Pathways to humanity: Adaptive niche diversity at the origins of the human lineage

ended

For almost 100 years, the evolution of humans has been summarized as a transition from small-brained bipeds with an ape-like body plan (referred to as australopiths), to large-brained striding bipeds with a human-like body plan (members of the genus Homo). This characterisation dominates popular perception of human evolution in the public sphere. However, three newly discovered fossil human (hominin) species (H. naledi, H. floresiensis and Australopithecus sediba) do not fit this simple transitional model in either morphology or time (the former two surviving contemporaneously with modern humans), and have re-ignited debate about the origin of the Homo lineage, including perceptions of the earliest putative Homo species, H. habilis. These new fossils raise fundamental questions about the ecological niches occupied by hominins and the inferred transitions between niches throughout human evolution. With NewHuman, I will pioneer a novel, interdisciplinary and holistic approach using cutting-edge analyses of internal structures of fossil hominin teeth and bones to reconstruct the adaptive niche of these enigmatic species and test whether there is an unrecognized adaptive branch on the human family tree. Specifically, NewHuman will employ ground-breaking imaging techniques and analytical tools to reveal never-before-examined tooth and bone structures in these hominins. In doing so, it will 1) characterize the behaviour of these enigmatic species and place them more firmly into their ecological environment; and 2) elucidate the adaptive strategy that was likely the transition from australopith-like hominin species to later Homo, but which also represents a highly successful lifeway that persisted for over 2 million years alongside the evolving human lineage. By achieving these ambitious aims, NewHuman will have a significant impact on hypotheses about human evolution, and could result in a paradigm shift that overturns current views on human evolutionary history.