The Tale of a Stray Finger Bone

Human evolution gets more interesting all the time.

A previously unknown kind of human group vanished from the world so completely that it has left behind the merest wisp of evidence that it ever existed — a single bone from the little finger of a child, buried in a cave in the Altai mountains of southern Siberia.

Researchers extracted DNA from the bone and reported Wednesday that it differed conspicuously from that of both modern humans and of Neanderthals . . .

As recently as 30,000 years ago, it now appears, there were five human species in the world: Homo erectus, the little Floresians, Neanderthals, modern humans and the new lineage from the Denisova cave.