Middle Man
According to its discoverers, A. sediba's odd blend of primitive and modern traits make it an intriguing candidate for the immediate ancestor of Homo. "It's the ultimate look at a species in transition," says paleoanthropologist Lee Berger. "And it's transitioning toward humans."
SOURCES: LEE R. BERGER, UNIVERSITY OF THE WITWATERSRAND; DARRYL DE RUITER, TEXAS A&M UNIVERSITY