We’re used to ancient tombs containing the material riches of gold and jewels, but a 2,300-year-old tomb discovered in China has been found to harbor a different kind of treasure. Amongst the more conventional artifacts, researchers found the skull of what is now believed to be a new and extinct genus of gibbon.

The bones were excavated from one of 12 burial pits within an ancient tomb uncovered back in 2004 in Shaanxi Province, China. These pits contained the remains of other animals – including leopards, lynx, Asiatic black bears, cranes, and domestic livestock – as was common in high-status burials of the time. But what interested researchers from the Zoological Society of London was the skull of a gibbon. Their study is published in the journal Science.

In ancient China, gibbons were seen as noble creatures, and so considered culturally significant. Symbols of scholars-officials (politicians appointed by the Chinese emperor, and known as junzi), the small apes became high-status pets in the Zhou Dynasty.

Yet due to the wet, humid climate in which they tend to live, ancient gibbon bones are not particularly common, making the remains found in the high-status tomb of real significance. But while studying the bones from the burial pit, the scientists came to a startling conclusion. Not only did they not belong to any species of gibbon alive today, they should be classed in their own genus.

Calling the new genus and species Junzi imperialis, the team went back through historical records to see if they could piece together the history of this forgotten about ape. They think that the gibbon was likely still clinging on to survival until just 300 years ago, and it may be the only known primate to have gone extinct due to human hunting and habitat loss (though for how much longer, we'll see).

“Our discovery and description of Junzi imperialis suggests that we are underestimating the impact of humans on primate diversity,” explained ZSL’s Dr Samuel Turvey. “These findings reveal the importance of using historical archives such as the archaeological record to inform our understanding of conservation and stress the need for greater international collaboration to protect surviving populations of gibbons in the wild.”

The tomb is thought to be the last resting place of Lady Xia. While her husband at the time, Lord Anguo, only reigned briefly as King Xiaowen of Qin for three days in 250 BCE, her decedents were a little more successful, as she is the grandmother of Qin Shi Huang. As the first Chinese emperor, Qin Shi Huang cemented his place in history by constructing the Terracotta Army to protect him in the afterlife.

While the impressive statutes have been able to give us a wealth of information about ancient Chinese culture, Lady Xia’s tomb has given us a window into the ancient Chinese environment.