Ancient Human Ancestor Evolved Teeth That Couldn't Crack Nuts Open

Contrary to earlier findings, a new study suggests that Australopithecus sediba did not have teeth and jaws of a nutcracker. The study sheds important light on human evolution as A. sediba is a strong contender to the distinction of modern man's australopith ancestor.

The study is based on bio-mechanical computer modeling of an A. sediba skull recovered from South Africa in 2008. According to UPI, researchers at Washington University in St. Louis found that biting down very hard could have dislocated the hominid's jaw. Past research had suggested that the species subsisted on a diet that included bark and shelled nuts. The new findings suggest that the facial structure, jaw and teeth of A.sediba could not have allowed for such a diet.

"Examination of the microscopic damage on the surfaces of the teeth of A. sediba has led to the conclusion that the two individuals known from this species must have eaten hard foods shortly before they died. This gives us information about their feeding behavior," said team leader David Strait.

"Yet, an ability to bite powerfully is needed in order to eat hard foods like nuts or seeds. This tells us that even though A. sediba may have been able to eat some hard foods, it is very unlikely to have been adapted to eat hard foods."

The findings assume significance as A. sediba is a pre-human species that is thought to have eventually led to arrival of the homo genus.

"Humans also have this limitation on biting forcefully and we suspect that early Homo had it as well, yet the other australopiths that we have examined are not nearly as limited in this regard," first author of the study Justin Ledogar said adding that australopith populations were evolving in opposite directions.