A gravely crushed skull upset decades of a river in the center of China that has challenged the classification that now shakes the human family tree, according to a new analysis.
Scientists have digitally rebuilt the crushed skull, considered a million years, and its characteristics suggest that the fossil belonged to the same line as a striking specimen called “Dragon Man” and Denisovans – an enigmatic and recently discovered population of prehistoric humans with troubled origins. The age and categorization of the skull as an ancient ancestor of Denisovan would mean that the group is much earlier than thought.
The broader analysis of researchers, based on reconstruction and more than 100 other skull fossils, also sketched an image radically different from human evolution, they reported Thursday in the journal Science. The results considerably move the chronology of species such as ours, Homo sapiens and homo neanderthalensis. Neanderthals, archaic humans who lived in Europe and Central Asia before disappearing around 40,000 years ago, are known for having lived alongside Denisovans and agreed with them.
“This changes a lot of reflection because he suggests that a million years ago, our ancestors had already divided into distinct groups, pointing towards a much more previous human scission and more complex than we thought before,” said the co-author of the Chris Stringer study, paleoanthropologist and research chief in human evolution in Natural Museum in London, in an e-mail.
The results, if they were widely accepted, would reject the emergence of our own 400,000 years species and considerably reshape what we know about human origins.
The skull is one of the two partially mineralized specimens unearthed in 1989 and 1990 in an area known as Yunxian in Shiyan, located in the province of Hubei, in the center of China. A third skull discovered nearby in 2022 has not yet been officially described in the scientific literature, noted Stranger.
“We have decided to study this fossil again because it has reliable geological meetings and is one of the rare human fossils of one million people,” said the first author of the Xiaobo Feng study, professor at Shanxi University in China, in a press release. “A fossil of this age is essential to rebuild our family tree.”
The two Yunxian skulls were distorted from millennia passed underground, but the second, known as Yunxian 2, was better preserved. This specimen constituted the basis of the new reconstruction, which used the cutting -edge computed tomography, light imaging and virtual techniques to separate the bones from the rock matrix which locked them, and to correct the distortions inherent in the fossil.
The age of the skull, determined by dating from the layer of sediment in which it was found and fossils of mammals found in the same layer, had led some experts to believe that it belonged to Homo Erectus, a more primitive human species known to have lived in many places in the world at that time. However, while Yunxian 2 Squat’s big breeding breaks looked like that of Homo Erectus, other characteristics of the skull, such as flat and shallow cheekbones, did not do so.
Stringer and his colleagues concluded that Yunxian 2 belonged to an ancient ancestor of the Dragon Man, officially called Homo Longgi. Scientists identified Dragon Man in 2021 from a skull found at the bottom of a well in northeast China, and the authors of a June study used old DNA to connect Homo Longi to Denisovans, a dark population known from genetic information extracted from some fossil fragments but thought they had lived in a large part of Asia.
The latest analysis also suggests that other difficult to classify fossils discovered in China should be grouped with Homo Longi and Denisovans – including fossils that another research team has recently proposed as a new species that they called Homo Juluensis, a name that roughly translates into a man with high drop.
Strunger said that the third fossil of the Yunxian skull, once the researchers are preparing and studying it in detail, will allow the team to test the accuracy of reconstruction and its placement in the human family tree.
With revealing bumps and ridges, the skulls are particularly informative in the study of human evolution because they have many characteristics, and a skull is generally the sample which can definitively confirm a newly discovered species.
The use of information from the new digital reconstruction and anatomical information of 104 skulls and jaws in the human fossils file, Stringer and its co -author Xijun Ni, professor at the Institute of Paleontology of Vertebrates and Paleoanthropology in Beijing, rebuilt the evolutionary relationships between the different groups using a mathematical program used in evolutionary biology. The team has reconstructed what is called a phylogenetic tree showing how different human species can have diverged from each other in the past 1 million years.
The analysis suggests that the origins of Homo sapiens, Denisovans and Neanderthals are much older than we thought before.
The discovery questions the traditional vision, based on studies of ancient DNA, that the three species began to diverge from an ancestor common to around 700,000 to 500,000 years – although it was never clear which this ancestral species, sometimes nicknamed Ancetor X, was.
Denisovans and modern humans shared a common ancestor about 1.32 million years ago, according to the new analysis. Neanderthals have moved away from this scalable line earlier, about 1.38 million years ago, the study suggested. The results mean That the Denisovans are more closely linked to us than the Neanderthals, who had been considered by many as sisters closest to Homo Sapiens, the researchers wrote.
The reconstruction of the deformed skull looked good, said Ryan Mcrae, paleoanthropologist at the Smithsonian National Museum of Natural History in Washington, DC. McRae, who was not involved in research, agreed that she was in a longi longi form and the Denisovans.
However, McRae is less convinced by the analysis of phylogenetic trees and said that the team may have tried to “do too much with limited data”.
“This study indicates that Denisovans (Homo Longi) and Homo Sapiens are more closely linked to the exclusion of Neanderthals,” he said. “It also goes further by saying that the origins of all these groups are much older than expected, about twice older if not more. This would firmly place the origins of all these groups at the time of Homo Erectus.
“At this point, I think that the safest thing to say is that the Homo Longi / Denisovan group and Homo Sapiens (including very archaic fossils and modern humans) are more like what they do to Neanderthals,” he added by email.
If the time reported in this article is precise, McRae said that the only candidate for the common ancestor of Homo Sapiens, Homo Longi and Homo Neanderthalensis would be homo erectus. “There is really not another known species from the period of ~ 1.5 million years that would make sense,” said McRae.
Homo anti -cess human species are known to have lived around 1 million years ago, and another, Homo Heidelbergensis about 700,000 years ago, he added.
Strunger said that he provided that the results would attract a certain skepticism and that researchers plan to extend their analyzes to include other data and other fossil sources, including more Africa, to refine the table.
The study raises a broader question about the place where the ancestral populations of Homo Sapiens, Neanderthals and Homo Longi lived: inside or outside Africa, which is largely considered to be the cradle of humanity, noted Stringer.
The authors said that if the study is progressing towards the resolution of what paleoanthropologists call “confusion in the middle” – the confusing range of human specimens in the fossil file between 1 million and 300,000 years – finds like the Yunxian 2 skull also underlines how much scientists have to learn about human origins.
“When I started working in human evolution over fifty years ago, the Eastern Asian record was either marginalized, or its fossils have only been considered direct ancestors of recent Asians in the East,” said Stringer by email. “But what we now see from Yunxian – and … many other sites – is that East Asia preserves crucial clues on the subsequent stages of human evolution.”
