A paper published in Nature describes a partial skeleton, KNM-ER 101000, recovered on the eastern shore of Lake Turkana, Kenya. The 42 fossils, dated to roughly 1.5 million years ago, include the first unambiguous hand bones of Paranthropus boisei. Researchers reported that the species’ hand combined a long, powerful thumb, short fingers and a mobile fifth digit, features that gave it both strength and precision comparable to the grips of modern humans and African apes.
The fossils came from excavation campaigns led by paleoanthropologist Louise Leakey between 2019 and 2021. Within a few metres on eroded slopes, the team uncovered foot bones, teeth, and cranial fragments that bore a prominent sagittal crest, identifying the individual as male. Computed-tomography scans showed a three-rooted fourth premolar—an anatomical trait unique to Paranthropus.
Paranthropus boisei lived in eastern Africa from about 2.6 million to 1.3 million years ago, overlapping with early Homo species. The discovery deepened the debate over which hominins fashioned the stone artefacts found in the same sediments. “Unfortunately, in these localities with multiple species, without the hominin dying with the stone tool in its hand, we can’t say for sure which hominin made it. We can now say that both would have been capable,” said Carrie Mongle, anthropologist at Stony Brook University, according to IFLScience.
Muscle-attachment scars on the fifth metacarpal and the robust thumb suggested a power grip comparable to that of someone wielding a modern hammer. “Everything related to the hand of Paranthropus boisei points to a great capacity for grasping—whether it be leafy vegetation, tools, rocks or branches—in a way unique among known hominid fossils,” said Tracy Kivell of the Max Planck Institute for Evolutionary Anthropology, according to Nature.
The associated foot, with short toes and a transverse arch, indicated habitual bipedality while the strong fingers could have facilitated climbing. “This is the first time that Paranthropus boisei can be securely linked to specific hand and foot bones,” said Mongle, according to Nature.
Some elements looked so much like gorilla bones that they could have been misidentified in isolation. “Tools have existed for at least 3.3 million years, and this hand dates back 1.5 million years,” said Samar Syeda of the American Museum of Natural History, adding that the species probably had the ability to use—if not make—tools, even though none lay beside the fossils.
Paranthropus boisei’s enormous molars earned it the nickname Nutcracker Man; wear patterns showed intensive grinding of hard plants. Mongle’s group proposed that the species’ powerful hands helped strip tough vegetation, aligning manual ability with its dietary focus.
“They’ve got a power grip and could probably hit one stone against another in a fashion to make certain types of tools,” said Andy Herries of La Trobe University, according to ABC News Australia. Michael Petraglia of Griffith University, who reviewed the study, agreed that the hand morphology indicated potential tool use despite the absence of artefacts at the site.
The find underscored the branching nature of human evolution. “One of the most coveted pieces of the evolutionary puzzle,” said paleoanthropologist Almudena Estalrrich, praising the new post-cranial evidence that may help assign ownerless phalanges from earlier digs.
“I would love to use CT scans to study the internal structure of these bones to learn more about how exactly Paranthropus boisei was using its hands,” said Mongle, according to ABC News Australia.
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