This jawbone found in the Afar region of Ethiopia could bridge the evolutionary gap between two early human ancestors. The fossil and others like it date from between 3.5 million to 3.8 million years ago—the right time period to possibly confirm that Australopithecus afarensis (living 3 million to 3.6 million years ago) was a descendent of Australopithecus anamensis (which lived 4.2 million to 3.9 million years ago). Archaeologists hope the bones will close that evolutionary gap and give them something to jaw about.