New research led by scientists from the University of Cambridge and Latrobe University challenges the classification of the Little Foot fossil as Australopithecus prometheus.
The Little Foot fossil in the Sterkfontein cave, central South Africa. Image credit: Purdue University.
The Little Foot fossil was discovered in 1994 in a cave at Sterkfontein in central South Africa.
Also known as StW 573, the specimen was named for four small foot bones found in a box of animal fossils that led to the skeleton’s discovery.
In the 2010s, paleoanthropologist Ronald Clarke attributed Little Foot to a species of hominin called Australopithecus prometheus.
Others maintained it was Australopithecus africanus, a hominin species first described by Australian anatomist Raymond Dart in 1925 and which was already known from the same site and South Africa more broadly.
But in the new study, La Trobe University researcher Dr. Jesse Martin and colleagues found that Little Foot does not share a unique suite of traits with either species, raising the possibility that it may represent a new species altogether.
“This fossil remains one of the most important discoveries in the hominin record and its true identity is key to understanding our evolutionary past,”Dr. Martin said.
“We think it’s demonstrably not the case that it’s Australopithecus prometheus or Australopithecus africanus. This is more likely a previously unidentified, human relative.”
“Dr. Clarke deserves credit for the discovery of Little Foot, and being one of the only people to maintain there were two species of hominin at Sterkfontein.”
“Little Foot demonstrates in all likelihood he’s right about that. There are two species.”
Forensic facial reconstruction of another Australopithecus species – A. afarensis. Image credit: Cicero Moraes / CC BY-SA 3.0.
The authors now plan to clarify which species Little Foot represents and where that species sits in the human family tree.
“Little Foot was one of the most complete and important fossils ever discovered in terms of what it could tell us about early human diversity and how our ancestors adapted to the different environments of southern Africa,” said Professor Andy Herries, a researcher at Latrobe University and the University of Johannesburg.
“It is clearly different from the type specimen of Australopithecus prometheus, which was a name defined on the idea these early humans made fire, which we now know they didn’t.”
“Its importance and difference to other contemporary fossils clearly show the need for defining it as its own unique species.”
The research is described in a paper published in the December 2025 issue of the American Journal of Biological Anthropology.
_____
Jesse M. Martin et al. 2025. The StW 573 Little Foot Fossil Should Not Be Attributed to Australopithecus prometheus. American Journal of Biological Anthropology 188 (4): e70177; doi: 10.1002/ajpa.70177
