The 2-million-year-old jaw of possibly one of our earliest ancestors, could tell us more about our evolution, according to a new study.
For the new study – published Monday (Jan. 8) in the journal Nature Communications – the researchers examined the jaw structure and bite of Australopithecus sediba. The results suggest that the small species may have shared some of the same diet preferences as Homo sapiens (modern humans), researchers said.
About 3.5 to four million years ago, Australopiths first emerged in Africa. Experts say that Australopithecus sediba dates back to two million years ago. The first remains of A. sediba were discovered in 2008, in South Africa. The species had humanlike hands and it likely moved around using a combination of climbing trees and walking on two legs.
David Strait, co-author of the study and an anthropology professor at Washington University in St. Louis, said that most australopiths had the ability to eat foods that were difficult to crack open or chew, and they also used very high forces to bite down on foods, thanks to their teeth, jaws, and faces.
However, A. sediba seemed to be quite different from other members of its genus. New evidence suggests that A. sediba did not have as many jaw adaptations as other australopiths, according to researchers.
Australopithecus and Homo are actually both members of the Hominini tribe, which also includes the the Pan genus – nowadays made of bonobos and chimpanzees, scientists say.
Justin Ledogar, a study co-author and researcher at the University of New England in Australia, said that the early Homo probably also had limitations on biting powerfully, much like modern humans have. Instead of maximising their ability to have a forceful bite – like most australopiths – A. sediba (as well as others) were evolving in the opposite direction, Ledogar explained.
Eventually, some of these species gave rise to Homo, according to Strait. A key role in the origin of Homo was played by diets and feeding behaviours in australopiths, he noted.
To map stresses and strains during force simulations, the researchers used a computer model of the Australopithecus sediba skull that was discovered in 2008. The results showed that A. sediba was probably not adapted to eat hard foods.
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