Paleoanthropologists have examined and reconstructed DAN5, a 1.5-million-year-old fossilized skull of early Homo erectus found in Gona in the Afar region of Ethiopia.
This is an artist’s reconstruction of Homo erectus. Image credit: Yale University.
“We already knew that the DAN5 fossil had a small brain, but this new reconstruction shows that the face is also more primitive than classic African Homo erectus of the same antiquity,” said Dr. Karen Baab, a paleoanthropologist at Midwestern University.
“One explanation is that the Gona population retained the anatomy of the population that originally migrated out of Africa approximately 300,000 years earlier.”
For the study, Dr. Baab and colleagues used high-resolution micro-CT scans of the four major fragments of the DAN5’s face, which were recovered during the 2000 fieldwork at Gona.
3D models of the fragments were generated from the CT scans. The face fragments were then re-pieced together on a computer screen, and the teeth were fit into the upper jaw where possible.
The final step was ‘attaching’ the face to the braincase to produce a mostly complete cranium.
“This is a very complicated 3D puzzle, and one where you do not know the exact outcome in advance,” Dr. Baab said.
“Fortunately, we do know how faces fit together in general, so we were not starting from scratch.”
The study shows that the Gona hominin population had a mix of typical Homo erectus characters concentrated in its braincase, but more ancestral features of the face and teeth normally only seen in earlier species.
For example, the bridge of the nose is quite flat, and the molars are large.
The researchers determined this by comparing the size and shape of the DAN5 face and teeth with other fossils of the same geological age, as well as older and younger ones.
A similar combination of traits was documented previously in Eurasia, but this is the first fossil to show this combination of traits inside Africa, challenging the idea that Homo erectus evolved outside of the continent.
“The oldest fossils belonging to Homo erectus are from Africa, and the new fossil reconstruction shows that transitional fossils also existed there, so it makes sense that this species emerged on the African continent,” Dr. Baab said.
“But the DAN5 fossil postdates the initial exit from Africa, so other interpretations are possible.”
“This newly reconstructed cranium further emphasizes the anatomical diversity seen in early members of our genus, which is only likely to increase with future discoveries,” said Dr. Michael Rogers, a paleoanthropologist at Southern Connecticut State University.
“It is remarkable that the DAN5 Homo erectus was making both simple Oldowan stone tools and early Acheulian handaxes, among the earliest evidence for the two stone tool traditions to be found directly associated with a hominin fossil,” added Dr. Sileshi Semaw, a paleoanthropologist at the Centro Nacional de Investigación sobre la Evolución Humana.
The findings appear today in the journal Nature Communications.
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K.L. Baab et al. 2025. New reconstruction of DAN5 cranium (Gona, Ethiopia) supports complex emergence of Homo erectus. Nat Commun 16, 10878; doi: 10.1038/s41467-025-66381-9
