Although scientists have uncovered much of the story of human evolution, several key chapters are still missing. One major gap lies between 2 and 3 million years ago, a period for which fossil evidence remains scarce. This absence is especially significant because it marks the era when the branch of the hominin family tree that includes modern humans, or Homo sapiens, first appears in the fossil record.

Today, Homo sapiens (commonly referred to by anthropologists as Homo) is the only surviving member of the hominin lineage. In earlier times, however, our ancestors shared the Earth with other related species, sometimes competing and coexisting with them. Recent research supported by the National Science Foundation and the Leakey Foundation, and published in Nature, helps close one of these evolutionary gaps by revealing two early hominin species that lived side by side.

At the Ledi-Geraru site in Ethiopia’s Afar Region, an international research team discovered hominin fossils dated between 2.6 and 3.0 million years old. Lucas Delezene, an associate professor of anthropology at the University of Arkansas, served as the study’s second author, contributing alongside more than 20 scientists from North America, Africa, and Europe.

The findings include fossils of Homo that establish the oldest confirmed evidence of our lineage at 2.8 million years ago, with additional remains dating to 2.6 million years ago. These discoveries strengthen the case for Homo’s deep evolutionary roots. Even more surprising, the team found that Homo lived in the same region at the same time as another hominin, Australopithecus, around 2.6 million years ago.

This overlap challenges long-held assumptions, as Australopithecus was believed to have vanished from the area roughly 3 million years ago. The famous Australopithecus specimen known as Lucy was discovered nearby, yet her species was thought to have disappeared from the fossil record by that point.