

“Illustrations of the stone tool collections from Shukbah hinted at the presence of Nubian Levallois technology, so we revisited the collections to investigate further,” said Blinkhorn. “In the end, we identified many more artifacts produced using the Nubian Levallois method than we had anticipated.”

Finding fossils alongside stone tools is relatively rare, but when it happens, it links ancient hominins directly with the things they made and used. Archaeologists rely on those rare links to identify the makers of stone tools at other sites where no fossils remain. Stone tool technologies linked to a particular hominin species or culture help archaeologists track how, where, and when early humans moved through the world.

But the Shukbah Cave molar suggests it’s actually not that simple. “This study… issues a timely note of caution that there are no straightforward links between particular hominins and specific stone tool technologies,” said study co-author Simon Blockley, an archaeologist at Royal Holloway, University College of London.

Same idea, different times and places

Blinkhorn, who specializes in stone tools, told Ars that Neanderthals probably figured out the Nubian Levallois method on their own, separately from groups of H. sapiens who also invented the technology at different times and places. If he’s right, it’s similar to how human cultures around the world have independently arrived at the same solutions for other technological challenges, from pyramids to bows and arrows to fishing.

“Within Africa, there is evidence for multiple, independent innovations of Nubian Levallois technology. Its identification in southern Africa appears disconnected from its appearance in northern/eastern Africa,” Blinkhorn told Ars. “Given the common background in using other Levallois methods, the simplest explanation is that Neanderthals also separately developed Nubian Levallois methods.

Other scenarios are also possible, of course, especially given the overlapping and mingling of hominin species in the Levant at the time. As always in archaeology, additional evidence is needed to draw more detailed conclusions.

Scientific Reports, 2021 DOI:  10.1038/s41598-001-822576  (About DOIs).

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