Little Foot fossil scanned at Diamond gets a virtual facelift

Researchers have unveiled a new digital reconstruction of the face of Little Foot, the 3.67-million-year-old Australopithecus fossil, offering fresh insight into the evolution and diversity of early human ancestors across Africa. The reconstruction reveals unexpected similarities with Ethiopian specimens, contributing to debates on early hominin relationships.  

Credit: Amelie Beaudet/Wits University

The findings, published in Comptes Rendus Palevol, draw on high-resolution synchrotron scanning carried out at Diamond Light Source, where scientists used the powerful capabilities of the I12 beamline to image the fossil in unprecedented detail. Combined with advanced virtual reconstruction techniques, the work has produced one of the most complete and informative Australopithecus faces known to date. 

Little Foot was discovered in the Sterkfontein Caves, around 40 km north-west of Johannesburg. The specimen represents the most complete early hominin skeleton ever found. However, while much of the skeleton has been extensively studied, the skull, and particularly the face, has been heavily distorted by millions of years of geological pressure, making accurate physical reconstruction impossible. 

Using synchrotron X-ray micro-computed tomography on the I12 beamline, the team captured high-resolution internal and external structural data from the fossil without causing damage. The resulting scans enabled researchers to digitally separate, realign and virtually reassemble the facial bones, correcting deformation that occurred during fossilisation.

The international research team was led by Dr Amélie Beaudet and Professor Dominic Stratford of the University of the Witwatersrand (Wits University). Through digital reconstruction, they were able to restore the facial architecture and undertake detailed comparative analyses. 

“This pattern is unexpected, given the geographic origin of Little Foot and suggests a more dynamic evolutionary history than previously assumed,” Beaudet said, a previous postdoctoral fellow and current honorary researcher at Wits University. 

The findings suggest that Little Foot may represent a lineage closely related to East African populations, while later South African hominins developed more distinct facial characteristics through local evolutionary processes. 

The team analysed nine linear facial measurements and applied three-dimensional geometric morphometric techniques to compare Little Foot with several extant great apes and three other Australopithecus fossils, including a younger South African specimen and two fossils from Ethiopia. 

Their results reveal that the overall facial size, eye socket shape and general facial architecture of Little Foot more closely resemble the East African fossils than the younger South African specimen. Given Little Foot’s South African origin, this pattern was unexpected. 

The study also identified potential selective pressures acting on the orbital region. Changes in this part of the face may reflect adaptations linked to visual capacity and ecological behaviour. 

“Besides the fact that our study, limited to one anatomical region and a couple of comparative fossil specimens, provides additional data on the affinities between Australopithecus populations across Africa, we demonstrate that the orbital part of the face has possibly been under evolutionary pressure at that time,” Beaudet said. 

The hominin face evolved over time to become less projected and more gracile, but the timing and mechanisms driving these changes remain unclear. The current study contributes important data toward answering these longstanding questions. 

The face plays a central role in how primates interact with their physical and social environments, integrating digestive, respiratory, visual, olfactory and communicative functions. As such, it provides a critical anatomical region for understanding how early hominins adapted to their surroundings. 

“Only a handful of Australopithecus fossils preserve an almost complete face, making Little Foot a rare and valuable reference point. Little Foot’s face preserves key anatomical regions involved in vision, breathing and feeding, and its skull will offer further key elements for understanding our evolutionary history,” Beaudet said. 

As further virtual reconstructions are completed, researchers hope to refine their understanding of how early hominins moved, interacted and diversified across Africa. 

“The face is only part of the story,” said Beaudet. “Other parts of the skull, especially the braincase, remain distorted by plastic deformation and will require similar digital reconstruction to better understand brain size and organisation in this early hominin.” 

The study highlights the unique capabilities of Diamond’s I12 beamline for imaging large and complex fossils non-destructively, demonstrating once again how advanced synchrotron techniques are helping to unlock some of the deepest chapters of human evolutionary history.