The digital reconstruction of the Yunxian 2 skull found in China could chart a new path in the theory of human evolution by revealing that it belonged to an early branch of the Asian Homo longi, a “sister” lineage of modern humans, according to a study published by Science.
The process with advanced technology to which the fossil, which dates back around a million years ago, was subjected by researchers from the Chinese University of Fudan and the Natural History Museum of the United Kingdom made it possible to correct previous distortions, thus clearing up the mystery of its place in the evolutionary line.
Based on their research, the authors of the study maintain that the separation between Homo sapiens and the lineages of the Neanderthals and the little-known Denisovans could have occurred at least half a million years earlier than previously thought, the aforementioned Museum highlights in a statement.
The fossil evidence available so far indicates that multiple lineages of Homo with different physical characteristics coexisted during the Middle Pleistocene, but the poor condition of the skulls and other remains recovered from this era meant that the interpretation of the species was surrounded by uncertainties.
Thus, the three Yunxian skulls – recovered in 1990 in the central Chinese province of Hubei – showed primitive features of Homo erectus but also others that suggested their belonging to later species such as sapiens, but Yunxian 2 was so deteriorated that it was impossible to place it in the evolutionary line.
The new analysis suggests that all large-brained humans from the last 800,000 years can “probably” fall into one of these five groups: Asian Homo erectus, Homo heidelbergensis, Homo neanderthalensis, Homo sapiens and Homo longi, to which the Denisovans are believed to belong.
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The Yunxian skulls were considered probably corresponding to Homo erectus
“What is revolutionary about our analysis is that it suggests that the origins of these five lineages go back more than a million years, which is much longer than previously thought,” says Professor Chris Stringer, one of the authors of the study.
Before the reconstruction, the Yunxian skulls were considered probably corresponding to Homo erectus, but after the process, the result moved away from this lineage to more closely resemble a fossil known as Dragon Man, another skull discovered in 2021 in China and inscribed in the species Homo longi.
Existing specimens of this species have among their distinctive features a larger skull, a smaller separation between the eyes, a deeper glabellar depression and a lower and elongated frontal bone, all characteristics now clearly visible in Yungxian 2.
“Our analysis suggests that the Yunxian skulls are an early member of the same group as Dragon Man. And because Dragon Man increasingly appears to be a Denisovan, there is a lot of evidence pointing to the fact that the Yunxian fossils also belong to that group,” Stringer says.
In this way, the age of the Yunxian skulls would indicate that the Denisovan lineage would have separated from other human lineages at least a million years ago, which places them as the closest extinct species to Homo sapiens and would imply that it is just as old.
Until now, Homo sapiens and Neanderthalensis were considered to have last shared a common ancestor half a million years ago.
The thesis defended by the researchers is that there are early members of the lineages of Homos heidelbergensis, neanderthalensis and sapiens who have not yet been found or, if they have been found, they have not been properly identified.
With information from EFE.
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