Analysis of the skull recovered nearly two decades ago has shed new light on the life of our ancient ancestors. The 7-million-year-old skull, scientists conclude, belongs to a creature who walked upright, and new evidence hints that they did that on two legs instead of on all fours.
The findings mark an important phase of evolution in the human story.
Researchers analysed the arm and leg fossils found near the skull in Africa as they looked for signs of two feet making it the oldest known human ancestor, by a long shot, that walked. They are nearly a million years older than other early known hominins. The study published in the journal Nature states that while they walked on foot, they could also climb trees like apes, which was an important part of their lives.
Researchers initially looked at the fossil creature’s skull, teeth, and jaw and argued that the creature must have walked on two feet and held its head upright, based on the location of the hole in the skull where the spinal cord connects to the brain. While others did not agree, they went on digging for more evidence.
Researchers at the University of Poitiers in France then turned to a thighbone that had been left unstudied. They found the bone in the lab’s collection and realized it probably belonged to a fossil species. Compared to bones from other species, the thighbone matched up better with upright-walking humans than knuckle-walking apes, according to the study.
“There is not one feature. There is just a total pattern of features,” they said after analysis at a press briefing.
Another researcher at the French university, Roberto Macchiarelli, had previously examined the thighbone and determined the species was probably an ape. Looking at the new study, Macchiarelli told The Associated Press that he still doesn’t believe the species was a hominin, though it might have walked on two legs at times.
While it will need more research to conclusively establish the earliest moment when our ancestors began walking, this is the one small step in the right direction.
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