Evidence that first toolmakers predated the genus Homo

Discover reports: Thanks to a wrong turn, a stroke of luck and keen eyes, husband and wife research partners Sonia Harmand and Jason Lewis of Stony Brook University could rewrite our understanding of tool use among hominins. With their team from the West Turkana Archaeological Project, the pair have found evidence that a species predating the genus Homo may have made the first stone tools.

In July 2011, Harmand and Lewis and their colleagues were scouting for sites in the area around northern Kenya’s Lake Turkana. There are no roads in this remote region, so Harmand was forced to drive in dry creek beds while Lewis navigated with a GPS device. It’s all too easy to become disoriented in this kind of terrain; at a certain juncture where the GPS indicated a right turn, she mistakenly went left. They soon found the way blocked by bushes. Unable to drive farther, they climbed a small hill to get their bearings. From the top of the rise, the team gazed down on what Harmand describes as a uniquely beautiful landscape.

“I felt certain it contained hidden areas waiting to be explored,” she says. Everyone fanned out to investigate. “We were only 10 people, working far from each other with walkie-talkies. Around 9 in the morning, we had a call from our local Turkana team member, Sammy Lokorodi. He said, ‘You should come where I am because I think I’ve spotted something very interesting.’ ”

He found stone tools sticking out of an eroding creek bed. The surface above had a dark, weathered patina, but the areas around the rocks were light, suggesting they had been only recently exposed. Harmand knew at once this was an important find because the layers in which the tools were embedded were dated to more than 2.7 million years old.

Paleomagnetic dating — matching magnetic properties in the sediments surrounding a fossil or artifact to ancient reversals in the Earth’s magnetic poles to determine age — later determined the tools had to have been made 3.3 million years ago. Despite the tools’ simple form and huge size, some almost 8 inches across, the angle and patterns on the rocks’ edges showed repetitive strikes that could not have resulted from erosion or other natural processes. Publishing the discovery in Nature in May, Harmand and Lewis dubbed the assemblage the Lomekwi 3, after the area where the tools were found. [Continue reading…]

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