Lucy's Place in Nature
By Prof. Yoel Rak of the Department of Anatomy and Anthropology, Tel Aviv University

Upon the discovery of Australopithecus afarensis remains in the 1970s and the subsequent acknowledgment of the remains' distinct taxonomic status, the new species was hailed as situated anatomically and chronologically "halfway" between an ape (the common ancestor of the chimpanzee and Homo sapiens) and modern humans. Furthermore, the primitive appearance displayed by A. afarensis, along with its age, rendered it an ideal candidate to be the common ancestor of modern humans and the extremely specialized robust australopith clade. Beginning in the 1990s, the intensive activity of numerous expeditions to the Hadar region of Ethiopia (site of the earlier A. afarensis finds, including the famous Lucy) filled many gaps in our understanding of A. afarensis cranial anatomy, deriving particularly from the discovery of two almost complete skulls. As a result, anatomical elements that A. afarensis shares only with the robust australopiths surfaced. This new information has forced us to move A. afarensis from its comfortable position at the bifurcation point between the robust clade and modern humans to the robust branch itself, albeit at the branch's very beginning.