A legendary fossil is forcing scientists to rethink human origins
One of the most complete human ancestor fossils ever found may belong to an entirely new species, according to an international research team. The famous “Little Foot” skeleton from South Africa has long been debated, but new analysis suggests it doesn’t truly match any known Australopithecus species. Instead, researchers say its unique mix of features points to a previously unidentified human relative, reshaping ideas about early human diversity.
An international research team led by scientists from La Trobe University in Australia and the University of Cambridge is questioning how one of the most complete early human fossils has been classified. Their findings suggest the specimen may not belong to any known human ancestor species and could represent an entirely new one.
The fossil, uncovered in South Africa's Sterkfontein Caves in 1998 and nicknamed "Little Foot," has long been considered part of the Australopithecus genus. This group includes early, upright-walking relatives of humans that lived in southern Africa between about 3 million and 1.95 million years ago.
Ronald Clarke, the paleoanthropologist who led the painstaking 20-year effort to excavate and study the skeleton, initially identified Little Foot as Australopithecus prometheus when it was formally introduced in 2017. Other researchers argued it belonged to Australopithecus africanus, a species first described in 1925 by Australian anatomist Raymond Dart and already known from the same region.
New Evidence Challenges Old Assumptions
In a peer-reviewed study published in the American Journal of Biological Anthropology, a team led by La Trobe University adjunct Dr. Jesse Martin reached a different conclusion. Their analysis found that Little Foot does not share a distinct combination of features with either Australopithecus prometheus or Australopithecus africanus. This opens the door to the possibility that the fossil represents a previously unrecognized species.
"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 A.prometheus or A. 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."
Why Little Foot Matters
Formally known as StW 573, Little Foot is still considered the most complete ancient hominin skeleton ever found. Despite its significance, no team had publicly challenged its species classification since its debut in 2017 until now.
"Our findings challenge the current classification of Little Foot and highlight the need for further careful, evidence-based taxonomy in human evolution," Dr. Martin said.
Dr. Martin, who holds an adjunct position at La Trobe University and is a postdoctoral research fellow at Cambridge, will continue this work alongside La Trobe students. Their goal is to determine exactly which species Little Foot belongs to and where it fits within the broader human family tree.