Fossils from Ethiopia are reshaping one of the greatest stories in human history. Rather than a neat journey from ape-like ancestors to modern humans, the evidence from the Lady Geraru Field Site points to a much messier and more fascinating reality: many human relatives may have shared the same African landscape at the same time.
An international research team studying fossils from the site found evidence of australopithecus and earliest known member Homosexual Lived in this area about 2.6 to 2.8 million years ago. The fossils also point to an Australopithecus species that has not been found anywhere else.
The Lady Geraru Research Project, led by scientists at Arizona State University, has already earned a prominent place in human origins research. The site has produced the oldest known members of the genus Homo and the earliest known Oldowan stone tools on Earth.
The team determined that the teeth of Lady Geraru did not belong to Australopithecus australopithecus afarensis (The famous ‘Lucy’). This discovery supports the view that there is still no evidence of Lucy’s species surviving 2.95 million years ago.
“This new research shows that the image many of us have of everything from apes to Neanderthals to modern humans is not true – evolution just doesn’t work that way,” said ASU paleontologist Kay Reed. “Here we have two hominin species that coexist. And human evolution is not linear, it’s a shrubbery, there are life forms that go extinct.”
Reed is a research scientist at the Institute of Human Origins and Presidential Professor Emerita in the School of Human Evolution and Social Change at ASU. He has helped direct the Lady Geraru Research Project since 2002.
13 The Power of Ancient Teeth
The main evidence came from teeth. Thirteen fossilized teeth found in ancient sediments helped researchers identify a remarkable moment in human evolution.
Lady Geraru was already famous before these discoveries. In 2013, a team led by Reed discovered the earliest known 2.8-million-year-old jawbone Homosexual Sample. The 2025 study adds another layer to that story by describing the teeth of both Homosexual and an unknown species australopithecus.
“The new discovery of Homo teeth from sediments 2.6 – 2.8 million years old – reported in this paper – confirms the antiquity of our lineage,” said lead author and ASU alumnus Brian Willmore.
“We know what the teeth and mandible of early Homo looked like, but that’s it. This emphasizes the critical importance of finding additional fossils to understand the differences between Australopithecus and Homo, and potentially how they were able to overlap in the fossil record at the same locations.”
At the moment, the name of the mysterious Australopithecus species is unknown. Teeth can tell a lot, but more fossil material is needed before scientists can formally name the species and understand where it fits on the human family tree.
How volcanoes help date human ancestors
How do researchers know that tiny fossil teeth are millions of years old?
The answer to this comes from volcanoes.
Ethiopia’s Afar Region remains an active rift zone, created by tectonic forces and volcanic eruptions. Millions of years ago, eruptions spread ash across the landscape. ASU geologist Christopher Campisano said the ash contained feldspar crystals, based on which scientists could determine when the eruption occurred.
“We can date eruptions on the landscape when they were deposited,” said Campisano, a research scientist at the Institute of Human Origins and associate professor in the School of Human Evolution and Social Change.
“And we know that these fossils are buried in between those eruptions, so we can date the units above and below the fossils. We’re dating the volcanic ash from those eruptions that was occurring at the time they were on the landscape.”
That volcanic timeline tells scientists much more than age estimates. It also helps them reconstruct the world in which these ancient hominins lived.
A very different Ethiopia
Today, the Lady Geraru area is a rugged landscape of faulted wasteland. But between 2.6 and 2.8 million years ago, it looked very different. Ancient rivers traversed a lush environment, feeding shallow lakes that grew and shrank over time.
By studying the sediments around fossils, researchers can reconstruct where habitats once existed. Homosexual And australopithecus Use to live. This matters because environment can help explain how many hominin lineages survived at the same time.
Ramon Arrowsmith, a geologist at ASU, has worked with the Lady Geraru Research Project since 2002. He said the area preserves a readable geologic record with strong age controls for deposits dating back to about 2.3 to 2.95 million years ago.
“As this new paper shows, this is a crucial time period for human evolution,” said Professor Arrowsmith from the School of Earth and Space Exploration. “Geology tells us the age and characteristics of sedimentary deposits containing fossils. This is essential for age control.”
human evolution was not a straight line
Lady Geraru’s findings add to a growing picture of early human evolution as a crowded, branching story. 2025 Nature study report Homosexual Fossils date back between 2.78 and 2.59 million years, with australopithecus 2.63 million years ago. It also states that at least four hominin lineages lived in East Africa between 3.0 and 2.5 million years ago: Early Homosexual, paranthropus, A GarhiAnd Lady Geraru Australopithecus.
Since the publication of the Lady Geraru paper in 2025, that picture has become even more interesting. In 2026, a team led by the University of Chicago Said to be 2.6 million years old paranthropus jaw From the Afar region of Ethiopia. That discovery placed another hominin lineage in a wider area during the same critical window and suggested that early human relatives were more widespread and ecologically flexible than previously thought.
Overall, these discoveries point far from a simple ladder of progress. Instead, early human evolution looks like a landscape full of overlapping experiments, some of which went nowhere, while one ultimately led us.
What did these ancient relatives eat?
Reed said the team is now studying tooth enamel to learn more about what this species eats. Diet may help answer one of the biggest mysteries raised by fossils: how things started in the beginning Homosexual and this unknown australopithecus Share the same space?
Were they eating the same food? Did they compete for the same resources? Did they avoid each other, or did they cross paths often? Were they part of a larger network of hominin species that lived in East Africa?
No one knows yet.
“Whenever you have an exciting discovery, if you’re a paleontologist, you always know you need more information,” Reed said. “You need more fossils. That’s why this is an important area to train people and to have people go out and find their own sites and find places where we haven’t found fossils yet.”
“More fossils will help us tell the story of what happened to our ancestors a long time ago – but because we are survivors, we know it happened to us.”
A major clue from a missing chapter
The paper “New discoveries of Australopithecus and Homo from Ledi-Geraru, Ethiopia” was published Nature In 2025. The research team included scientists and field researchers from multiple institutions, many of whom were associated with Arizona State University as faculty members or alumni.
ASU alumni and current faculty authors include Associate Professor Brian Willmore, Associate Professor Lucas Delezine, Professor Amy Rector, Associate Research Professor Erin DiMaggio, Research Professor David Fieri, PhD candidate Daniel Chupik, Instructor Dominic Garello, Assistant Professor Alice M. Locke, Lecturer Joshua Robinson, Assistant Professor Irene Smail, and the late Professor William Kimbell.
Fossils don’t provide every answer. They do something equally important: They show that the story of human origins was more crowded, more contested, and more unpredictable than the familiar textbook version. Somewhere in that ancient mix of species, landscapes, diets, and serendipitous events, the path of modern humans began to take shape.