Researchers from the Wits University found evidence that the Taung Child, a fossilized skull unearthed in South Africa in 1924, did not undergo the same cranial development as modern humans did.
The Australopithecus africanus fossil was estimated to be about 2.8 million years old. Scientists initially thought the three-year-old child was killed by an eagle because of the puncture marks in its eye sockets, as well as the presence of eggshells at the site where it was discovered.
Study author Dr. Kristian J. Carlson from the Evolutionary Studies Institute of the University of Witwatersrand worked with his colleagues to dissect the fossil using high-resolution computed tomography, or CT scan. The researchers looked at the skull of the Taung Child and observed that the child did not undergo the same development in the prefrontal region, unlike the modern humans. They also compared it to the chimpanzees and saw no resemblance.
For decades, the Taung Child has been considered an important artifact because it is the best model that can reveal a hominin's brain evolution.
"A recent study has described the roughly 3 million-year-old fossil, thought to have belonged to a 3 to 4-year-old, as having a persistent metopic suture and open anterior fontanelle, two features that facilitate post-natal brain growth in human infants when their disappearance is delayed," Carlson explained.
The researchers added that the dissimilarity of the features of the Taung Child's skull to those of a modern human can be used for further study of the evolution of later hominins, especially the australopiths. This species is believed to be the longest-lived and best-known early human species.
The study concluded that there is still no scientific evidence that will explain how the modern humans' brains evolved, particularly on the prefrontal lobe.
Further details of the study were published in the Aug. 26 issue of Proceedings of the National Academy of Sciences.