X

Study finds early human ancestor lacked nutcracker jaws

The species, Australopithecus Sediba, is thought to be part of the ancestry of Homo, which is the group our species belongs to. Researchers could dig in and take a closer look at this ancient hominid in this recent study.

“Most australopiths had amazing adaptations in their jaws, teeth and faces that allowed them to process foods that were difficult to chew or crack open,” said David Strait, a researcher of the study. “Among other things, they were able to efficiently bite down on foods with very high forces.”

The fossilized skull of Australopithecus sediba specimen MH1 and a finite element model of its cranium depicting strains experienced during a simulated bite on its premolars. “Warm” colors indicate regions of high strain, “cool” colors indicate regions of low strain. Credit: Washington University in St. Louis/MH1 by Brett Eloff, courtesy of Lee Berger and University of the Witwatersrand.

The journal Nature Communications published these findings on February 8, in which it describes a biomechanical testing of a computer-based model of an Australopithecus sediba skull. Researchers used biomechanical methods in the making of the study, similar to those used by engineers to test the endurance of vehicles.

These findings show how vast our species really is, and how researchers still have a difficult task ahead of them. The new species resemblance the Homo species in very few traits of their physiology, yet Australopithecus’ jaw shows a clear distinction on the era these specimens lived in.

It appears as if the new specimen could only compare to the Homo species in the ability to walk upright on two legs. The Australopithecus fossil dates back for about four million years ago, and apparently most of them lacked some human features like a large brain; flat faces with small jaws and teeth, and advanced tool-use.

Justin Ledogar, Ph.D., a researcher from the University of New England in Australia explained, “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. This means that whereas some astralopith populations were evolving adaptations to maximize their ability to bite powerfully, others were evolving in the opposite direction,” Ledogar said in the study.

David Strait, who is also a paleoanthropologist and writher of ecological adaptations and evolutionary relationships of early humans, agrees with Ledogar. He says Ledogar’s study provides a good example of how engineering tools can be used in order to answer these evolutionary questions.

“Our study provides a really nice demonstration of the difference between reconstructing the behaviors of extinct animals and understanding their adaptations.” Strait said. “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 before they died. This tells us 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,” later added researcher David Strait.

Source: Washington University in St. Louis

Categories: Science
Daniel Contreras:
Related Post