This discovery brought to light an extinct kind of great anthropoid, which differed from the three living genera—the gorilla, chimpanzee, and orang—in having a long or dolichocephalic skull.

How could a tiny hominin with a chimp-sized brain have had such advanced behaviors? Comparing brains, the team decided, might help provide an answer. (At left, LB1's skull.) After LB1's discovery ...

The chimpanzee and human skulls are very similar as fetuses. The human skull undergoes little alteration during development, while the adult chimpanzee skull departs considerably from the fetal form.