PARIS - A short, hairy "ape man" who tumbled into a pit in South Africa millions of years ago is back in the running as a candidate ancestor for humans, scientists said Friday.
A painstaking 13-year probe has "convincingly shown", they said, that the strange-looking creature named Little Foot lived some three million years ago -- almost a million years earlier than calculated by rival teams.
If so, it would make Little Foot -- so named for the diminutive size of the bones -- one of the oldest members of the Australopithecus hominid family ever found.
And it would bolster the status of South Africa's Sterkfontein cave complex as part of the "Cradle of Humankind", a UN-recognised World Heritage Site.
"Some have said South Africa is too young" to have given rise to modern man, said Laurent Bruxelles from France's National Institute for Archaeological Research (Inrap), who took part in the study.
"We are putting Little Foot and South Africa back in the running."
Another challenger for the title of human ancestor was "Lucy," a specimen of a different strand of Australopithecus -- the genus that had both ape and human features, walked upright, and is believed to have given rise to Homo sapiens, or anatomically modern Man, via Homo habilis.
Lucy's skeleton, uncovered in Ethiopia in 1974, has been dated to about three million years, although as always in fossils, there is a big margin of uncertainty.
"No longer are the Australopithecus of East Africa, like Lucy, the sole candidates" to have been our ancestors, said Bruxelles.
Little Foot's age has been a controversial topic.
The Sterkfontein caves, northwest of Johannesburg, do not contain volcanic sediment, as do the east African fossil sites, which is easier to date.
This has caused estimates of Little Foot's age to fluctuate quite drastically -- anything from 1.5 to 4.0 million years, though the most extreme estimates have long been ruled out.
Little Foot's skeleton is the most complete of an Australopithecus ever found.
This file photo taken on May 21, 2005, shows fossils on display at Maropeng in South Africa. PHOTO/AFP
In 2006, a paper in the journal Science estimated its age at 2.2 million years, based on chemical dating of the layers of stone around the fossil.
Now Bruxelles and a team of French and South African scientists said calcite deposits dubbed "flowstones" that enveloped Little Foot were much younger than the fossil itself.
"The dated flowstones filled voids formed by ancient erosion and collapse," said a statement from the University of the Witwatersrand.
"The skeleton is therefore older, probably considerably older, than the dated flowstones."
Barely a metre tall, Little Foot fell into a 20-metre (66-foot) hole and died, possibly while running from a predator.
The body rolled down a steep slope and came to land with its left arm stretched out over its head.
Over the years, the remains, naturally mummified, were buried under more than 10 metres of sediment and rock, until they were uncovered in 1997.
The discovery of Little Foot was met with great excitement -- estimated at first to be about 3.3 million years old, it would have been a contemporary of Lucy.
But the later, younger, dating threatened Little Foot's place in the human evolutionary picture.
"There is a lot at stake here," said Bruxelles.
"Homo habilis appeared about 2.5 million years ago, which means that Little Foot could not have been our ancestor if it lived later than that."
Robert Cliff, a member of the team that authored the 2006 Science study, told AFP there was no reason to doubt the age of the rocks they measured.
But, he added: "The fact that what we dated was not the fossil itself, may leave open the possibility that the relationship between our (stone) samples and the fossil was more complicated than we thought at the time."
Far older fossils of hominids have been found in East Africa and Chad that predate the known rise of Australopithecus, but their lineage, if any, to our ancestors remains unclear.
The new study appears in a specialist publication, the Journal of Human Evolution.