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Find Suggests Human Tool Use Began Earlier

Carol Ward knows bones.

As a professor of pathology and anatomical sciences at the University of Missouri, she has dedicated much of her work to the study of human and ape fossils, participating in active field research from Croatia to East Africa.

So in April 2011, when her research team sent back a plastic replica of their most recent finding — a small hand bone discovered in the Lake Turkana area in northern Kenya — she immediately realized its significance.

“As soon as I looked at it,” Ward said, “I knew.”

This month, nearly three years after it was discovered, the 1.42 million-year-old middle metacarpal bone serves as the crux of a scientific study suggesting that humans’ ability to use complex tools originated more than 500,000 years earlier than previously believed.

The study’s findings, published in the Proceedings of the National Academy of Sciences, have shed new light not only on the evolution of man, but on one of his most vital features.

The anatomy of the third metacarpal bone, which connects the middle finger to the wrist, is a defining human characteristic. It features the styloid process, allowing us to grip everything from a crowbar to a smartphone, while differentiating us from the plethora of other species.

“We can do things with our hand that no animal on the planet can,” said Ward, who served as the study’s lead author. “The way we can hold objects, we can grip things between our thumbs and fingers, a very strong pinch grip, very powerfully. Imagine if you’re making a stone tool — that’s what you need to be able to do.”

Although it had long been known that modern Homo sapiens possessed such an ability, it had been unclear when in the evolution process the distinctive, humanlike anatomy of the hand originally appeared, said Ward.

According to the findings, the bone probably belonged to a member of Homo erectus, a species that predated Homo sapiens.

For Ward, the discovery represented a nominal moment in a career that has spanned three decades.

Ward’s foray into the world of fossils began early in college, when she enrolled in a biological anthropology course at the University of Michigan.

“I wanted to take the weirdest class I could,” she explained.

Within a few years, she had earned a Ph.D. in functional anatomy and evolution at Johns Hopkins in Baltimore. In 1991, she joined the faculty at the University of Missouri, where she eventually became part of the West Turkana Paleo Project.

Before the group’s 2011 discovery became public, however, it was subject to a fairly intense review process.

Ward traveled to the Cleveland Museum of Natural History and to the Smithsonian. She and a team of international researchers conferred with other experts, including Erik Trinkaus at Washington University in St. Louis and Wes Niewoehner at California State University, San Bernardino. The findings were also reviewed by a panel of peers in the field.

Since the study’s release, the discovery has sparked an understandable stir in the science world and national media. At home, where Ward has three teenage sons, the hubbub has centered on the study’s inclusion on a popular social media site.

“They’re excited that I made it on Reddit,” Ward said. “That was the biggest thing for them.”

But while the recent feedback has been nice, Ward said, plenty of other bones are currently awaiting her attention.

“We’ve got more fossils to move on to,” she said. “I’m sitting in my lab, collecting data for another paper right now.”