By examining DNA extracted from dental calculus—hardened plaque—found on a skull more than 146,000 years old from northeastern China, scientists have confirmed that the fossil belonged to a Denisovan, an ancient human species. Two studies published on June 18, 2025, in Cell and Science, used different methods but reached the same conclusion. The fossil, known as the Harbin skull, had previously been considered a new species, Homo longi, or "Dragon Man," in 2021. However, new genetic and protein evidence now identifies it as a Denisovan. The DNA was extracted from the dental calculus, a mineralized form of plaque that adheres to teeth. This material is more effective than bone at preserving genetic material over long periods, allowing scientists to successfully retrieve mitochondrial DNA from the fossil. The analysis showed that the skull's DNA matches the genetic variation seen in other Denisovans and is linked to a lineage from southern Siberia, suggesting that Denisovans lived across a wide region of Asia during the Middle Pleistocene. The use of dental calculus was key, as it is harder and less porous than bone, making it better at protecting ancient genetic material. In addition to DNA, the researchers identified 95 endogenous proteins in the skull, which further confirm the individual's Denisovan origin. These proteins include three amino acid variants specific to Denisovans and align with those found in a previously studied Denisovan fossil. This data provides the most comprehensive set of ancient hominin proteins to date, offering insights where DNA has degraded over time. The discovery challenges earlier assumptions about the Harbin skull, which had been thought to belong to a new species. Denisovans were first identified in 2010 through ancient DNA found in a Siberian cave. Since then, they have been known mainly through genetic material and fragmentary fossils, leaving their physical appearance unclear. The Harbin skull, nearly complete, provides the first detailed look at a Denisovan’s face and skull structure. It features a flat face with a large nose and large molars, differing from both Neanderthals and modern humans. While the skull shares some traits with other fossils found in China, further molecular analysis is needed to confirm whether those fossils also belong to Denisovans. The Harbin skull, though confirming the individual's Denisovan identity, still leaves many questions about the full genetic makeup of this ancient group.