Homo naledi had a small brain but in many ways similar to that of Homo sapiens

Homo Naledi partial sSkulll (Image courtesy John Hawks. All rights reserved)
Homo Naledi partial sSkulll (Image courtesy John Hawks. All rights reserved)

An article published in the journal “Proceedings of the National Academy of Sciences” describes a research on the possible characteristics of the brain of the hominins called Homo naledi discovered in 2013 in South Africa. A team of researchers laser scanned seven fragments of the skulls discovered to create a 3D model that could reproduce their brains’ imprints. The result is that those brains were indeed small but many aspects of their structure were substantially the same as those of Homo sapiens.

The discovery of a new species of hominins in the Rising Star cave system raised considerable interest even outside the fields directly involved in the research. Called Homo naledi, this species immediately showed a curious mix of characteristics partly similar to those of Homo sapiens but in part much more primitive.

This discovery generated a lot of discussions, also because initially there was no way to perform a dating and the discoverers wanted to wait as much as possible before taking the bone samples needed for a direct dating. About a year ago, a research described the results of indirect dating indicating that the fossils of Homo naledi were between 236,000 and 335,000 years old.

In essence, the fossils of Homo naledi are more recent than expected, which means that they lived at the same time as archaic Homo sapiens. This made it more important than ever to try to understand Homo naledi’s mental abilities to hope to determine who actually produced the stone tools of that time discovered in the areas where both species lived.

The imprints of the brain left on the bones of the skull under certain conditions gave a helping hand to recreate in at least approximately Homo naledi’s brain structure. A laser scan made it possible to create a 3D model of these hominins’ brain in a new study that included some researchers involved since the discovery of the first fossils.

The result of the study is that the back of the brain is different than, for example, australopithecus, the left hemisphere is a little displaced forward compared to the right one, the visual area is relatively smaller than that of chimpanzees and the left hemisphere doesn’t have the frontal lobe characteristics typical of australopithecus and apes but has a frontal operculum.

In short, Homo naledi had a brain that was in many ways a smaller version of modern humans’. John Hawks, one of the authors of the research, stated that it’s the kind of brain that is expected for Homo habilis, who however lived two million years ago. His fellow researcher Lee Berger pointed out that this study could lead archaeologists to reconsider the origin of stone tools of that era.

One of the questions about Homo naledi concerns his language skills. Shawn Hurst, another of the authors of this study, stated that it’s still too early for speculations, but the anatomy of the frontal lobe of these hominins’ brain is similar to that of modern humans and language is a skill linked to that cerebral region.

These results are very interesting and at the same time still leave various questions regarding Homo naledi unanswered. Modern technologies are helping a lot paleontologists and paleoanthropologists in the study of extinct species but giving final answers can still be difficult if not impossible. The ongoing progress in these fields offers hopes for new discoveries.

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