This overlooked human ancestor wielded tools with a gorilla-like grip

When it comes to our evolutionary cousins, Neanderthals get most of the attention. Part of this is understandable, since there was a time in Earth’s history when the role of dominant primate was up for grabs. Tweak any number of environmental factors, and the tool-wielding, yarn-weaving Homo neanderthalensis may have outlasted its Homo sapien cousins (aka humans) instead of going extinct around 40,000 years ago.

Regardless, the focus on Neanderthals often ignores the dozens of other ancient hominin species that existed for hundreds of thousands of years in various parts of the planet. Homo erectus, for example, may have been some of our first relatives to migrate into Europe, while Homo bodoensis evolved a distinctive, three-part segmented brow.

Now, one of our lesser known ancestors is getting some spotlight. Recent analysis of fossilized remains in Kenya ostensibly proves that Paranthropis boisei was fully capable of crafting and using their own tools. The evidence is detailed in a study published on October 15 in the journal Nature.

The Paranthropus genus likely diverged from one of our shared australopith ancestors over three million years ago. However, evidence of the species that went extinct about 1.8 million years later has largely been limited to fossilized skulls and teeth. Due to this lack of fossil evidence,  experts have had trouble speculating about the rest of its anatomy. While teams have found both Homo and Paranthropus remains scattered across the same sites around South Africa, Tanzania, and Ethiopia, researchers often assumed that any accompanying stone tools must have belonged to the latter group.

Now, skeletal fragments discovered between 2019 and 2021 on the eastern side of Kenya’s Lake Turkana are rewriting P. boisei’s story. In this case, the specimen dates to around 1.5 million years old, and includes the first known hand and foot bones directly linked to the hominins. Paleoanthropologists already knew that P. boisei featured powerful jaws and sizable teeth, but the recent excavations further illustrate the species’ physicality. While these relatives possessed human-like hand proportions, their grip strength more likely resembled one of today’s great apes.

“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,” study co-author Carrie Mongle and Stony Brook University anthropologist explained in a statement.

Mongle and her colleagues also noted that although P. boisei could manipulate stone tools as well as early Homo species, they lacked a more specialized wrist structure seen in humans and Neanderthals. Part of this may be due their different ecological roles. Early Homo species evolved over time to be more reliant on tools, but Paranthropus anatomy suggests their specialized, plant-based diet lessened this need.

“‘[P. boisei] 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,” said Caley Orr, a study co-author and developmental biologist at the Colorado University Anschutz School of Medicine.

According to collaborator Louise Leakey, the revised understanding of P. boisei is part of an “exciting new era in paleoanthropology.” She would know firsthand—her own (much closer) relatives have strong ties to the early human ancestors, as well.

“[The field] has changed and grown so much since my grandparents discovered the first skull of Paranthropus boisei at Olduvai, and my parents first began to focus their research on the fossil-rich Turkana Basin in Kenya,” she said.

 

Shop Amazon’s Prime Day sale

We’ve hand-picked dozens of PopSci-approved deals on tools, electronics, and more. Grab them before they’re gone.