MELBOURNE, Dec. 15 (Xinhua) -- An international study has challenged the long-held classification of one of the world's most complete ancient human fossils, raising the possibility of an unknown human ancestor.
The fossil, found in South Africa's Sterkfontein Caves in 1998 and dubbed "Little Foot," has been widely believed to be a member of the Australopithecus genus, either A. africanus or A. prometheus, a lineage of ape-like upright walkers that lived in South Africa between 3 million and 1.95 million years ago, a media release of Australia's La Trobe University said Monday.
But a peer-reviewed article published in the American Journal of Biological Anthropology 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, it said.
"This fossil remains one of the most important discoveries in the hominin record and its true identity is key to understanding our evolutionary past," said study lead author Jesse Martin of La Trobe University and the University of Cambridge in Britain.
Martin's team has become the first since Little Foot's 2017 unveiling to challenge the fossil's species classification. The skeleton, formally known as StW 573, remains the most complete ancient hominin ever found and could reshape views of human evolution in southern Africa.
"This is more likely a previously unidentified, human relative," Martin said, highlighting the need for further careful, evidence-based taxonomy in human evolution.
"It is clearly different from the type specimen of A. prometheus, which was a name defined on the idea these early humans made fire, which we now know they didn't," said Professor Andy Herries at La Trobe.
The study was conducted under an Australian Research Council grant directed by Herries, and involved scientists from Australia, South Africa, Britain and the United States.
Students from La Trobe University will now work to clarify which species Little Foot represents and where that species sits in the human family tree, the release said. ■