The fossils discovered in the northeast of Ethiopia, dating between 2.6 and 2.8 million years, provide new information on the course of human evolution.
An international team of researchers has discovered new fossils in Africa showing that Australopithecus And the first known members of Homo lived in the same region at the same time, between 2.6 and 2.8 million years. Among the discoveries, there was a stranger before species of Australopithecus, unlike any identified before.
The discoveries come from the LEDI-Geraru research project, led by scientists from Arizona State University. This site has already produced the oldest known homo specimen in the world, as well as the first examples of Oldowan Stone tools.
Detailed study of the new Australopithecus The teeth have confirmed that they represent a distinct species rather than belonging to Australopithecus AfarensisThe species of the famous fossil “Lucy”. This finding strengthens that none are the line of Lucy is known to have less than 2.95 million years.
“This new research shows that the image that many of us have in our mind a monkey to a Neanderthal to a modern human is not correct – the evolution does not work like that,” said the Paleoecologist of the Asu, Kaye Reed. “Here, we have two species of hominines that are together. And human evolution is not linear, it is a bushy tree, there are forms of life that disappear.”
A research effort extending over decades
Reed is a researcher at the Institute of Human Origins and is the professor of emeritus president at the school of human evolution and social change at Arizona State University. She has also co-produced the Ledi-Geraru research project since 2002.
So what fossils have helped shape these new conclusions? The team discovered 13 teeth in total.
The Ledi-Geraru site has already drawn attention. In 2013, Reed and his colleagues reported the discovery of the first known homo fossil – a jaw dating from 2.8 million years. The new study is based on this inheritance, describing additional teeth of the site which belong to both homo gender and a newly identified species of Australopithecus.
“New homo teeth discoveries from 2.6 to 2.8 million old sediments, reported in this article, confirm the antiquity of our line,” said Brian Villmoare, principal author and former ASU student.
“We know what the teeth and the mandible of the first homo look like, but that’s it.
The team cannot yet name the species according to the teeth alone; More fossils are needed before it can happen.
How do scientists know that these fossil teeth have millions of years?
Volcanoes.
The Afar region remains an active rift area, marked by a frequent volcanic and tectonic activity. When these volcanoes broke out, they released ashes containing crystals called feldspaths, which provide scientists with a way to determine their age, said Christopher Campisano, ASU geologist.
“We can go out with the eruptions that were happening on the landscape when they are deposited,” said Campisano, a researcher at the Institute of Human Origins and Associate Professor at the School of Human Evolution and Social Change.
“And we know that these fossils are prohibited between these eruptions, so we can go out with units above and below the fossils. We go out with the volcanic ashes of the eruptions which were happening while they were in the landscape.”
The ancient landscape of Ledi-Geraru
Finding fossils and a landscape dating help not only scientists understand the species, but this also helps them to recreate the environment millions of years ago. The modern rocket badlands of Ledi-Geraru, where the fossils were found, contrasting the landscape that these hominines crossed 2.6 to 2.8 million years ago. At the time, rivers migrated through a vegetated landscape in shallow lakes that have extended and contracted over time.
Ramon Arrowsmith, asu geologist, has been working with the LEDI-Gerau research project since 2002. He explained that the region has an interpretable geological file with good age control for the geological range of 2.3 to 2.95 million years.
“This is a critical period for human evolution, as this new article shows,” said Arrowsmith, professor at the Earth School and Spatial Exploration. “Geology gives us the age and the characteristics of the sedimentary deposits containing the fossils. It is essential for age control. ”
Reed said that the team now examined teeth enamel to discover what it can on what these species ate. There are still questions on which the team will continue to work.
Did the first homo and this unidentified Australopithecus species ate the same things? Did they fight or shared resources? Have they passed daily? Who were the ancestors of these species?
No one knows – yet.
“Whenever you have an exciting discovery, if you are a paleontologist, you always know that you need more information,” said Reed. “You need more fossils. This is why this is an important area to train people and so that people go out and find their own sites and find places where we have not yet found fossils. ”
“More fossils will help us tell the story of what happened to our ancestors a long time ago – but because we are the survivors, we know that it happened to us.”
Reference: New discoveries of Australopithecus and Homo by Ledi-Geru, Ethiopia. Dominique I. Gary, Mohammed Ahmedin Hayidara, Helsh M. Nature.
Two: 10.1038 / S41586-025-09390-4
Financing: US National Science Foundation
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