Fifteen years ago, the biggest mystery of human evolution emerged from a 60,000-year-old little finger bone, and it will finally begin to be solved in 2025.
Analysis of DNA extracted from fossils shocked the scientific world in 2010 when it revealed a previously unknown group of humans who had met and interbred with our own species, Homo sapiens, in the distant past. Known as the Denisovans, this mysterious group is famous for the Denisovan Cave in Siberia’s Altai Mountains, where the pinky was found.
Although scientists have a deep understanding of the genetic makeup of the Denisovans, and millions of people today carry these traces, they know nothing about what the Denisovans looked like, where they lived, or why they disappeared. The discovery and the questions it raised inspired a generation of geneticists, archaeologists and paleoanthropologists.
Some of that work paid off this year, when scientists finally extracted new clues for the Denisovan name from another famous fossil: a prehistoric human skull that didn’t seem to match any known group. Now, other pieces of the puzzle are starting to fall into place.
View from Denisova Cave in the Altai Mountains of southern Siberia. – Zoonar GmbH/Alamy Stock Photo
DNA extracted from a little finger bone unearthed from a cave reveals the first known Denisovan. -Eddie Gerrard/Alami Stock Photo
Enter “Dragon Man”
When the skull was discovered in Harbin, northeastern China, in 2018 after being safely kept at the bottom of a well for decades, some scientists had a hunch that it might be a Denisovan.
DNA sequences from this group have been detected in the genomes of present-day Asians but not in Europeans, suggesting that this region was the main home for Denisovans.
Based on its unique shape, the researchers attributed the skull to a newly discovered species, which they called “Elongated Man” or “Dragon Man.” Since 2010, more than a dozen Denisovan fossils identified using DNA are too small and fragmented to warrant an official species name.
Retrieving ancient DNA from a skull estimated to be 146,000 years old holds the key to understanding whether there is a link between dragons and Denisovans. However, this proved tricky.
A research team led by Fu Qiaomei, a geneticist and professor at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences in Beijing, tested six bone samples from the only surviving teeth and petrous skull bones of Homo sauropods. The petrous bone is the dense part at the base of the skull that is often a rich source of DNA in fossils. However, the sample yielded no results.
But as a young researcher, Fu was part of the team at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, which first discovered Denisovans. She reported in June that her team had been able to retrieve Denisovan genetic material from an unexpected source: draconian dental calculus—the gunk left on teeth that, over time, can form a hard layer and preserve DNA in the mouth.
This information is not a sure bet. The genetic material the researchers retrieved was mitochondrial DNA, which, unlike nuclear DNA, is only inherited through the maternal line and therefore does not provide a complete picture of an individual’s genomic ancestry. This discovery could mean that draconians could be a hybrid of the two species, which wouldn’t be unprecedented. In 2018, scientists discovered a fossil in Denisovan Cave belonging to a girl whose mother was a Neanderthal and her father was a Denisovan.
However, the team also recovered protein fragments from the petrous bone samples, which, while less detailed than DNA, suggested that the Dracula skull belonged to a Denisovan.
Together, the two pieces of evidence “unravel some of the mysteries surrounding this population,” Fu told CNN in June when the study was published. “Fifteen years later, we know about the first Denisovan skull.”
Chris Stringer, a paleoanthropologist and head of human evolution research at the Natural History Museum in London, said in an email that the discovery of the DNA makes it possible that Homo elegans could become the official name for a dozen other Denisovan fossils.
Ryan McRae and Briana Pobiner, paleoanthropologists at the Smithsonian’s National Museum of Natural History, agree, although they say the name Denisovan will likely continue to be a popular name, like what most people call Neanderthals today.
“While more work needs to be done to build the body of evidence that will give scientists a more complete understanding of Denisovan anatomy, habitat and behavior, being able to link complete fossils to molecular evidence is a big step forward,” McCrae and Bobina wrote in their annual list of hot topics in human evolution.
Researchers say more evidence may already be available and awaiting confirmation, and with that evidence, 2026 could lead to more groundbreaking discoveries.
Now that there is molecular evidence linking the Dracula skull to Denisovans, paleoanthropologists can more easily identify other potential Denisovan remains, including these skulls unearthed in China. ——Zhao Guanghui
Denisovan portrait
John Gurche, a paleontologist who reconstructs ancient human ancestors for museums including the Smithsonian and the American Museum of Natural History, said fossil skulls have distinct bumps and ridges that can reveal what a person looked like. He recreated the face of the Dragon Man for National Geographic.
Scientists say that assuming the Dracula skull belongs to a typical Denisovan, ancient humans should have obvious brow ridges, large teeth, and not have our high foreheads. But if dressed in modern clothes, this prehistoric relative probably wouldn’t attract too many glances on the subway.
Gurchi said he used known relationships between soft and bone tissue in humans and apes to reconstruct facial features, such as the width of the eyeballs, the size of the nasal cartilage and the thickness of the soft tissue in certain parts of the face. Even more challenging are features of the skull that “provide little information,” including the shape of the lips and ears and the position of the hair.
Now that there is molecular evidence linking Dracula to Denisovans, paleoanthropologists will have an easier time identifying other potential Denisovan remains, including fossilized skulls from long-unclassifiable sites in China.
More revelations may come from the discovery of another skull fossil in China in 2022 that has yet to be formally described in the scientific literature. This is the third skull to be unearthed at the Yunxian site in China’s Hubei Province, believed to be about a million years old. Two other skulls were discovered in 1990.
In September, the site released a second digital reconstruction of a severely squashed skull that showed it was an early ancestor of draconians, meaning the lineage may have originated much earlier than previously thought.
A broader analysis based on the reconstruction and more than 100 other skull fossils also pushed back the appearance of species such as humans, sapiens and Neanderthals by 400,000 years.
However, the findings raise some doubts. More details about the third Unzen skull will allow the team to test the accuracy of the reconstruction and its place in the human family tree.
Scientists used digital technology to reconstruct the crushed skull. – Bai Jiannan/Ni Xijun
Oldest genome raises new questions
A 200,000-year-old tooth that looks similar to a molar still attached to a dragon hominin skull may change understanding of the Denisovan and human lineage more broadly over the next year and beyond. Researchers discovered the tooth while excavating Denisova Cave in 2020.
Stéphane Peyrégne, a researcher at the Max Planck Institute for Evolutionary Anthropology, and his colleagues analyzed the molar and recovered from it the complete Denisovan genome—a highly detailed set of genetic information that sheds light on past genetic diversity and evolution.
This is the second time scientists have sequenced a “high-coverage” genome from a Denisovan fossil – the first was from fossilized fingers that revealed the existence of Denisovans.
The scientists shared the genome analysis in October on a so-called preprint server, which allows study authors to publish early versions of their work online where it is undergoing peer review by other researchers. Peregne declined to comment on the paper until it is officially published next year. Stringer called the findings “very important.”
The genome allows further study of Denisovan biology that may affect human health today. For example, a study published in August suggested that variations in Denisovan genes involved in the production of mucus and saliva may have helped Homo sapiens adapt to new environments.
The new genome is also much older than the first, allowing geneticists to delve deeper into Denisovan history and reconstruct the relationships between different ancient populations.
The genome represents a small group of Denisovans who lived in Denisovan Cave 200,000 years ago. The team’s analysis revealed that not only did his ancestors clearly interbreed with early Neanderthals, but the man also had ancestors from an unknown “super-ancient” group for which there is currently no ancient DNA match.
Traces of these “ghost lineages” have also been found in the DNA of modern humans, but scientists aren’t sure who they are, said the Smithsonian’s McRae. They may represent other extinct humans, such as Homo erectus or Homo floresiensis, sometimes called “hobbits.”
“Alternatively, it could represent hominins that we really don’t find in the fossil record. They are ghosts until we find something that can be traced back to them,” he said via email.
Figuring out the identity of this group will be a new mystery for human evolution experts to ponder in 2026.
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