Key Takeaways
- Scientists identify 3.4-million-year-old ‘Burtele Foot’ as Australopithecus deyiremeda
- This species lived alongside Lucy’s species (A. afarensis) in the same region
- The discovery proves multiple human ancestors coexisted 3.5-3.3 million years ago
- Each species had distinct walking styles and dietary preferences
Scientists have finally solved the mystery of the 3.4-million-year-old ‘Burtele Foot’ fossils discovered in Ethiopia. The research reveals these bones belonged to Australopithecus deyiremeda, a human ancestor that lived alongside the famous Lucy’s species during a crucial period in human evolution.
Two Species, One Time Period
The discovery confirms that two closely related hominin species – Australopithecus deyiremeda and Australopithecus afarensis (Lucy’s species) – coexisted in northeastern Ethiopia’s Afar region between 3.5 and 3.3 million years ago. This challenges the previous assumption of linear human evolution with only one species at a time.
“They provide us with the most conclusive evidence showing that A. afarensis – Lucy’s species – was not the only human ancestor that lived between 3.5 and 3.3 million years ago,” said lead author Yohannes Haile-Selassie of Arizona State University.
Distinct Walking Styles
The Burtele Foot showed this species walked upright but with a crucial difference – it retained an opposable big toe similar to tree-climbing apes. While Lucy’s species had a human-like big toe, A. deyiremeda probably pushed off from its second digit when walking.
“It would definitely be less efficient walking on two legs when on the ground. However, it was more effective for tree-climbing – not a bad trade-off, especially in areas where there were large predators,” Haile-Selassie explained.
Different Diaries, Different Survival Strategies
Chemical analysis of tooth enamel revealed stark dietary differences between the two species. Lucy’s species was a generalist, eating grasses along with tree and shrub foods. A. deyiremeda, however, stuck exclusively to tree and shrub-based diets.
“These species were moving around in different ways. There were multiple ways to be human at this time,” said co-author Naomi Levin from the University of Michigan. “We can now associate these different ways of moving around on two feet with different diets.”
Solving the Coexistence Puzzle
The research raises intriguing questions about how these close relatives shared resources without direct competition. Their different locomotion styles and dietary preferences may have allowed them to coexist in the same environment.
“Now that we know they ate different things and that they moved around in different ways, we’re that much closer to solving this puzzle of co-existence,” Levin concluded. The study published in Nature represents a major breakthrough in understanding the complex branching of before Homo sapiens emerged.
