China’s million-year-old skull may rewrite where and when humans began

A fossilized skull discovered in central China and dated to roughly 1 million years old has upended the timeline of human evolution. In a study published in the journal Science on Thursday, researchers report that the cranium, known as Yunxian 2, shows that modern humans diverged from ancient relatives about 400,000 years earlier than previously believed, redrawing one of the most fundamental chapters of our species’ history.

The Yunxian 2 skull was unearthed in 1990 in Hubei province, but its crushed and distorted condition left researchers uncertain about its identity for decades. Initially assigned to Homo erectus, the fossil offered few clear traits that could place it securely within the human evolutionary tree. Geological pressure had flattened much of the cranium, masking features vital to understanding its significance.

By applying CT scanning and advanced digital reconstruction, scientists restored the fossil’s shape and compared it with more than 100 other hominin skulls. Their analysis revealed that Yunxian 2 did not belong to Homo erectus, but instead fit within a lineage that includes Homo longi and the Denisovans. This finding positions the skull much closer to the branch where the ancestors of modern humans, Neanderthals and Denisovans began to diverge.

Dating methods indicate the fossil is between 940,000 and 1.1 million years old, predating the widely accepted 500,000 to 700,000 year estimate for the evolutionary split. The study argues that this divergence must have occurred nearly 400,000 years earlier than previously thought.

Chris Stringer of London’s Natural History Museum, a co-author of the research, said, “This changes a lot of thinking because it suggests that by 1 million years ago, our ancestors had already split into distinct groups, pointing to a much earlier and more complex human evolutionary split than previously believed.”

The findings also raise the possibility that the key divergence took place in western Asia, supported by evidence of evolutionary diversity in fossils across the region. The authors suggest that the Homo longi clade may have lived in relatively small, isolated groups, which could explain their distinctive features. While the study provides new insight into a poorly understood period of human history, researchers note that further fossils and genetic evidence will be required to test its conclusions.

Ryan McRae of the Smithsonian National Museum of Natural History, who was not involved, praised the reconstruction but cautioned that the team may have tried “to do too much at once with limited data” and said a safer reading is that the Homo longi or Denisovan group and Homo sapiens look more similar to each other than to Neanderthals.