Mysterious human relatives were strong and agile, fossil elbow and primitive tools suggest

Seven ancient human fossils and a cache of tools and animal remains found in a cave in southwestern China are illuminating the looks and lifeways of the mysterious Denisovans, who were close cousins of the Neanderthals and coexisted—and interbred—with modern humans, as well. One fossil, a partial elbow, is the first Denisovan arm bone identified, offering a tantalizing glimpse of their dexterity—and stone and bone cutters and scrapers found nearby reveal how they put it to use. The findings from the approximately 150,000-year-old fossils, reported in a pair of papers today in Nature, underscore how much scientists have learned about the Denisovans since they were first identified through ancient DNA analysis in 2010. “For years we knew them mainly from DNA and a handful of fragmentary fossils,” says paleoanthropologist María Martinón-Torres of the Spanish National Research Centre for Human Evolution, who was not involved in the studies. “Denisovans are no longer just a molecular ghost.” The fossils were discovered in Bianfu Cave, located in southwestern China’s Yunnan province, alongside simple tools and cut-marked animal bones. That makes the site “one of the only places yielding Denisovan remains in clear archaeological context,” says Eric Delson, a paleoanthropologist at the American Museum of Natural History who likewise was not involved in the work. In 2019, a worker employed by a local government project to reforest the site of an abandoned limestone quarry spotted a suspiciously large number of animal bones or fossils. He alerted provincial authorities and the Yunnan Provincial Institute of Cultural Relics and Archaeology, which sent a team to conduct an initial excavation. Advertisement The karst cave was full of bones. A technique that reveals when sediment layers were last exposed to sunlight suggested the dirt the remains were found in was between 134,000 and 167,000 years old. The cave’s more than 60,000 fossil fragments contained many ancient bones that looked like the genus Homo—but it wasn’t clear which ancient human group. To find out, researchers first tried to extract ancient DNA, to no avail, says Qiaomei Fu, a paleogeneticist at the Chinese Academy of Sciences’s (CAS’s) Institute of Vertebrate Paleontology and Paleoanthropology and co-author of the first Nature paper. So, the team next analyzed samples of the bones for ancient proteins—they “can be preserved for longer in environments that are not as cold” as Siberia’s Denisova Cave, she says. Five of the fossils had fragments of collagen, a common protein found in tissues throughout the body. The chemical signatures of those fragments, called peptides, closely resembled those of other fossils previously identified as Denisovans. “These five do look like they match Denisovans,” says Richard Potts of the Smithsonian Institution’s Human Origins Program, who was not involved in the research. The list of confirmed Denisovan fossils is not long: a finger bone and three teeth from Russia, a single tooth from Laos, a partial mandible from a cave in Tibet, another recovered from the sea floor near Taiwan, and a skull from northern China found in an abandoned well. Recently, scientists also reported in a preprint two partial Denisovan leg bones, a femur and tibia, dredged up by fishermen near Taiwan. But those findings left a blank space on the map of eastern Asia: southwestern China. “Bianfu Cave is the first site in this region of China where we have hominin fossils identified as Denisovan,” says Hao Li, an archaeologist at CAS’s Institute of Tibetan Plateau Research and co-author of the second Nature paper. The shape of the newly identified radius fragment, part of the elbow, suggests Denisovans had joints that would have allowed for heavy-duty lifting, like Neanderthals, but also agile movements, like modern humans, says Christoph Zollikofer, an anthropologist at the University of Zürich who was not involved in the research. The tools found at Bianfu include stone and bone flakes and scrapers, used to remove meat from bones of prey. “The toolmaking and stone working is relatively simple,” Delson says. “Knock a few flakes off so you can use them, don’t spend time making it a beautiful shape.” But Ben Marwick, an archaeologist at the University of Washington who was not involved in the research, sees evidence of complexity in the artifacts. “The Denisovans could work in multiple mediums, with both stone and bone, and were not limited by material,” he says. And although the stone handiwork may have been “expedient,” he says the faunal remains, which include deer and water buffalo, indicate Denisovans in southwestern China had a clear hunting strategy: They focused on medium to large animals, knowing “what makes a good kill—what’s worth their time and effort.”