Paris (AFP) - In 1974, anthropologists in Ethiopia found the astonishing fossilised remains of a human-like creature who last walked the planet some 3.2 million years ago.
Was "Lucy," as the hominid was called, the direct ancestor of Homo sapiens? Was she "The Mother of Mankind," as some headlines claimed?
Over the years, the dramatic assertion has come under attack by doubters, who point to ancient yet inconclusive finds in Kenya and Chad.
But a new fossil, reported on Wednesday, may have dealt Lucy's claimed status an irreversible blow.
Another species of hominid lived at the same time and in the same Afar region of Ethiopia, according to the paper, published in the journal Nature.
Named Australopithecus deyiremeda, the hominid and Lucy are probably only part of a wider group of candidates for being our direct forerunners, the finders said.
"The new species is yet another confirmation that Lucy's species, Australopithecus afarensis, was not the only potential human ancestor species that roamed in what is now the Afar," said Yohannes Haile-Selassie of the Cleveland Museum of Natural History.
"Current fossil evidence... clearly shows that there were at least two, if not three, early human species living at the same time and in close geographic proximity."
The find, in the Woranso-Mille area of the Afar region, comprises fossilised remains of an upper and lower jaw, dated to a range of 3.3-3.5 million years ago.
This overlaps with the range given to Lucy, of 2.9-3.8 million years ago.
The bones are clearly different from Lucy's, with teeth of different size, shape and enamel thickness and a more robust lower jaw, said the study.
They were found in March 2011 on top of silty clay in the Burtele area, about 500 kilometres (325 miles) northeast of Addis Ababa and 35 km north of Hadar, where Lucy was found.
The estimated age is derived from radioactive dating of the soil and "paleomagnetic" data, which traces changes in Earth's magnetic field, recorded in iron-bearing sediment, as a calendar.
The name "deyiremeda" means "close relative" in the language of the Afar people.
- Heated debate -
Understanding the human odyssey has always been a fraught business, complicated by the rarity of fossil finds and sometimes fierce squabbles about where -- or even if -- they should be placed in the family tree.
The same team had previously found the 3.4-million-year remains of a foot in the same region, but were unable to assign the fossil to a particular hominid species.
"Some of our colleagues are going to be skeptical about this new species, which is not unusual," Haile-Selassie admitted.
"However, I think it is time that we look into the earlier phases of our evolution with an open mind and carefully examine the currently available fossil evidence rather than immediately dismissing the fossils that do not fit our long-held hypotheses."
Only a week earlier, anthropologists shook the coveted position held by Homo habilis, the hominid deemed to have come before Homo sapiens.
Habilis -- "handy man" in Latin -- has traditionally been enshrined as a benchmark of hominid smartness, endowed with a bigger brain and greater dexterity than his predecessors.
But earlier hominids may have had some of his skills, if the May 20 study is right.
It reported finding the world's oldest stone tools in northwestern Kenya.
The implements date back to around 3.3 million years ago, which is some 500,000 years before Habilis emerged and 700,000 years before the first known Habilis tools.