Nearly a decade ago, a snippet of pinky bone found in Siberia introduced the world to a baffling new kind of ancient human. Called Denisovans, after the name of the cave in the Altai Mountains where the bone was found, these ancient relatives of the Neanderthals inhabited Asia for tens of thousands of years—yet no fossil trace of them has been found save that finger bone, a few teeth, and a scrap of skull, all from Denisova cave.

A study published today in Cell adds a surprising new twist to their mystery: DNA from a large sampling of living southeast Asians suggests that the ghostly Denisovans may be not one, but three distinct kinds of human, one of which is