Additional Ardipithecus ramidus Fossils Studied

CLEVELAND, OHIO—Science News reports that a collection of Ardipithecus ramidus fossils, including 42 from the lower body, two jaw fragments, and a large number of teeth, have been discovered in Ethiopia’s Gona Project area, about 60 miles from the spot where 110 fossils from the same species were first discovered in the 1990s. At the time, an examination of the remains of one individual, who was dubbed “Ardi,” concluded that she walked with an upright gait. Among the recently discovered fossils, which are estimated to be between 4.8 and 4.3 million years old, Scott Simpson of Case Western Reserve University and his colleagues found the bones of an individual equipped with ankle bones that may have provided better support for its legs and trunk than Ardi is thought to have enjoyed. This hominin found at Gona also had a big toe that would have propelled its stride, Simpson explained. All of the A. ramidus individuals, however, are only thought to have been able to walk slowly over short distances. They also shared traits such as skeletal features that made them capable tree climbers, flat feet, and grasping, opposable toes. Simpson and his colleagues suggest the possible improvements in walking ability seen in the A. ramidus fossils could link them to the evolution of Australopithecus species, and the earliest known evidence of a human-like gait, some 4.2 million years ago. For more, go to “Cosmic Rays and Australopithecines.”