Mysterious owner of 3-million-year-old foot found in Africa identified, scientists say

Newly discovered fossils show that a mysterious foot found in Ethiopia belongs to a little-known and recently named ancient human relative that lived alongside the famous Lucy’s species, scientists said Wednesday.

The discovery is the latest twist in the story of human evolution and could even cast some doubt on the status of Lucy’s species, Australopithecus afarensis, as a direct ancestor of Homo sapiens.

Until the foot was discovered in Burtele, northeastern Ethiopia, in 2009, Lucy’s species was thought to be the only human relative that lived in the area more than three million years ago.

But the appendage clearly does not belong to Lucy’s species because it has an opposable, thumb-like finger that allows its owner to grab onto tree branches like they were apes.

The team of scientists who found the mysterious foot went on to name a new species, Australopithecus deyiremeda, in 2015 based on some approximately 3.4 million-year-old jaw bones found at Burtele.

The announcement was met with some skepticism in scientific circles. Due to the scarcity of fossils, attempts to add a new branch to the human family tree often provoke intense debate.

The team also couldn’t say that the foot bones, called Burtele’s foot, belonged to their new species.

Now, in a study published Tuesday titled “Mysterious owner of African hominid foot identified,” scientists announced that new fossils, including a jaw with 12 teeth found at the site, show the foot was that of A. deyiremeda.

“We have no doubt that Burtele’s foot belongs to the same species as these teeth and the jaw,” the study’s lead author, Yohannes Haile-Selassie, of Arizona State University, told News.

The research also revealed more details about this species, offering more clues as to who the true ancestor of Homo sapiens might have been.

“Coexistence is deeply rooted in our ancestry”

A CT scan of the teeth suggested that A. deyiremeda was more primitive than its cousin Lucy, according to the study.

Meanwhile, isotopic analysis of the teeth showed that their diet consisted mainly of tree leaves, fruits and nuts.

The big toe also suggested that this human relative spent more time in trees. Big toes played an important role in human evolution, allowing our ancestors to leave the trees behind and walk on two legs.

An outstanding question about A. deyiremeda was how it could have coexisted with Lucy’s species at the same place and time, Haile-Selassie said.

The new research suggests that the former spent his time in the forest, probably eating from the trees, while the latter spent more time on the ground, a difference that allowed them to live together.

This also shows that “coexistence is deeply rooted in our ancestry,” Haile-Selassie stressed.

Earlier this year, in the same region where Lucy was discovered, archaeologists found 3 billion year old knives believed to have been some of the first tools used on Earth. Rick Potts, director of the Smithsonian’s human origins program and leader of the peninsula research, told News themezone that the discovery may help frame the existence of humans on the planet.

“We’re the last bipeds standing, as I call it,” Potts said. “All those other forms of life became extinct. And that gives us a lot to think about and draws attention to the fragility of life, even in our own journey through time.”

New technologies have made it easier to date sites, and new discoveries in East Africa have refined researchers’ understanding of human roots. Researchers knew that modern Homo sapiens emerged in Africa about 300,000 years ago, but it wasn’t until recently that they understood that their hominid ancestors began walking on two legs at least 6 million years ago.

Search for the identity of our true ancestor

John McNabb, a paleolithic archaeologist at the University of Southampton in the United Kingdom who was not involved in the study, praised the new research.

“There will always be skeptics, but I think these new findings and the validation of older ones will help many researchers better accept A. deyiremeda,” he told News.

It also “adds a new player to the mix” in the search for the identity of our true ancestor, McNabb added.

Given that A. deyiremeda was more primitive and had a less human-like foot than Lucy, it is unlikely to dethrone her as the prime suspect in this search, both scientists agreed.

But the discovery “opens up the possibility that we could still find more species in that period because it appears that australopithecines were experimenting with bipedality,” or walking on two legs, Haile-Selassie said.

“Could there be another species that is a better candidate to be the ancestor of the genus Homo?” asked.

“We don’t know, it depends on what we find.”