Human history may have a new wrinkle.
In a research paper published this week in Science, paleo-anthropologist Xiu-Jie Wu announced the discovery of two nearly intact skull caps. The skulls date back more than 100,000 years ago, and researchers say they could belong to either a new kind of human or an Asian variant of Neanderthals.
The skull caps’ characteristics have led researchers to believe that owners had a mix of modern human and Neanderthal DNA, which may reveal a new thread of human development.
Speaking to Ars Technica, Wu said the skull cap owners belong to a group of “new or unknown archaic humans” that paleo-archaeologists have not seen before, and that this “mosaic” of modern and Neanderthal genetic traits are “not known among early Late Pleistocene humans in the western Old World.”
The paper concludes by saying that the unknown people possibly came from Neanderthals mixing with other ancient populations over the course of millennia.
Scientifically called a crania, researchers have given the two skull caps the nickname of Xuchang 1 and 2. Wu and her team found them in Henan, China, in an area that housed a spring during the Pleistocene period.
In the area the researchers also found remains of extinct megafauna, the giant ancestors of animals such as cows, deer, rhinos, elk, and horses. The animal bones in the graves of Xuchang 1 and 2, plus the array of quartz-based stone tools, have led the researchers to believe that the unknown humans were successful hunters.
University College London anthropologist María Martinón-Torres told Science News that Xuchang 1 and 2 might be the first Denisovans — another subspecies of early human — discovered with intact crania. Researchers have only recovered a few Denisovan fingers and teeth before, but the DNA sequenced from those finds has led scientists such as Martinón-Torres to describe Denisovans as humans “with an Asian flavor but closely related to Neanderthals.”
Wu’s team did not want to describe Xuchang 1 and 2 as Denisovans, however. The term is a “DNA sequence” and nothing more, anthropologist Erik Trinkaus, a co-author on the new study and the person who popularized the theory that humans and Neanderthals procreated together, told Science News.