New 2.6-million-year-old Paranthropus fossil reshapes understanding of early hominins

In a new paper published in Nature, a team led by University of Chicago paleoanthropologist Professor Zeresenay Alemseged reports the discovery of the first Paranthropus specimen from the Afar region of Ethiopia, 1000 km north of the genus’ previous northernmost occurrence. This finding offers significant new information about when and where Paranthropus existed, its adaptation to diverse environmental conditions, and how it may have interacted with other ancient relatives of modern humans including our genus Homo.

“If we are to understand our own evolutionary trajectory as a genus and species, we need to understand the environmental, ecological, and competitive factors that shaped our evolution,” said Alemseged, the Donald N. Pritzker Professor of Organismal Biology and Anatomy at UChicago. “This discovery is so much more than a simple snapshot of Paranthropus’ occurrence: It sheds fresh light on the driving forces behind the evolution of the genus.”

Paranthropus previously “missing” among hominins in the Afar and northeast Africa

Since the human and chimpanzee lineages diverged around 7 million years ago, human ancestors went through a dramatic evolutionary process that ultimately led to the emergence of Homo sapiens around 300,000 years ago.

“We strive to understand who we are and how we became to be human, and that has implications for how we behave and how we are going to impact the environment around us, and how that, in turn, is going to impact us,” Alemseged said.

In the fossil record, the human lineage is represented by over 15 hominin species that generally fit into four groups:

1. Facultative bipeds, e.g. Ardipithecus — Occasionally bipedal but mostly living in trees and walking on all four limbs.
2. Habitual bipeds: Australopithecus — Retained arboreality to some degree but mostly practiced upright walking and experimented with stone tools.
3. Obligate bipeds: Homo — The genus to which modern humans belong, characterized by a larger brain, sophisticated tools and obligate bipedalism.
4. Robust hominins: Paranthropus (also known as robust australopithecines) — Habitually bipedal like Australopithecus but distinguished by extremely large molars capped by thick enamel and facial and muscular configurations that suggest a powerful chewing apparatus.

Alemseged said: “Hundreds of fossils representing over a dozen species of Ardipithecus, Australopithecus, and Homo had been found in the Afar region of northern Ethiopia, so the apparent absence of Paranthropus was conspicuous and puzzling to paleoanthropologists, many of whom had concluded the genus simply never ventured that far north.”

He added, “While some experts suggested that dietary specialization restricted Paranthropus to southern regions, others hypothesized that this could have been the result of Paranthropus’ inability to compete with the more versatile Homo.” However, Alemseged said, “neither was the case: Paranthropus was as widespread and versatile as Homo and the new find shows that its absence in the Afar was an artifact of the fossil record.”

Rethinking hominin biogeography, adaptation, and competition

The 2.6-million-year-old partial jaw reported in Nature comes from the Mille-Logya research area in the Afar and is one of the oldest Paranthropus specimens unearthed to date. After recovering as many fragments as possible from the field site, the team brought them back to Chicago to analyze internal anatomy and morphology with powerful micro-CT scanning.

“It’s a remarkable nexus: an ultra-modern technology being applied to a 2.6-million-year-old fossil to tell a story that is common to us all,” Alemseged said.

This new find shows that Paranthropus was as widespread and versatile as Homo and was not necessarily outcompeted by Homo.

Paranthropus was previously nicknamed the “nutcracker” genus, highlighting the very large molars, thick enamel, and heavy jaws and reflecting assumptions that this chewing apparatus caused Paranthropus to occupy a highly specialized and narrower dietary niche. But the new Paranthropus from Afar reveals that starting from its earliest origins, Paranthropus was widespread, versatile, and able to crack more than just nuts.

“The new discovery gives us insight into the competitive edges that each group had, the type of diet they were consuming, the type of muscular and skeletal adaptations that they had, whether they were using stone tools or not — all parts of their adaptation and behavior that we are trying to figure out,” Alemseged said. “Discoveries like this really trigger interesting questions in terms of reviewing, revising, and then coming up with new hypotheses as to what the key differences were between the main hominin groups.”

Research in the field and at the National Museum of Ethiopia is conducted with permission and under the auspices of the Ethiopian Heritage Authority of the Ministry of Tourism. Field work is undertaken with additional permission from the Afar Regional State Tourism and Culture Bureau. Funding to support field work was provided by Margaret and Will Hearst and the University of Chicago.

“First Afar Paranthropus fossil expands the distribution of a versatile genus” was published in Nature in January 2026. Co-authors are Zeresenay Alemseged, Fred Spoor, Denné Reed, W. Andrew Barr, Denis Geraads, René Bobe and Jonathan G. Wynn.