A trove of bones hidden deep within a South African cave represents a new species of human ancestor, scientists announced Thursday in thejournal eLife. Homo naledi, as they call it, appears very primitive in some respects—it had a tiny brain, for instance, and apelike shoulders for climbing. But in other ways it looks remarkably like modern humans. When did it live? Where does it fit in the human family tree? And how did its bones get into the deepest hidden chamber of the cave—could such a primitive creature have been disposing of its dead intentionally? This is the story of one of the greatest fossil discoveries of the past half century, and of what it might mean for our understanding of human evolution. Read more This Face Changes the Human Story. But How?