In September 2025, a team of Chinese and international researchers published a startling reinterpretation of a fossil skull first excavated in 1990, suggesting that it may belong to a sister lineage of Homo sapiens and potentially push back the timeline of our evolutionary divergence.
This study, centered on the specimen dubbed Yunxian 2, has reignited debate over the long‑standing “Out of Africa” model of human origins. Below is an overview of the discovery, its implications, and the challenges it poses to prevailing theories.
Yunxian 2
The skull now called Yunxian 2 was recovered in the early 1990s at a site in Hubei Province, central China, but for decades its scientific significance remained muted because the fossil was heavily distorted by geological pressures.
In many early analyses it had been treated as a variant of Homo erectus, largely by default, because few alternative human lineages were widely accepted for that period.
After decades in limbo, researchers applied advanced imaging techniques, including CT scanning, structure‑light mapping, and digital virtual reconstruction, to model what the original skull shape might have been.
These reconstructions allowed a reanalysis of its morphology in comparison with dozens of other hominin fossils.
Through this process, the researchers estimated that the skull is between 940,000 and 1.1 million years old, making it one of the oldest candidate hominin fossils in East Asia that can be meaningfully compared to later human lineages.
A New Lineage
What makes this newly reconstructed skull especially provocative is its interpreted phylogenetic placement. The authors of the study argue that Yunxian 2 does not comfortably fit within conventional Homo erectus or Homo heidelbergensis morphologies.
Instead, they place it within or as a close relative to the Homo longi lineage, also associated with Denisovans and sometimes nicknamed “Dragon Man.” In their view, the Yunxian lineage represents a sister branch to modern humans, diverging early in the Homo family tree.
Under this scenario, the divergence between Homo sapiens and its sister lineages might date back to over one million years ago, rather than the more conventional estimates of 500,000 to 700,000 years ago.
The authors also propose that the Neanderthal lineage split off first (perhaps ~1.38 million years ago), followed by a longi/Denisovan branch around ~1.2 million years ago, and then the Homo sapiens branch at ~1.02 million years ago.
If the interpretation holds, it suggests that the human family tree is much deeper and more ramified in Eurasia than previously imagined, with multiple branches evolving in parallel and potentially interbreeding over long times.
Challenging the “Out of Africa” Theory
The classical “Out of Africa” model holds that anatomically modern humans evolved within Africa (roughly 300,000 to 200,000 years ago) and then dispersed outward, replacing or partially interbreeding with archaic populations in Eurasia.
Genetic data, especially from mitochondrial DNA, Y chromosomes, and modern human genomic diversity, has long been cited as strong evidence for this scenario.
The Yunxian 2 discovery does not necessarily overthrow that general framework, but it does pose a serious challenge to its timeline and to assumptions of exclusivity.
The idea that Homo sapiens (or its immediate ancestors) diverged so early from other lineages suggests that significant human evolution might have occurred outside Africa as well as within it.
Also, that East Asia may have played a more central role in shaping archaic human diversity than previously believed.
Some paleontologists propose that the “Muddle in the Middle”, the confusing fossil record between about 300,000 and 1,000,000 years ago, may reflect exactly this complexity.
It's about how multiple overlapping human lineages in Africa, Eurasia, and possibly in multiple regions, with gene flow between them.
The Yunxian skull may thus help resolve or at least sharpen debates about which fossils relate to Homo sapiens ancestry and which belong to side branches.
