A fossilized jawbone dredged from the seabed near Taiwan more than two decades ago has now been confirmed to belong to the elusive Denisovan species of archaic humans, marking a significant expansion of their known geographical range. The discovery, recently published in Science and spotlighted by The Nature, was made possible through the painstaking extraction and analysis of ancient proteins from the fossil, dubbed Penghu 1.
The Penghu 1 fossil, found off the west coast of Taiwan in the Penghu Channel, features a lower jawbone with four intact teeth. While researchers long suspected it belonged to a previously unidentified human relative, the lack of DNA and sediment context left its origins a mystery—until now.
Using advanced protein analysis, a team of scientists isolated fragments from the fossil and identified amino acid sequences that matched those from Denisovan remains first discovered in Siberia’s Denisova Cave in 2008. Remarkably, this is only the second time ancient proteins have directly linked a fossil to the Denisovans, following a similar identification in 2019 of a Tibetan jawbone known as Xiahe 1.
“The identification of Penghu 1 as Denisovan shows they weren’t just a high-altitude or cold-climate group,” said Janet Kelso of the Max Planck Institute, reflecting on the significance of finding Denisovan remains in a warmer, coastal region. This reshapes scientists’ understanding of where Denisovans lived and suggests a broader range of adaptation than previously thought.
The fossil’s exact age remains uncertain. Rainer Grün, a geochronologist who previously dated the jaw, notes it is “older than 50,000 years,” potentially placing it alongside the oldest Denisovan fossils, some of which are over 200,000 years old.
The geographical implications are profound. While Denisovan DNA is found in many present-day Pacific populations—one key sequence variant from Penghu 1 is present in over 20% of Filipinos—this is the furthest east that Denisovan remains have been definitively identified. Scientists believe these populations resulted from interbreeding between Denisovans and early Homo sapiens.
Molecular biologist Enrico Cappellini of the University of Copenhagen, who co-authored the study, suggests that multiple distinct populations of Denisovans likely existed, with subtle genetic differences appearing between the Siberian, Tibetan, and now Taiwanese fossils. He emphasizes that this diversity challenges previous notions about the group’s distribution and opens the door to future discoveries in places as far-flung as India or Southeast Asia.
More fossil evidence is needed to better understand what Denisovans looked like and how they lived. Promising candidates include a Denisovan-like tooth found in Laos and the massive “Dragon Man” skull from Harbin, China. According to Bence Viola, a palaeoanthropologist at the University of Toronto, the success of these minimally invasive protein techniques could prompt museums to allow further testing of archaic specimens.
As reported in The Nature, the discovery underscores the power of protein analysis in solving ancient mysteries where DNA cannot survive, and it may soon reveal an even more intricate story of our ancient cousins and their legacy in modern humans.
