Researchers have made a significant discovery near Lake Turkana in northern Kenya, where they unearthed fossils of hand and foot bones belonging to an extinct human relative, dating back approximately 1.52 million years. This find suggests that the species, known as Paranthropus boisei, was capable of grasping and manipulating objects, including stone tools, and was fully bipedal.
The fossils represent the first hand and foot bones that can be definitively linked to Paranthropus boisei. The excavation yielded a partial skeleton that includes most of the hand, three foot bones, significant dental remains, a partial forearm bone, and fragments of the skull. Given the incomplete nature of earlier fossils from this species, this new finding is particularly groundbreaking.
This species is part of the human evolutionary lineage and is essentially a cousin to modern humans, Homo sapiens, which evolved much later. Paranthropus boisei was characterized by a robust build, featuring strong jaws and large teeth. Its skull was adapted for heavy chewing of tough plant materials, including a distinctive crest atop the cranium that provided support for large jaw muscles, while its flaring cheekbones contributed to a dish-shaped facial structure.
Prior to this discovery, researchers had limited understanding of Paranthropus boisei due to the absence of hand and foot fossils, which made it challenging to ascertain its capabilities regarding tool-making and usage. “Sixty-five years after the original discovery of this species, this is the first time we can confidently link Paranthropus boisei to specific hand and foot bones,” stated paleoanthropologist Carrie Mongle from Stony Brook University, who is the lead author of the study published in the journal Nature.
The fossils were found in a region known as Koobi Fora, located on the eastern side of Lake Turkana. According to Louise Leakey, a paleoanthropologist and coauthor of the study, the discovery enhances understanding of the species since previous findings were primarily cranial and dental, leaving much of the skeleton unexplored.
The structure of the hand bones indicates that Paranthropus boisei could form precision grips akin to those of modern humans, suggesting its ability to create and utilize stone tools. “It would have had a very firm handshake,” Leakey noted. “The hand of this species was built for powerful and sustained grips, similar to gorillas, and was likely used for processing tough plant materials, such as stripping, tearing, or crushing vegetation, consistent with its robust dentition.”
Additionally, the foot bones provide insights into the species” locomotion, confirming that it was adapted for upright walking on two legs. “Analysis of the few foot bones shows it was fully bipedal, unlike the flat-footed chimpanzee, and its foot would have had a lateral arch similar to ours, aiding in forward propulsion during walking,” Leakey explained.
Species from the human evolutionary line are referred to as hominins. Paranthropus boisei was among four hominin species that coexisted in East Africa between approximately 1 million and 2 million years ago. Although stone and bone tools from this era have been found, it remained uncertain whether Paranthropus had the capability to create and use such tools. The genus refers to a group of closely related species that includes our own, Homo, along with extinct relatives like Homo habilis, Homo rudolfensis, and Homo erectus, which lived alongside Paranthropus boisei in East Africa.
Recent studies have indicated that Paranthropus boisei and Homo erectus left overlapping footprints at a once muddy lakeshore in Koobi Fora. This intriguing discovery raises questions about the interactions between these two species and their competition for resources. “Traditionally, it has been believed that while Homo species developed larger brains and advanced stone tools that allowed for greater adaptability to environmental changes, Paranthropus boisei specialized in a diet primarily focused on grasses,” Mongle observed.
