Paul John Myburgh/ Witts University
-The skeleton of Little Foot, discovered in the 1990s in a cave in South Africa.
Not Australopithecus prometheusno A. africanus. “We believe that this is a hitherto unknown and unstudied human ancestral species”, says a new research team about the famous “Little Foot”.
The fossil known worldwide as “Little Foot” (“Little Foot”), one of the most complete hominin skeletons ever found, may ultimately belong to a species that was previously unknown.
The conclusion is from a new study, in American Journal of Biological Anthropologywhich reignites the debate about the diversity of our ancestors and the very structure of the human evolutionary tree.
to the world in 2017, “Little Foot” is described as the skeleton of Australopithecus most complete known. The foot bones that gave the specimen its name were discovered in 1994 in South Africa, and a long excavation began from the feet: work that lasted for around 20 years in the Sterkfontein cave system, one of the most emblematic places for the study of human evolution.
O Pulao Isentoroo Ronald Clarkefrom the University of the Witwatersrand, led the team responsible for recovering the skeleton and argued that the fossil should be attributed to Australopithecus prometheus. Other researchers have pointed to Australopithecus africanusa species first described in 1925 and also identified in Sterkfontein.
But the new research separates both theories. Australian scientists concluded that “Little Foot” presents characteristics that do not fit well with either of these two species, paving the way for a third hypothesis: the existence of a lineage not yet sampled in the fossil record.
“We believe that this is a hitherto unknown and unstudied human ancestral species,” he said. Jesse Martinassociate professor at La Trobe University, who led the investigation.
For the author, the discovery could mean not just a new “point” in the human family tree, but an entire branch yet to be mapped. “It doesn’t look like Australopithecus prometheus… but it also doesn’t look like all the Australopithecus africanus found at Sterkfontein,” he says.
Jesse Martin holding the mysterious “Little Foot” skull.
“This fossil remains one of the most important discoveries in the hominid record and its true identity is fundamental to understanding our evolutionary past,” said Martin, from La Trobe University.
The team highlights decisive differences at the base of the skull, including a longer nuchal plane, the area at the lower back of the skull. Martin emphasizes that this region tends to be relatively conservative throughout evolution, so variations observed there are more compatible with the distinction between species than with simple variation within it.
Despite the results, the authors do not propose a formal reclassification of the fossil: any new designation should be made by the team that excavated and studied it for more than two decades, the team argues.
The study also appears in a context of disagreement about the age of “Little Foot”: some dating points to 3.67 million years, while other scientists argue that the specimen cannot be older than 2.8 million years.
Despite the disagreements, one thing is certain. Little Foot, known formally as StW 573, remains the most complete ancient hominin in the fossil record and one of the most fascinating finds ever. The mystery deepens.
