This ancient Denisovan finger bone is surprisingly humanlike

A newly described Denisovan finger fossil holds a skeletal surprise, adding to the mystery of this extinct Stone Age crowd. 

A decade ago, scientists found a tiny fragment of a fossil pinkie bone in Siberia’s Denisova Cave. That bone yielded the first known Denisovan DNA and helped identify the hominids (SN: 8/30/12). Now paleogeneticist E. Andrew Bennett of Paris Diderot University and colleagues say they’ve identified the rest of the finger bone, which comes from the right hand of a roughly 13-year-old female Denisovan. 

Unexpectedly, this ancient digit looks more like corresponding bones of ancient and recent humans than of Neandertals, the scientists report September 4 in Science Advances. 

Yet Denisovans, who inhabited parts of Asia from around 300,000 to 50,000 years ago, had closer genetic ties to Neandertals than to Homo sapiens (SN: 5/1/19). The new finding raises the possibility that other yet-to-be-found Denisovan body parts may be largely humanlike. (Aside from the finger, only teeth, a partial jawbone and part of a braincase have been found so far.) As a result, Bennett’s team recommends caution in trying to identify Denisovan fossils based on shape alone.

Russian scientists unearthed the newly identified finger fossil in 2008 in Denisova Cave. Then they cut the specimen into two the next year and sent the pieces to separate DNA-research teams. Bennett’s group matched mitochondrial DNA extracted from one finger segment to mitochondrial DNA already taken from the smaller Denisovan finger fragment, indicating that the bones came from the same individual. Mitochondrial DNA is typically inherited from the mother.

In comparisons with Neandertal and H. sapiens specimens, the dimensions and shape of the entire Denisovan pinkie bone fell within the range of measures for ancient and modern humans, not Neandertals, the researchers say.