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Stunning fossil discovery in Ethiopia rewrites human origins

Ancient fossil teeth from Ethiopia reveal that multiple human ancestor species were sharing the landscape nearly 3 million years ago.

Date:

May 16, 2026

Source:

Arizona State University

Summary:

A stunning fossil discovery in Ethiopia shows that early Homo and a previously unknown Australopithecus species lived together around 2.6 to 2.8 million years ago. The find overturns the classic “ape-to-human” progression and paints human evolution as a crowded, branching tree with multiple species coexisting. Scientists dated the fossils using volcanic ash deposits and are now investigating what these ancient relatives ate and whether they competed for resources.

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Scientists have discovered evidence that early humans and a newly identified Australopithecus species lived side by side nearly 2.8 million years ago in Ethiopia. The find reshapes our understanding of human evolution, revealing it was far messier and more complex than once believed. Credit: Shutterstock

Fossils from Ethiopia are reshaping one of the biggest stories in human history. Instead of a neat march from ape like ancestors to modern humans, evidence from the Ledi Geraru field site points to a much messier and more fascinating reality: several human relatives may have shared the same African landscape at the same time.

An international research team studying fossils from the site found evidence that Australopithecus and the earliest known members of Homo lived in the same region between about 2.6 and 2.8 million years ago. The fossils also point to an Australopithecus species that has not been found anywhere else.

The Ledi Geraru Research Project, led by scientists at Arizona State University, has already earned a major place in human origins research. The site has produced the oldest known member of the genus Homo and the earliest known Oldowan stone tools on Earth.

The team determined that the Ledi Geraru Australopithecus teeth did not belong to Australopithecus afarensis (the famous 'Lucy'). That finding supports the view that there is still no evidence of Lucy's species surviving later than 2.95 million years ago.

"This new research shows that the image many of us have in our minds of an ape to a Neanderthal to a modern human is not correct -- evolution doesn't work like that," said ASU paleoecologist Kaye Reed. "Here we have two hominin species that are together. And human evolution is not linear, it's a bushy tree, there are life forms that go extinct."

Reed is a Research Scientist at the Institute of Human Origins and President's Professor Emerita at the School of Human Evolution and Social Change at ASU. She has helped direct the Ledi Geraru Research Project since 2002.

The Power of 13 Ancient Teeth

The key evidence came from teeth. Thirteen fossil teeth, found in ancient sediments, helped researchers identify a remarkable moment in human evolution.

Ledi Geraru was already famous before these finds. In 2013, a team led by Reed discovered a 2.8 million year old jaw from the earliest known Homo specimen. The 2025 study adds another layer to that story by describing teeth from both Homo and an unidentified species of Australopithecus.

"The new finds of Homo teeth from 2.6 -- 2.8 million year old sediments -- reported in this paper -- confirms the antiquity of our lineage," said Brian Villmoare, lead author and ASU alumnus.

"We know what the teeth and mandible of the earliest Homo look 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 location."

For now, the mysterious Australopithecus species remains unnamed. Teeth can reveal a great deal, but scientists need more fossil material before they can formally name the species and understand where it fits on the human family tree.

How Volcanoes Help Date Human Ancestors

How can researchers know that tiny fossil teeth are millions of years old?

The answer comes from volcanoes.

Ethiopia's Afar region remains an active rifting zone, shaped by tectonic forces and volcanic eruptions. Millions of years ago, eruptions spread ash across the landscape. That ash contained feldspar crystals, which scientists can date to determine when the eruptions happened, explained ASU geologist Christopher Campisano.

"We can date the eruptions that were happening on the landscape when they're deposited," said Campisano, a Research Scientist 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 interbed between those eruptions, so we can date units above and below the fossils. We are dating the volcanic ash of the eruptions that were happening while they were