A major discovery in central China could totally change how we think about ancient humans, and it was all based on an anlysis of skulls found back in 2007 and 2014. Researchers announced in a paper published in the journal Science that they believe two skulls found in Lingjing, China are between 100,000 and 130,000 years old, and they have a fascinating story behind them.

The skulls are interesting because they appear to have the ear canals of Neanderthals, but have brainpans that are low and flat like eastern Eurasians, with some resemblance to Old World humans. That means these skulls seem to belong to a completely new species that is neither Neanderthal nor human. They could be Denisovans, an ancient cousin to humans that may have interbred with both Neanderthals and humans.

It’s a major finding because it could shed a lot of light on the strange dynamics of human and Neanderthal relations, which scientists have been trying to understand due to the fact that we still have a lot of Neanderthal in us today from interbreeding.

The full statement from the Washington University in St. Louis is below.

Two partial archaic human skulls, from the Lingjing site, Xuchang, central China, provide a new window into the biology and populations patterns of the immediate predecessors of modern humans in eastern Eurasia.

Securely dated to about 100,000 years ago, the Xuchang fossils present a mosaic of features.

With late archaic (and early modern) humans across the Old World, they share a large brain size and lightly built cranial vaults with modest brow ridges.
With earlier (Middle Pleistocene) eastern Eurasian humans, they share a low and broad braincase, one that rounds onto the inferior skull.
With western Eurasian Neandertals, they share two distinct features — the configuration of their semicircular canals and the detailed arrangement of the rear of the skull.
“The biological nature of the immediate predecessors of modern humans in eastern Eurasia has been poorly known from the human fossil record,” said Erik Trinkaus, a corresponding author for the study and professor of anthropology at Washington University in St. Louis. “The discovery of these skulls of late archaic humans, from Xuchang, substantially increases our knowledge of these people.”

More importantly, he noted: “The features of these fossils reinforce a pattern of regional population continuity in eastern Eurasia, combined with shared long-terms trends in human biology and populational connections across Eurasia. They reinforce the unity and dynamic nature of human evolution leading up to modern human emergence.”

The study is co-authored by researchers from institutions in Beijing, Zhengzhou and Shanghai, China, including Zhan-Yang Li, Xiu-Jie Wu, Wu Liu, Xing Gao, Xiao-Mei Nian and Li-Ping Zhou. This work has been supported by the National Natural Science Foundation of China and the Chinese Academy of Science.

Li, Z.Y., Wu, X.J., Zhou, L.P., Liu, W., Gao, X., Nian, M.N., Trinkaus, E. (2017) Late Pleistocene archaic human crania from Xuchang, China. Science (in press).

The abstract of the paper is below.

Excavations in eastern Asia are yielding information on human evolution and migration. Li et al. analyzed two fossil human skulls from central China, dated to 100,000 to 130,000 years ago. The crania elucidate the pattern of human morphological evolution in eastern Eurasia.

Some features are ancestral and similar to those of earlier eastern Eurasian humans, some are derived and shared with contemporaneous or later humans elsewhere, and some are closer to those of Neandertals. The analysis illuminates shared long-term trends in human adaptive biology and suggests the existence of interconnections between populations across Eurasia during the later Pleistocene.

Two early Late Pleistocene (~105,000- to 125,000-year-old) crania from Lingjing, Xuchang, China, exhibit a morphological mosaic with differences from and similarities to their western contemporaries. They share pan–Old World trends in encephalization and in supraorbital, neurocranial vault, and nuchal gracilization. They reflect eastern Eurasian ancestry in having low, sagittally flat, and inferiorly broad neurocrania.

They share occipital (suprainiac and nuchal torus) and temporal labyrinthine (semicircular canal) morphology with the Neandertals. This morphological combination reflects Pleistocene human evolutionary patterns in general biology, as well as both regional continuity and interregional population dynamics.

Here is a statement from Cell Press on another recent study that came to a fascinating conclusion about Neanderthals and humans.

The last Neanderthal died 40,000 years ago, but much of their genome lives on, in bits and pieces, through modern humans. The impact of Neanderthals’ genetic contribution has been uncertain: Do these snippets affect our genome’s function, or are they just silent passengers along for the ride? In Cell on February 23, researchers report evidence that Neanderthal DNA sequences still influence how genes are turned on or off in modern humans. Neanderthal genes’ effects on gene expression likely contribute to traits such as height and susceptibility to schizophrenia or lupus, the researchers found.

“Even 50,000 years after the last human-Neanderthal mating, we can still see measurable impacts on gene expression,” says geneticist and study co-author Joshua Akey of the University of Washington School of Medicine. “And those variations in gene expression contribute to human phenotypic variation and disease susceptibility.”

Previous studies have found correlations between Neanderthal genes and traits such as fat metabolism, depression, and lupus risk. However, figuring out the mechanism behind the correlations has proved difficult. DNA can be extracted from fossils and sequenced, but RNA cannot. Without this source of information, scientists can’t be sure exactly if Neanderthal genes functioned differently than their modern human counterparts. They can, however, look to gene expression in modern humans who possess Neanderthal ancestry.