Mysterious Fossil Foot Belonged to Ancient Human that Lived Alongside ‘Lucy’

Mysterious fossil foot belonged to an ancient man who lived near Lucy

TO Umberto Basilio edited by Claire Cameron

Sixteen years ago group of anthropologists discovered 3.4 million year old fossilized foot bones in Ethiopia. Although they suspected the foot belonged to an ancient human who likely lived near the species we know as “Lucy,” Australopithecus afarensiswithout a skull and teeth to analyze, they could not be sure.

What they did know was that unlike Lucy, who walked upright on curved feet like ours, the mysterious foot had a grasping toe adapted for climbing trees.

Now the same team that discovered the strange leg has finally solved the mystery. In an article published Wednesday in Natureresearchers describe other hominin fossils found in the same area like an appendage they called Burtele's foot. The results confirm that Lucy lived alongside another species of hominin called I don't say Australopithecuswho behaved completely differently than him A. peers.

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“This is a really exciting discovery and a welcome one for all of us who have been wondering what this crazy leg is,” says University of Missouri anthropologist Carol Ward, who was not involved in the new study.

“Not only do we have different species living in the same place at the same time, but they also navigate the world differently,” she says.

Anthropologists had suspect that Burtele's leg belonged A. I don't say for many years: in 2015, they reported the existence of the species in the region based on jaw bones dating back 3.5 to 3.3 million years. But to finally tie A. I don't say to the foot of Burtele, the team had to return to the discovery site to find more fossils.

“We have been visiting this site every year for 20 years, and the Burtele site is visited every year, like every other site on the site,” says Arizona State University paleobiologist and study co-author Johannes Haile-Selassie.

During a recent visit to the Woranso Mille paleoanthropological site in Ethiopia, the team made several important discoveries: fragments of pelvic bones and, most importantly, a skull and jawbone with 12 teeth. Identified as belonging A. I don't say judging by the shape of the fangs and molars, the jaw had more primitive features than its A. cousins.

After analyzing the teeth, the team discovered that their owner ate a different diet than Lucy, preferring to eat trees, shrubs, fruits and leaves—a diet more similar to that of more ancient hominins, according to the team. In contrast, Lucy species typically fed on vegetation from mixed woodlands and grassland plants.

Burtele's foot provides clues as to how A. I don't say it was able to deftly climb trees in search of food: its long, curved toes and flexible bones suggest that the foot is well adapted for climbing and staying on trees. Even the bones of the big toe are thin and curved, suggesting that it can grasp branches.

Combining their findings—teeth, dietary analysis, and the foot—and taking into account the lack of other hominid fossils at the site, the scientists concluded that Burtele's mysterious foot belonged to A. I don't say.

Haile-Selassie said the discovery gives researchers more insight into how early humans adapted to walking upright. And, he says, this shows that not all human ancestors walked on two legs.

“This is a unique mode of transportation that has been subjected to various experiments throughout human evolution, right up to the advent of homo“, he says.

It could also help settle another controversy once and for all: the 2015 opening. A. I don't say has been disputed, with some scientists arguing that the specimens actually belonged to A.says paleoanthropologist Donald Carl Johanson, who discovered Lucy in 1974.

Instead, new research suggests that A. I don't say Inherited the features of his legs from an ancestral species different from the one that gave rise to Lucy's species, Johanson says. “The adoption of a new hominin species is always met with criticism,” he says. “Will the new evidence convince a wider audience that A. I don't say whether this is a valid species remains to be seen.”

Knowing that another ape lived alongside Lucy's species also challenges the idea that human evolution was relatively linear, Ward said. The new findings also raise questions about how ancient hominins walked.

Haile-Selassie's team will continue to return annually to the Burtele site to learn more about the biology and geographical distribution A. I don't say. “We can ask a lot of questions about this species,” says Haile-Selassie.

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