Fossilized remains belonging to some of humanity’s oldest ancestors are much older than previously believed, according to a new study.
The fossils — including one belonging to the cavewoman known as Mrs. Ples — were buried millennia ago in South African caves known to acheologists as the Cradle of Humankind.
Modern testing methods now indicate that the group of early humans lived between 3.4 and 3.7 million years ago.
This new timeline could change the way we understand human evolution. This means that there are more possible ways our ancestors evolved to become the first humans.
For years, scientists believed that the species Australopithecus africanuswhose fossils were discovered in the Sterkfontein Caves near Johannesburg, South Africa, was less than 2.6 million years old.
The cave complex has revealed more early human remains than anywhere else in the world — including the nearly complete skull discovered in 1947 belonging to a cavewoman nicknamed Mrs. Pleas.
According to the Smithsonian Museum in Washington DC (United States), the species — which walked on two feet — were much shorter than modern humans. Males measured 1.38 meters; females, 1.15 meters.
But new radioactive dating techniques show that Mrs. Ples and the other fossils discovered around it are actually 1 million years older than previously thought.
The researchers reviewed the age of the fossils by testing sediments around them for levels of a rare isotope created when the rocks were exposed to cosmic rays — before falling into the cave.
Previously, hominids Australopithecus africanus they were considered by scientists to be too young to have evolved into the genus homo, our ancestors, who roamed the Earth around 2.2 million years ago.
These findings now suggest that they had an extra million years to make that evolutionary leap — which makes it possible for Mrs. Ples is an ancestor of the first humans.
As a result of the research, the species is now believed to have existed on Earth during the same time as the ape known as Lucy, whose 3.2-million-year-old remains belonged to Earth. Australopithecus afarensis from Africa were long considered the species that gave rise to the first humans.
The updated timeline means the two species may have interacted and even interbred, scientists say, further complicating our understanding of where humans came from. The new data suggest that the evolutionary line may not have been so simple.
The human family tree is “more like a bush,” said French scientist Laurent Bruxelles, who was part of the study.
– This text was originally published in https://www.bbc.com/portuguese/geral-61978524