Scientists say a mysterious foot fossil unearthed in northeastern Ethiopia belongs to a little-known ancient human relative, offering new insight into how multiple early hominins shared the landscape more than three million years ago.
The so-called Burtele foot was found at Burtele in 2009. Its anatomy — notably an opposable big toe capable of grasping branches — differed sharply from that of Australopithecus afarensis, the species best known from the Lucy skeleton. Because the foot retained a more chimp‑like toe, researchers long suspected it belonged to a different hominin, but they lacked direct evidence tying it to a named species.
In 2015 researchers had proposed a new species, Australopithecus deyiremeda, based on several jaw fragments from the Burtele area dated to roughly 3.4 million years ago. That assignment provoked debate because the material was limited and the association between the bones and the foot was not yet proven.
A new study reports additional fossils from the site, including a jaw with 12 teeth, which the team says confirm the Burtele foot and the dental remains belong to the same species, A. deyiremeda. Lead author Yohannes Haile‑Selassie of Arizona State University told AFP the researchers are confident the foot and the teeth come from the same hominin.
CT scans of the dental material suggest A. deyiremeda retained more primitive features than A. afarensis. Isotope analyses indicate a diet heavy in leaves, fruit and nuts from trees, consistent with a lifestyle that included substantial time in the canopy. The grasping big toe reinforces this picture: A. deyiremeda appears to have been better adapted for climbing, while the more humanlike foot of A. afarensis reflects increased commitment to ground‑based bipedal walking.
That contrast offers a solution to a long‑standing puzzle: how two different australopiths could coexist in the same place and period. The researchers argue the species partitioned ecological niches — A. deyiremeda exploiting wooded areas and arboreal foods, A. afarensis spending more time on open ground — allowing both to persist side by side.
External experts praised the new material for strengthening the case for A. deyiremeda. John McNabb, a Paleolithic archaeologist at the University of Southampton, said the additional finds and their validation of earlier specimens will likely win wider acceptance of the species and “adds a new player into the mix” when hunting for the ancestor of genus Homo.
Because A. deyiremeda appears more primitive in some respects and kept a less humanlike foot, researchers do not expect it to displace A. afarensis as the leading candidate for a direct ancestor of Homo. Instead, the discovery highlights that multiple australopith species with different adaptations coexisted, and that early hominins were experimenting with forms of bipedality.
Recent methodological advances in dating and a string of discoveries across eastern Africa continue to refine the picture of human origins. Scientists already place the emergence of Homo sapiens in Africa around 300,000 years ago and see evidence that bipedal traits arose at least six million years ago. Identifying the Burtele foot as belonging to A. deyiremeda adds complexity to that long, branching story and underscores the diversity of hominin life in our deep past.