Continued study of an approximately 40,000 year old finger bone from Siberia has identified a previously unknown type of human — one that may have interbred with the ancestors of modern-day Melanesian people.

The fossil scrap — just the tip of a juvenile female’s finger — was discovered in 2008 during excavations of Denisova cave in Siberia’s Altai Mountains. Anatomically, it looks like it could have belonged to a Neanderthal or a modern human. But, in an initial announcement published in April in Nature, a team of scientists led by geneticist Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology concluded the bone belonged to a distinct population of humans that last shared a common ancestor with Neanderthals and our species about a million years ago.