Scientists say fossils found deep in a South African cave reveal a new member of the human family tree.

Lee Berger, who led the expedition, told reporters Thursday the creature is named Homo naledi (nah-LEH-dee).

Paleoanthropologist John Hawks said the creature shows a surprising mix of human-like and more primitive characteristics. It may be an early member of the evolutionary group that includes modern people and our closest extinct relatives.

The fossils came from at least 15 individuals. Scientists don't know how old they are, and experts said that makes it hard to assess the significance of the find.

Another mystery is how the bones found their way into the chamber of the cave. One possibility is that the room was repeatedly used to dispose of bodies.