A fossilized foot found in Ethiopia has been linked to a lesser-known human relative that lived alongside Australopithecus afarensis, famously known for Lucy. Recent research published in Nature suggests that this Burtele foot belongs to Australopithecus deyiremeda, challenging the long-held belief that Lucy was the direct ancestor of modern humans.
Researchers have discovered that A. deyiremeda and A. afarensis coexisted in the same area. Each species had unique physical traits and eating habits. This raises important questions about early human evolution and whether Lucy’s lineage directly led to us.
A Different Kind of Walker
The Burtele foot, dating back roughly 3.4 million years, contains eight bones. One striking feature is its opposable big toe, suggesting the species was skilled at climbing trees. In contrast, Lucy’s species had feet designed primarily for walking upright.
Yohannes Haile-Selassie, who led the research team, initially suspected that this fossil did not belong to A. afarensis. It wasn’t until the discovery of some teeth and a jawbone in 2015 that a connection to A. deyiremeda was established. Recent findings support this link, adding new layers to our understanding of human ancestry.
As Haile-Selassie noted, “Bipedality—walking on two legs—in these early human ancestors came in various forms.” This shows that upright walking developed through different adaptations in various species.
Different Diets, No Competition
Isotope analysis of A. deyiremeda teeth indicates it primarily fed on trees and shrubs. In contrast, Lucy’s kind ate more varied plant materials. These dietary differences suggest the two species thrived in the same environment without competing directly for resources.
Haile-Selassie emphasized, “This is the first time we’re showing that Australopithecus deyiremeda and Australopithecus afarensis were able to coexist.” Their distinct diets and movement methods allowed them to occupy different ecological niches in ancient East Africa.
A More Complex Family Tree
The discovery of A. deyiremeda further complicates our understanding of human evolution. For decades, A. afarensis was viewed as our direct ancestor. Yet, with new evidence, scientists now believe the story is more intricate.
Fred Spoor from London’s Natural History Museum highlighted that A. deyiremeda shows traits from both ancient and newer species, suggesting it may connect to multiple branches of our evolution. “The new research suggests that A. anamensis wasn’t just the ancestor of Lucy, but many other human species could descend from it as well,” he stated.
Ryan McRae from the Smithsonian cautions that we still cannot confirm whether either A. deyiremeda or A. afarensis is our ancestor. Further excavations could reveal more fossils that might reshape our understanding even more.
In summary, this fascinating new link in the human family tree encourages scientists to rethink how we view our evolution. The story of our origins is proving to be less like a straight line and more like a bushy branching tree, filled with unexpected relatives and pathways.
