An article published in the journal “Scientific Reports” reports a study on the characteristics of the skull of the specimen of Australopithecus nicknamed “Little Foot” that offers information on this species’ life. A team of researchers from Wits University led by Dr Amélie Beaudet examined a 3D reproduction of the fossil generated by subjecting it to a high resolution micro-CT scan. The presence of the first cervical vertebra has a crucial role in the biology of vertebrates and the Little Foot’s one is in its place offering information on the possible head movements for this species of Australopithecus, different from those possible for modern humans.
The almost complete specimen of Australopithecus cataloged as Stw 573 and nicknamed Little Foot was excavated between 1994 and 1998 in the Sterkfontein caves in South Africa. Paleoanthropologist Ronald J. Clarke was examining fossils found at that site when he recognized some bones of a left foot that showed characteristics that indicated that they belonged to a hominin. Their small size earned the specimen its nickname. Subsequently, Clarke found other bones of the same individual and, after a long and patient work, he and his colleagues obtained an almost complete skeleton.
The dating of Little Foot was problematic due to the nature of the site where the skeleton was found. Over the years various datings were made which provided very different results. A new technique based on radioisotopes provided results reported in the journal “Nature” in April 2015 which shows that indicate that it’s 3.67 million years old.
Another problem about Little Foot concerns the attribution to a species. The characteristics are similar to those of other specimens of the genus Australopithecus but according to Ronald J. Clarke and some other paleontologists it could be a different species from the ones already known, and the name Australopithecus prometheus was proposed.
The image (Courtesy Ronald J. Clarke. All rights reserved) shows two views of Little Foot’s skull. The inferior view also allows to see the first cervical vertebra, indicated by the arrow.
Modern technologies are becoming increasingly important in the field of paleontology and the possibility of subjecting Little Foot’s skull to a high resolution micro-CAT scan made it possible to create a 3D reproduction of it.
In December 2018 similarities and differences between the brain of that species of Australopithecus and that of modern humans studied thanks to that reproduction were reported in the “Journal of Human Evolution”. A team composed of almost the same researchers continued to study Little Foot’s skull and the brain as well in this new research.
The examination of Little Foot’s skull and cervical vertebra indicate that it was capable of head movements other than those possible for modern humans. According to the researchers, that’s connected to that species’ ability to climb trees and move in them. A South African Australopithecus specimen that is about a million years younger may have partially lost that ability and spent more time on the ground.
The traces of blood flow to Little Foot’s brain are well preserved and allow to estimate that its use of glucose was about a third compared to modern humans and close to that of chimpanzees. According to the researchers, the vascular system of humans, with its ability to feed a much larger brain and therefore with a need for much more energy, emerged far later.
The exact attribution of Little Foot is still under discussion, therefore the relationships with other Australopithecus species are not yet clear. This means that at the moment we don’t know if Little Foot’s species is an ancestor of modern humans or a relative. It’s still a very interesting specimen to study for the information it can provide on the early stages of the evolution of hominins.