A 3.4M-year-old set of foot bones from Ethiopia is forcing paleoanthropologists to redraw one of the most familiar diagrams in science, the human family tree. For decades, Lucy, the famous Australopithecus afarensis skeleton, has been cast as the central character in that story, a near singular ancestor bridging ape-like bodies and human-like walking. The new fossils suggest that, instead of a lone trailblazer, Lucy may have been only one of several closely related species experimenting with how to move, climb, and survive in a changing African landscape.
The implications are stark: if multiple hominin species lived side by side between roughly 3.8 m and 3 million years ago, then Lucy’s branch may not lead straight to us at all. Rather than a simple ladder, early human evolution starts to look like a braided river, with channels that merge, dead-end, or run in parallel for hundreds of thousands of years.
Lucy’s iconic status meets a crowded past
Lucy has long occupied a privileged place in the public imagination because her skeleton is both remarkably complete and strikingly transitional, with a small brain but hips, knees, and ankles adapted for upright walking. As an early Australopithecus afarensis individual, she seemed to stand at the base of the human line, a single, elegant solution to how an ape body could be retooled for life on the ground. Later discoveries of Additional A. afarensis fossils only reinforced that image, filling in details of her species’ anatomy and range and encouraging textbooks to present Lucy as the archetypal ancestor.
Yet even as Lucy’s bones were celebrated, researchers knew the fossil record around her was patchy and biased toward a few famous sites. Work in Ethiopia and neighboring regions has steadily revealed that the period between about 4 million and 2 million years ago was more diverse than the tidy diagrams suggested, with multiple hominin forms appearing and disappearing in different habitats. That context set the stage for the shock that would follow when a very different kind of foot emerged from sediments not far from where Lucy’s species once walked.
The Burtele Foot and a 3.4-million-year puzzle
In 2009, a team excavating near the village of Burtele in Ethiopia uncovered a partial foot that immediately stood out from the A. afarensis pattern. The specimen, now widely known as the Burtele Foot, preserved key joints and toe bones that allowed scientists to reconstruct how its owner moved. Instead of the rigid, propulsive arch seen in Lucy’s species, the Burtele Foot had a more flexible structure and a big toe that could grasp, a configuration better suited to climbing and clinging to branches than to long-distance walking on open ground.
Initial analysis placed the Burtele Foot at about 3.4-million-year in age, squarely overlapping with known A. afarensis fossils from the same region. That overlap raised an immediate question: were these simply unusual individuals of Lucy’s species, or evidence of a second hominin living alongside her? The morphology pointed to the latter, and subsequent work linked the foot to a distinct species, often referred to as Au. deyiremeda, described in a detailed Nature study that emphasized its unique combination of primitive and derived traits.
A second species in Lucy’s backyard
Later field seasons strengthened the case that the Burtele Foot did not belong to Lucy’s kind. Researchers working within just 5 kilometers of classic A. afarensis sites recovered additional 3.4-million-year-old bones that matched the Burtele morphology and showed the same grasping, tree-friendly adaptations. These Mysterious 3.4 million year-old bones, found so close to Lucy’s stomping grounds, provide the clearest evidence yet that at least two early hominin species coexisted in the same landscape, exploiting different ecological niches.
For a long time, scientists assumed that only one human relative lived around 3.8 m to 3 million years ago in the region where Lucy’s fossils were found, a tidy scenario that made A. afarensis the default ancestor. Work on the Burtele material, however, argues that another hominin with a more ape-like foot was present at the same time, a conclusion supported by a new study that ties the foot to a distinct jaw and other skeletal elements. As one synthesis of the find notes, the human relative who owned this 3-million-year-old foot likely belonged to a species that lived alongside Lucy, not as a brief visitor but as a long-term neighbor.
How a strange foot rewrites the way we walked
The Burtele Foot matters not just because it adds another name to the hominin roster, but because it shows that early human relatives were experimenting with radically different ways of moving. While Lucy’s species had a relatively stiff midfoot and an in-line big toe suited for efficient bipedalism, the Burtele anatomy retained a mobile big toe and a more curved set of bones, indicating a creature that split its time between the ground and the trees. New fossils link this strange 3.4-million-year-old foot to Aus. deyiremeda, reinforcing the idea that at least one lineage clung to a partly arboreal lifestyle even as others committed to walking, a conclusion highlighted in recent 3.4 M analyses.
Earlier work on the same Ethiopian material had already hinted at this mosaic pattern. A report on the original foot described how a fossil discovered in Ethiopia suggested that tree-dwellers lived alongside species built for walking, with the Burtele bones preserving an ape-like grasping ability in a hominin context. When I compare that to reconstructions of Lucy’s gait, which rely on pelvic and leg fossils as well as the famous Laetoli footprints, the contrast is stark: one lineage was already walking in a way that looks surprisingly modern, while another still moved through the canopy with a foot that functioned more like a climbing tool than a rigid lever.
What coexistence means for Lucy’s place in our story
Once two species are firmly established in the same time and place, the idea of Lucy as a singular, inevitable ancestor starts to crumble. A recent synthesis of the Burtele evidence argues that the foot’s structure, adapted to upright walking in a very different way, points to multiple hominin lineages exploring bipedalism rather than a single, linear progression. Some researchers have gone so far as to suggest that these new bones could dethrone Lucy as the most likely direct ancestor of Homo, framing the discovery as a turning point in how we think about our origins and noting that Scientists now see multiple adaptations in different species rather than a single path.
Other lines of evidence point in the same direction. Analyses of the Burtele Foot and the Lucy fossil together show that two early humans coexisted about 3.5 million years ago and that they did not walk alike, a conclusion underscored by work that directly compares the Burtele Foot to Lucy’s lower limbs. When I factor in the broader Ethiopian record, which includes Revolutionary fossil evidence from Ethiopia that depicts a complex landscape of hominins competing for resources, it becomes harder to defend any single species as the inevitable ancestor. Instead, as one overview of Lucy’s legacy puts it, Lucy May Not Be Our Direct Human Ancestor After All, with new finds from Ethiopia suggesting a branching, competitive evolutionary scene.
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