National Geographic : 2015 Oct
A New Kind of Ancestor H. naledi was much closer in appearance to Homo species such as H. erectus than to australopithecines, such as Lucy. But it possesses enough traits shared with no other member of our genus that it warrants a new species name. “Lucy” Australopithecus afarensis 3.2 million years ago Adult female Height: 3 ft 8 in | Weight: 60-65 lbs “Turkana Boy” Homo erectus 1.6 million years ago Adolescent male Height: 5 ft | Weight: 110-115 lbs Projected adult height The Sum of Its Parts A composite skeleton reveals H. naledi’s overall body plan. Its shoulders, hips, and torso hark back to earlier ancestors, while its lower body shows more humanlike adaptations. The skull and teeth show a mix of traits. SKELETON: STEFAN FICHTEL BODY COMPARISON PAINTING: JOHN GURCHE SOURCES: LEE BERGER AND PETER SCHMID, WITS; JOHN HAWKS, UNIVERSITY OF WISCONSIN-MADISON Humanesque skull The general shape of H. naledi’s skull is advanced, though the braincase is less than half that of a modern human’s. HOMO FEATURES AUSTRALOPITHECINE FEATURES Versatile hands H. naledi’s palms, wrists, and thumbs are humanlike, suggesting tool use. Primitive shoulders H. naledi’s shoulders are positioned in a way that would have helped with climbing and hanging. Flared pelvis The hip bones of H. naledi flare outward—a primitive trait—and are shorter front to back than those of modern humans. Curved fingers Long, curved fingers, useful for climbing in trees, could be a trait retained from a more apelike ancestor. Long legs The leg bones are long and slender and have the strong muscle attachments character- istic of a modern bipedal gait. Humanlike feet Except for the slightly curved toes, H. naledi’s feet are nearly indistinguish- able from ours, with arches that suggest an efficient long-distance stride.