For decades, the question of whether Paranthropus boisei, an ancient human relative, could use stone tools has been debated among scientists. A new study published in Nature presents the first hand and foot bones clearly linked to this species, revealing that P. boisei had a combination of human-like dexterity and gorilla-like grip strength.
“This is the first time we can confidently link Paranthropus boisei to specific hand and foot bones,” said 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 considered an evolutionary cousin of Homo sapiens, diverging from a common ancestor over three million years ago. Until now, most fossil evidence for P. boisei consisted of skulls and teeth, with little information about its hands and feet. This gap made it difficult to assess whether the species was capable of making or using tools.
Fossils of Homo and Paranthropus are often found at the same sites, but stone tools discovered in these locations have typically been attributed to Homo species.
The partial skeleton, known as KNM-ER 101000, was excavated between 2019 and 2021 at Koobi Fora, near Lake Turkana in Kenya, from deposits dated to just over 1.5 million years ago.
“It took a huge amount of time to carefully remove the sediments that ultimately revealed these amazing fossils,” said Cyprian Nyete, field director of the excavations. The remains included cranial fragments, teeth, and well-preserved hand and foot bones.
“There has been a long controversy about whether or not this species made and used stone tools,” said Matt Tocheri, a co-author of the study from Lakehead University in Canada. “This fossil evidence effectively ends that debate.”
The research team found that while P. boisei had hand proportions suitable for manipulating stone tools, it lacked the specialized wrist anatomy found in later humans and Neanderthals.
The findings also contribute to discussions about the ecological roles of early hominin species. Early Homo species seem to have become more dependent on tool use, while Paranthropus likely maintained a specialized plant-based diet, as indicated by features 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 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,” he explains, “and these powerful grasping abilities would also have been quite useful for climbing.”
Louise Leakey, director of the Koobi Fora Research Project, highlighted the collaborative nature of the work: “Overall, this discovery is a great example of how much we can achieve when we undertake long-term fieldwork that involves strong collaborations between researchers from around the world and the local communities that live in the places where hominin fossils are preserved.”
Leakey added, “None of this would be possible if it weren’t for the dedication and commitment of our local community partners, who spend seven to eight months a year exploring, surveying, and excavating this area. It is definitely an exciting new era in paleoanthropology, which has changed and grown so much since my grandparents [Louis and Mary Leakey] discovered the first skull of Paranthropus boisei at Olduvai and my parents [Richard and Meave Leakey] first began to focus their research on the fossil-rich Turkana Basin in Kenya.”
The research was supported by funding from the National Geographic Society and the Stony Brook Research Foundation.
An international team from several institutions, including Stony Brook University, Turkana Basin Institute, National Museums of Kenya, Koobi Fora Research Project, University of Colorado, Lakehead University, Washington University in St. Louis, Rutgers, University of Southern California, and the American Museum of Natural History contributed to the study.
