The time interval between 4 and 3 Million years ago is the Australopithecus era. It is a period that witnessed important events in human evolution including the advent of a more habitual bipedal locomotion, the emergence of stone tool use and a shift from a tree based diet (C3) to a more grass based diet (C4).
Our team has played a pioneering role in advancing our knowledge of these major transitions using field and laboratory research. The ensuing interval of 3 to 2 Ma is believed to have been characterized by events relating to the emergence of the genus Homo; however, this major claim sits on shaky grounds primarily due to the paucity of the fossil record. Furthermore, although the Afar sedimentary basin is a hotspot for the study of human origins, the time interval in question is not well represented. We know Australopithecus afarensis ceases to exist after 2.9 Ma and yet it is not clear what came after it, notwithstanding claims made on the existence of Homo at 2.8 based on fragmentary evidence. Consequently, a key evolutionary question, i.e. the transition from Australopithecus to Homo remains essentially unanswered as are the underpinning paleo-environmental and paleo-ecological factors that drove that transition.
The Mille-Logya site provides us with the opportunity to tackle these issues as it contains sediments dated to the 3 – 2 Ma. Our preliminary fieldwork has already shown that the site contains hominin remains associated with diverse fauna. Building on this, we aim to explore this poorly known time horizon in order to reconnoiter the patterns of evolution from Australopithecus to Homo. Future hominin discoveries will also allow us to test if Australopithecus afarensis existed after 2.9 Ma or whether the first appearance datum for Homo is earlier than what it is now.