A 2,200-year-old Chinese tomb held a new gibbon species, now extinct

A royal crypt from China’s past has issued a conservation alert for apes currently eking out an existence in East Asia.

The partial remains of a gibbon were discovered in 2004 in an excavation of a 2,200- to 2,300-year-old tomb in central China’s Shaanxi Province. Now, detailed comparisons of the animal’s face and teeth with those of living gibbons show that the buried ape is from a previously unknown and now-extinct genus and species, conservation biologist Samuel Turvey and colleagues report in the June 22 Science. His team named the creature Junzi imperialis.

There’s currently no way to know precisely when J. imperialis died out. But hunting and the loss of forests due to expanding human populations likely played big roles in the demise of the ape, the researchers contend.

“Until the discovery of J. imperialis, it was thought that the worrying global decline of apes was a modern-day phenomenon,” says Turvey, of the Zoological Society of London’s Institute of Zoology. “We’re now realizing that there may have been numerous human-caused extinctions of apes and other primates in the past.”

The climate was relatively stable several thousand years ago, and no vertebrate extinctions have been definitively linked to natural climate shifts over the past 10,000 years. So “it is reasonable to conclude that Junzi became extinct as a result of human impacts,” says study coauthor Alejandra Ortiz, a paleoanthropologist at Arizona State University in Tempe.

Historical records indicate that gibbons with features similar to those of J. imperialis, as well as some other distinctive-looking gibbon populations no longer observed in the wild, inhabited central and southern China up to around 300 years ago, the researchers say. Most gibbons today are found in Southeast Asia.

The tomb is thought to have belonged to the grandmother of China’s first emperor, Qin Shihuang, who ordered the building of the Great Wall of China and the famous terra-cotta warriors (SN: 9/16/17, p. 19). Twelve pits with animal remains, including those of the gibbon, were found in the crypt. During Qin’s reign and throughout much of Chinese history, gibbons were thought to have noble traits, and royals often acquired gibbons as high-status pets. Ancient Chinese art includes many depictions of gibbons, too.

Turvey’s group compared a 3-D digital reconstruction of the gibbon’s skull, based on its skeletal remains, with 477 skulls from nearly all living species of gibbons and siamangs, a closely related ape. Digital images of the recovered gibbon’s upper and lower molar teeth were compared with 789 molars from 279 present-day gibbon and siamang individuals.

“The science in this paper is strong, but its message for the future of apes and all animals and plants on Earth today is dismal,” says biological anthropologist Brenda Benefit of New Mexico State University in Las Cruces. All species of gibbons living today remain imperiled, as do most other primates, due to serious challenges from habitat loss, hunting and the international trade in exotic pets (SN: 3/17/18, p. 10).

While the new report highlights long-standing human threats to gibbons’ survival, the ancient gibbon’s remains may not represent a new genus, holds biological anthropologist Terry Harrison of New York University. A partial skull from a captive ape of unknown geographic origin leaves crucial questions unanswered, including what the creature’s lower body looked like, Harrison says. Relatively complete skeletons of wild gibbons from Chinese sites dating to the past 10,000 years are needed to check the Shaanxi ape’s evolutionary ID, he contends.