By Midwestern U., Dec. 18, 2025
https://scitechdaily.com/this-1-5-million-year-old-human-face-is-rewriting-human-evolution/
https://scitechdaily.com/this-1-5-million-year-old-human-face-is-rewriting-human-evolution/
Map showing potential migration routes of the human ancestor, Homo erectus, in Africa, Europe and Asia during the early Pleistocene. Key fossils of Homo erectus and the earlier Homo habilis species are shown, including the new face reconstruction of the DAN5 fossil from Gona, Ethiopia dated to 1.5 million years ago.
Credit: Dr. Karen L. Baab. Scans provided by National Museum of Ethiopia, National Museums of Kenya and Georgian National Museum.
A newly reconstructed fossil face from Ethiopia reveals surprising complexity in early human evolution.
By digitally fitting together teeth and fossilized bone fragments, researchers reconstructed a strikingly well preserved face of a human ancestor that lived 1.5 million years ago. The find represents the first complete Early Pleistocene hominin cranium from the Horn of Africa and, discovered at Gona in Ethiopia, suggests that some of the earliest humans to leave Africa retained unexpectedly archaic facial features.
A fossil discovered at Gona in Ethiopia and dated to about 1.5 million years ago is offering new insight into the earliest human relatives to leave Africa.
An international research team led by Dr. Karen Baab, a paleoanthropologist at the College of Graduate Studies, Glendale Campus of Midwestern University in Arizona, created a digital reconstruction of the face of early Homo erectus. The fossil, known as DAN5 and dated to between 1.6 and 1.5 million years old, was recovered from the Afar region of Ethiopia. Its unexpectedly archaic facial structure is providing new perspectives on the species that later spread throughout Africa and into Eurasia. The research is being published in Nature Communications.
According to Dr. Baab, “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. One explanation is that the Gona population retained the anatomy of the population that originally migrated out of Africa approximately 300,000 years earlier.”
Gona, Ethiopia
The Gona Paleoanthropological Research Project, based in the Afar region of Ethiopia, is co directed by Dr. Sileshi Semaw (Centro Nacional de Investigación sobre la Evolución Humana, Spain) and Dr. Michael Rogers (Southern Connecticut State University). Research at Gona has uncovered hominin fossils dating back more than 6.3 million years, along with stone tools that document the past 2.6 million years of human technological evolution.
The Gona Paleoanthropological Research Project, based in the Afar region of Ethiopia, is co directed by Dr. Sileshi Semaw (Centro Nacional de Investigación sobre la Evolución Humana, Spain) and Dr. Michael Rogers (Southern Connecticut State University). Research at Gona has uncovered hominin fossils dating back more than 6.3 million years, along with stone tools that document the past 2.6 million years of human technological evolution.
Fossil fragments of a face as well as teeth were reassembled to produce the most complete cranium of a human ancestor from this time in the Horn of Africa.
Credit: Dr. Karen L. Baab. Scans provided by National Museum of Ethiopia. Photographs courtesy of M. Rogers and G. Suwa.
The updated reconstruction brings together a fossilized brain case (previously described in 2020) and several smaller pieces of the face from a single individual known as DAN5, which lived between 1.6 and 1.5 million years ago. Using digital methods, researchers reassembled the facial fragments (and teeth) to produce the most complete fossil human skull yet recovered from the Horn of Africa for this period.
The DAN5 specimen has been identified as Homo erectus, a species that persisted for a long time and spread widely across Africa, Asia, and Europe about 1.8 million years ago.
How did the scientists reconstruct the DAN5 fossil?
The researchers used high-resolution micro-CT scans of the four major fragments of the 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 reconstruction took about a year and went through several iterations before arriving at the final version.
The researchers used high-resolution micro-CT scans of the four major fragments of the 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 reconstruction took about a year and went through several iterations before arriving at the final version.
Photo montage of five major elements of DAN5 fossil cranium.
Credit: Dr. Michael Rogers
Dr. Baab, who was responsible for the reconstruction, described this as “a very complicated 3D puzzle, and one where you do not know the exact outcome in advance. Fortunately, we do know how faces fit together in general, so we were not starting from scratch.”
Dr. Baab, who was responsible for the reconstruction, described this as “a very complicated 3D puzzle, and one where you do not know the exact outcome in advance. Fortunately, we do know how faces fit together in general, so we were not starting from scratch.”
What did scientists conclude?
This new study shows that the Gona population 1.5 million years ago 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. Scientists 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. “I’ll never forget the shock I felt when Dr. Baab first showed me the reconstructed face and jaw,” says Dr. Yousuke Kaifu of the University of Tokyo, a co-author of the study.
“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,” says Dr. Baab. “But the DAN5 fossil postdates the initial exit from Africa, so other interpretations are possible.”
Dr. Rogers agrees. “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.”
“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,” adds Dr. Semaw.
This new study shows that the Gona population 1.5 million years ago 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. Scientists 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. “I’ll never forget the shock I felt when Dr. Baab first showed me the reconstructed face and jaw,” says Dr. Yousuke Kaifu of the University of Tokyo, a co-author of the study.
“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,” says Dr. Baab. “But the DAN5 fossil postdates the initial exit from Africa, so other interpretations are possible.”
Dr. Rogers agrees. “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.”
“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,” adds Dr. Semaw.
Future Research
The researchers are hoping to compare this fossil to the earliest human fossils from Europe, including fossils assigned to Homo erectus but also a distinct species, Homo antecessor, both dated to approximately one million years ago. “Comparing DAN5 to these fossils will not only deepen our understanding of facial variability within Homo erectus but also shed light on how the species adapted and evolved,” explains Dr. Sarah Freidline of the University of Central Florida, study co-author.
There is also potential to test alternative evolutionary scenarios, such as genetic admixture between two species, as seen in later human evolution among Neanderthals, modern humans, and “Denisovans.” For example, maybe DAN5 represents the result of admixture between classic African Homo erectus and the earlier Homo habilis species. According to Dr. Rogers, “We’re going to need several more fossils dated between one and two million years ago to sort this out.”
The researchers are hoping to compare this fossil to the earliest human fossils from Europe, including fossils assigned to Homo erectus but also a distinct species, Homo antecessor, both dated to approximately one million years ago. “Comparing DAN5 to these fossils will not only deepen our understanding of facial variability within Homo erectus but also shed light on how the species adapted and evolved,” explains Dr. Sarah Freidline of the University of Central Florida, study co-author.
There is also potential to test alternative evolutionary scenarios, such as genetic admixture between two species, as seen in later human evolution among Neanderthals, modern humans, and “Denisovans.” For example, maybe DAN5 represents the result of admixture between classic African Homo erectus and the earlier Homo habilis species. According to Dr. Rogers, “We’re going to need several more fossils dated between one and two million years ago to sort this out.”
The birth of modern Man
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