An article published in the journal “Science” reports the results of a study of the fossil skull cataloged as Yunxian 2, which attributes it to the species Homo longi. A team of researchers examined a reproduction of this skull made after performing a CT scan, an operation that was needed to try to restore it to its original shape because the fossil is crushed.

The image (Courtesy Feng, X., Yin, Q., Gao, F., Lu, D., Fang, Q., Feng, Y., Huang, X., Tan, C., Zhou, H., Li, Q., Zhang, C., Stringer, C., & Ni, X. (2025). The phylogenetic position of the Yunxian cranium elucidates the origin of Homo longi and the Denisovans. Science. https://doi.org/ado9202 All rights reserved) shows views of the reproduction of the original shape of the Yunxian 2 skull.

The result was compared with 100 other hominin specimens, revealing a combination of traits, some close to those of Homo erectus and others much more similar to those of Homo sapiens and the species called Homo longi. In the end, the researchers concluded that this skull belongs to an early Homo longi.

The species Homo longi includes the Denisovans, another human group that is still poorly known. This study accepts the dating of this skull that places it at approximately one million years ago, indicating that this species diverged from the ancestors of Homo sapiens earlier than previously thought.

The Yunxian 2 skull was discovered in 1990 in China’s Yunyang district, the second of three skulls discovered over the years in that area. These skulls are nearly complete, but the first two in particular exhibit crushing and distortions that have made their study very complex. As a result, over the years, various studies of the first two Yunxian skulls have attributed them to different hominin species.

In recent years, the use of modern technologies in paleontology to create three-dimensional reconstructions of fossils has become widespread. The Yunxian 2 skull was subjected to a CT scan that allowed this type of reconstruction to be obtained, which, in this case, was used to try to reproduce its original shape as faithfully as possible.

According to the researchers, the Yunxian 2 skull exhibits some primitive features of Homo erectus but has a brain capacity close to that of Homo longi and Homo sapiens. In the end, they attributed it to a primitive Homo longi exhibiting some transitional features.

The dating of the Yunxian 2 skull is also important because it could change the history of human evolution. Animal fossils discovered in the same area led to dating this skull to between 400,000 and 600,000 years, but another dating based on geological analysis has led to think that it’s much older, between 940,000 and 1,100,000 years old. This latter dating is the one accepted by the authors of this new study of the skull. It would indicate that the divergence between the species Homo longi and the ancestors of Homo sapiens occurred earlier than previously thought.

These uncertainties make it difficult to assess how this attribution of the Yunxian 2 skull might influence the reconstruction of human history. The species Homo longi was proposed in 2021, but it’s not the only proposal that includes various hominin fossils discovered in recent decades. In 2024, the species called Homo juluensis was proposed, which includes other fossils discovered in Asia. These fossils include those attributed to the Denisovans, a group of ancient humans known from only a few bones, but for whom we have several DNA samples thanks to the very well-preserved bones found in Siberia.

Controversy and discussions surrounding the attribution of fossils are inevitable, given that they’re often incomplete, and even within the same species, it’s normal to have some variability in anatomical characteristics. Human history is also marked by interbreeding between different populations that are now considered to be part of different species, further complicating studies.

Studies conducted in recent years are providing answers but also new questions regarding the reconstruction of the family tree of the whole Homo genus. The possible presence of primitive Homo longi in present-day China, and therefore outside of Africa, adds new grounds for discussion regarding the diversification of various species. There will undoubtedly be further developments in the study of the complex history of humanity.