A digital reconstruction of the Yunxian 2 skull, a million-year-old fossil found in China's Hubei Province, is prompting a significant re-evaluation of human evolutionary history. Published on September 25, 2025, the study suggests this ancient cranium belongs to an early member of the Homo longi lineage, a group closely related to modern humans and Denisovans. This finding pushes back the estimated divergence time between Homo sapiens and Homo longi considerably, challenging long-held timelines. The Yunxian 2 skull, discovered in 1990, had long puzzled researchers due to severe deformation during fossilization, hindering previous classification attempts.
Utilizing advanced CT scanning and digital reconstruction techniques, scientists were able to virtually restore the skull, revealing a braincase volume of approximately 1,143 cubic centimeters. The reconstructed skull exhibits a mosaic of primitive traits, such as a pronounced brow ridge and a forward-jutting face, alongside more modern characteristics like a higher cheek region and a reduced occipital ridge. Phylogenetic analyses based on this reconstruction indicate that the common ancestor of Homo sapiens and Homo longi existed around 1.32 million years ago, a substantial revision from previous estimates of 500,000 to 700,000 years ago. This suggests that Denisovans, Neanderthals, and modern humans followed separate evolutionary paths for a much longer period than previously understood, pointing to a more complex and earlier branching of human lineages.
The implications of this discovery extend to our understanding of the Homo longi clade, now considered a sister group to Homo sapiens, which likely included the Denisovans. The Yunxian 2 skull, along with the 'Dragon Man' skull (Harbin cranium) found in China and dated to at least 146,000 years ago, are key pieces in understanding this lineage. This research underscores the power of advanced digital reconstruction technologies in overcoming the limitations of fossilized remains, revolutionizing the field by allowing for more accurate visualization and analysis of ancient specimens. The findings from the Yunxian 2 skull reshape our perception of human evolutionary timelines and emphasize the dynamic nature of scientific discovery in understanding our origins. The study was published in the journal *Science*.