Brain Week: 100 years ago, the discovery of the “Taung child”

This year, science celebrates the 100th anniversary of the discovery of the skull of the “Taung Child,” found in a quarry in South Africa in 1924 and described in 1925 by Australian anthropologist Raymond A. Dart. The fossil of the young child was the first evidence of a new species at that time. Australopithecus africanus, constituting an important stage in paleontology.

Since its discovery, methodological innovations have allowed for new approaches, such as the use of X-ray tomography, which was presented at the inaugural evening of Brain Awareness Week on Monday, March 3, 2025, at Paris City Hall. This global event, returning for its 27th edition, is an opportunity to recall the methods and research that revolve around this fascinating organ.

Microtomography to study missing brains

The brain, being a soft tissue, does not generally fossilize. But the brain and the skull grow very closely together over the course of an individual's life, so that in some groups, particularly mammals, the brain leaves its imprint inside the skull. Paleontologists rely on this fairly faithful image to reconstruct the shape and structure of the brains of extinct animals called endocrania.

Endocranias can be natural, when the skull fills with sediment that solidifies over time, forming an internal cast of the cranium from the outer surface of the brain. Artificial endocranias, on the other hand, are made by researchers when the cranium is free of any sediment. Because these methods are destructive, neuropaleontologists now use X-ray microtomography.

By scanning the skull, they reconstruct a virtual cast of the brain. The process, similar to medical imaging in a hospital setting, involves an X-ray source, a detector, and rotation of the fossil. The scanner takes 360-degree density measurements around the fossil, which are then used to create virtual slices. Each slice represents the density of the material at a given point. By assembling these slices, a 3D model of the inner surface of the skull is obtained, which has the same shape as the outer surface of the brain.

Three 3D models of Australopithecus endocraniums (in blue) from South Africa derived from microtomography. Credits: Beaudet, A., de Jager, E., Tawane, M., & Billings, B.

Read alsoThe first humans left Africa earlier than previously thought, nearly 2 million years ago

"The Child of Taung" is still being talked about

The discovery of the "Taung Child" revolutionized paleontology. While the skull bone was lost, the natural endocranium was found. At the time, it was the oldest ever found for the human lineage, the first tangible evidence of its African origins, and the type specimen of a new genus and species of hominid named Australopithecus africanus.

Of high quality, it preserves fine details of brain organization, such as sulci, and has opened major debates on how the human brain evolved. We could clearly see the inside of other fossils, but here, since the vault was not preserved, the discussions focused on what was present, the endocranium., relates to Science and Future Antoine Balzeau, researcher at the Natural History of Prehistoric Man laboratory of the National Museum of Natural History (MNHN-CNRS).

A century later, this endocranium still holds secrets, notably the position of a groove delimiting the primary visual cortex, a key element in tracing the evolutionary history of the human lineage.Even today, no study has been able to resolve the issue and many scientists believe that it is impossible to identify the structure in question with certainty.”, adds paleoanthropologist Amélie Beaudet, CNRS researcher at the PALEVOPRIM laboratory at the University of Poitiers.

Read alsoThe children of paranthropes, the closest relatives of humans, grew at a surprising speed

“Taung’s Child” keeps the debate on the reliability of the endocranium alive.Caution must be exercised in anatomical determinations, many errors have been made”, warns the paleoanthropologist. A study published in November 2023 in the Journal of Anatomy explores the limits of analyzing the shape and organization of the endocranium. Antoine Balzeau, lead author of the study, will give a lecture on March 12, 2025 conference at the Musée de l’Homme as part of Brain Awareness Week to discuss these topics.

If the endocranium is currently the best way to study extinct brains, “We must continue to improve our knowledge of the link between the brain and the endocranium so as not to tell too many lies.”. A point of view highlighted by Amélie Beaudet in an article published in February 2025 in the journal South African Journal of Science and during the inaugural conference of Brain Awareness Week 2025.