Two skulls from Yunxian, in northern China, aren’t ancestors of Denisovans after all; they’re actually the oldest known Homo erectus fossils in eastern Asia.
A recent study has re-dated the skulls to about 1.77 million years old, which makes them the oldest hominin remains found so far in East Asia. Their age means that Homo erectus (an extinct common ancestor of our species, Neanderthals, and Denisovans) must have spread across the continent much earlier and much faster than we’d previously given them credit for. It also sheds new light on who was making stone tools at some even older archaeological sites in China.
Homo erectus spread like wildfire
Yunxian is an important—and occasionally contentious—archaeological site on the banks of central China’s Han River. Along with hundreds of stone tools and animal bones, the layers of river sediment have yielded three nearly complete hominin skulls (only two of which have been described in a publication so far). Shantou University paleoanthropologist Hua Tu and his colleagues measured the ratio of two isotopes, aluminum-26 and beryllium-10, in grains of quartz from the sediment layer that once held the skulls. The results suggest that Homo erectus lived and died along the Han River 1.77 million years ago. That’s just 130,000 years after the species first appeared in Africa.
(Side note: This river has been depositing layers of silt and gravel on the same terraces for at least 2 million years, and that’s just extremely cool.)
The revised date suggests that Homo erectus spread across Asia much more quickly than anthropologists had realized. So far, the oldest hominin bones found anywhere outside Africa are five skulls, along with hundreds of other bones, from Dmanisi Cave in Georgia. The Dmanisi bones are between 1.85 million and 1.77 million years old, and they (probably—more on that below) also belong to Homo erectus.
Until recently, the next-oldest Homo erectus fossils outside Africa were the 1.63-million-year-old fossils from another Chinese site, Gongwangling, a short distance north of Yunxian. (That’s not counting a couple of teeth from a site in southern China with an age that is a little less certain.) Those dates had suggested Homo erectus seemed to have taken a leisurely 140,000 years to spread east into Asia. But it now looks like hominins were living in Georgia and central China at about the same time, which means they spread out very fast, started earlier than we knew, or both.