she is not "the missing link," a transitional creature between today's chimps and humans. This concept has been abandoned: We did not evolve from living champs or apes, but shared a common ancestor.

Nor is she this long-sought "last common ancestor." That's because she's too young; chimps and humans are thought to have diverged between 5 million and 10 million years ago. Then we went our separate ways, each taking different evolutionary trajectories.

But she's important because she is the closest we have come to this unfound "last common ancestor." She belonged to a new type of early hominid that was neither chimpanzee nor fully human.