An international research team has concluded that the famous Little Foot fossil from South Africa may represent a previously unidentified human relative. The nearly complete skeleton, discovered in 1998, does not match known Australopithecus species, prompting a reevaluation of early human evolution. This finding highlights the complexity of hominin diversity in ancient southern Africa.
The Little Foot skeleton, formally known as StW 573, was unearthed in South Africa's Sterkfontein Caves in 1998. Nicknamed for its small foot bones, it is regarded as the most complete ancient hominin skeleton discovered to date. Paleoanthropologist Ronald Clarke led a 20-year effort to excavate and study it, formally identifying it as Australopithecus prometheus in 2017. However, other experts proposed it belonged to Australopithecus africanus, a species described in 1925 from the same region.
A new peer-reviewed study, published in the American Journal of Biological Anthropology in 2025, challenges these classifications. Led by Dr. Jesse Martin, an adjunct at La Trobe University in Australia and postdoctoral researcher at the University of Cambridge, the analysis reveals that Little Foot lacks the distinct features shared with either A. prometheus or A. africanus. "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 stated. He added, "We think it's demonstrably not the case that it's A. prometheus or A. africanus. This is more likely a previously unidentified human relative."
The research supports Clarke's earlier view of two hominin species at Sterkfontein. Dr. Martin credited Clarke, noting, "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."
Funded by an Australian Research Council grant under Professor Andy Herries at La Trobe University, the study involved collaborators from the United Kingdom, Australia, South Africa, and the United States. Professor Herries emphasized its differences: "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."
Australopithecus species, upright-walking relatives of humans, inhabited southern Africa from about 3 million to 1.95 million years ago. This work underscores the need for precise taxonomy to map human evolutionary history and adaptations to ancient environments.