Skull found in China points to an unknown human species

Archaeologists discovered lower jaw fragments dating back to 300,000 years ago in China that may have belonged to a previously unknown human ancestor, possibly indicating a new long-lost distant relative of mankind, a new study said.

The lower jaw fragments that were discovered reportedly belonged to a child between the ages of 12 and 13 and may date back to the late Middle Pleistocene period.

The findings of this study were published in the peer-reviewed academic periodical the Journal of Human Evolution.

Oh the humanity('s ancestors): Finding the long-lost relatives of Homo sapiens

Humans first showed up hundreds of thousands of years ago, with the earliest known remains being in Africa, before eventually spreading all over the world. However, this follows hundreds of thousands of years of evolution, with there having been dozens of other hominid species since Homo erectus first stood upright around two million years ago.

In China, a number of hominids have been found that date back to the late Middle Pleistocene period. However, the findings covered in this study stand out among them and may change our understanding of that period's evolutionary pattern.

Found in Hualongdong back in 2015, the fossil in question is a skull that has since been designated HLD 6. 

When studying it, the researchers compared it to modern humans and other hominids from that time period.

In some respects, the skull looked very similar to modern humans, particularly the facial structure. But other aspects of the skull seem to significantly diverge. Chief among these differences is the distinct lack of a chin, a trait this hominid may have shared with the Denisovans, a cousin of humanity that branched off evolutionarily from the rest hundreds of thousands of years ago. 

This would mean that human-like characteristics would have to have manifested in China long before any humans actually came to the region, still being in Africa at this time.

This sort of characteristic, having traits both similar to modern humans and to other older hominids like Denisovans, is unprecedented in late Middle Pleistocene China. 

Except it might not be.

One thing that the researchers have noted is that there have been some of these variants in hominid remains from this era in China before. However, these have been often dismissed as being likely just individual anomalies rather than signs of a greater overall trend. 

But because of these findings, there may be something more going on here.

"The data presented suggest a distinctive combination of features that supports the idea of a third human lineage in China, not sapiens nor Neanderthal," London Natural History Museum human evolution research leader Chris Stringer, who was not involved in the study, told Live Science.

This has considerable implications for our understanding of how humans have evolved over time, as it shows how gradual and varied our development may have been. 

Considering how widespread hominids are known to have been before Homo sapiens arrived, it is possible that more branches on the hominid family tree existed that scientists have yet to find. 

More research will need to be done to figure out just where on the tree HLD 6 may have been.