New Fossil Of Ancient Human Relative Shows 'Surprising' Dexterity: Stony Brook University Study

STONY BROOK, NY — A new study reveals that an "ancient human relative" could grip, and had "surprising dexterity," Stony Brook University said.

For more than half a century, scientists have debated whether Paranthropus boisei, an extinct human relative known for its extremely powerful jaws and massive teeth, could make and use stone tools, Stony Brook said.

Now, researchers report in the journal Nature the first hand and foot bones unambiguously associated with this species, Stony Brook said —their work shows that P. boisei had human-like dexterity with "gorilla-like gripping strength," a release said.

"This is the first time we can confidently link Paranthropus boisei to specific hand and foot bones," says Dr. Carrie S. Mongle, a paleoanthropologist and Assistant Professor of Anthropology at Stony Brook University, who led the study.

"The hand shows it could form precision grips similar to ours, while also retaining powerful grasping capabilities more like those of gorillas, and the foot is unquestionably adapted to walking upright on two legs."

Paranthropus is an evolutionary cousin of Homo sapiens, likely diverging from a common australopith ancestor more than 3 million years ago, researchers said.

Previously, P. boisei was known to scientists almost exclusively from fossil skulls and teeth, without much from the rest of the skeleton, especially the hands and feet. Because of that, it has been difficult for researchers to confidently infer details about their locomotor repertoire or ability to make and use stone tools, Stony Brook added.

Homo and Paranthropus fossils are sometimes found at the same fossil sites, but it has been generally assumed that any recovered stone tools at these sites should be attributed to Homo rather than Paranthropus.

The partial skeleton — designated KNM-ER 101000 — was discovered and excavated between 2019 and 2021 at Koobi Fora, on the eastern side of Lake Turkana in Kenya, from deposits dated to just over 1.5 million years ago, Stony Brook said.

"It took a huge amount of time to carefully remove the sediments that ultimately revealed these amazing fossils," Cyprian Nyete, field director of the excavations, said.

The samples included cranial fragments, teeth, and a "remarkably preserved set" of hand and foot bones, researchers said.

"There has been a long controversy about whether or not this species made and used stone tools," said Dr. Matt Tocheri, a co-author of the study from Lakehead University in Canada. "This fossil evidence effectively ends that debate."

The team’s analysis showed that although P. boisei clearly had human-like hand proportions, which would have enabled it to manipulate stone tools just as well as species of early Homo, they still lacked the specialized wrist anatomy seen in later humans and Neanderthals, researchers said.

The new discovery also sharpened debate over the ecological roles of different early hominin species. While species of early Homo appear to have evolved to be more reliant on tool use, Paranthropus likely had a very specialized diet of plant foods, based on distinctive adaptations in its face, teeth, jaws, and now, hands.

"This discovery helps us understand a lot more about Paranthropus boisei, especially how its hand shared similarities with members of our own genus Homo while evolving its own capabilities," said Dr. Caley Orr, a co-author from the University of Colorado School of Medicine. "It has converged on gorilla morphology in ways that are consistent with obtaining and processing tougher plant foods with its hands, and these powerful grasping abilities would also have been quite useful for climbing."

The research leading to the finding was supported by funding from the National Geographic Society and the Stony Brook Research Foundation.

The study was carried out by an international team of researchers from the Turkana Basin Institute, National Museums of Kenya, Koobi Fora Research Project, Stony Brook University, University of Colorado, Lakehead University, Washington University in St. Louis, Rutgers, University of Southern California, and the American Museum of Natural History.