Fossil hunters have confirmed the richest cache of Denisovan remains found outside Siberia's Denisova Cave, filling a long-standing geographic gap in the record of one of humanity's most elusive extinct relatives. Two studies published Wednesday in Nature describe five hominin specimens recovered from Bianfu Cave in China's southwestern Yunnan province, including the first Denisovan forearm bone ever identified.
The specimens — two skull fragments, a radius, and two teeth — were pulled from more than 60,000 fragmentary bones excavated at the site, using a proteomic screening method called zooarchaeology by mass spectrometry, or ZooMS, followed by deeper protein sequencing to confirm species identity. Because Denisovans are known almost entirely from a handful of bone fragments and teeth in Siberia and Tibet, and because their DNA degrades quickly in warmer climates, researchers have had to rely on ancient proteins rather than genetic material to identify remains this far south.
"Bianfu Cave lies along an important migration corridor linking the Qinghai-Tibet Plateau with East Asia, South Asia and Southeast Asia," according to the research team led by Qiaomei Fu of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, who supervised the protein analysis. The radius, cataloged as BFD771, showed a robust head and neck resembling Neanderthal anatomy paired with shaft geometry closer to that of modern humans — a mix the authors say points to distinct biomechanical adaptations among Denisovan populations.
A 120,000-year record
A companion paper dates the site's occupation to between roughly 190,000 and 70,000 years ago, using luminescence measurements from buried sand grains alongside uranium-series dating of cave speleothems and tooth enamel. "Dating a site like Bianfu Cave means reconstructing a timeline stretching back over 190,000 years, using novel techniques that measure the luminescence accumulated in buried sand grains and the natural decay of uranium in the cave speleothems and human tooth enamel," said Bo Li, a geochronologist at the University of Wollongong who led the dating work, in comments reported by Phys.org. "This site is significant because it brings fossils, technology, subsistence and environment together in one long, stratified record."
Cut marks and fracture patterns on animal bones recovered alongside the hominin remains — from deer, water buffalo and gaur — indicate the cave's occupants deliberately hunted and butchered large prey, offering rare direct evidence of Denisovan subsistence strategies rather than the anatomy alone. Two skull fragments in the assemblage were notably thick, a trait the researchers compare to the older Homo heidelbergensis lineage, suggesting Denisovans in the region retained some archaic cranial features even as their limb bones showed more derived traits.
The findings do not resolve every question about how Denisovans, who are known largely through interbreeding traces in the DNA of living Asian and Oceanian populations, related physically to their Siberian and Tibetan counterparts. But by anchoring a fifth confirmed Denisovan site — and the first substantial one in subtropical southern China — the Bianfu Cave assemblage gives paleoanthropologists their clearest look yet at how widely, and how variably, the species was adapted across East Asia.
