LAUSR

The recent discovery of additional hominin footprints at Laetoli (Masao et al., 2016) offers a rare opportunity to revisit the biomechanics of bipedalism in early hominins, a trait that was a defining event in the evolution of the human lineage (Darwin,1871).While a great deal of work has explored how and why this hallmark trait evolved, recent debates have often focused on how best to reconstruct hominin biomechanics (Stern and Susman, 1983; Latimer and Lovejoy, 1989; Stern, 2000; Ward, 2002; Lovejoy and McCollum, 2010). Specifically, researchers have examined whether early hominins used energetically economical human-like mechanics, characterized by generally extended hindlimb joints throughout a step, or whether they used a form of bipedalism that fell somewhere between human and more flexed-limb chimpanzee-like bipedal mechanics (Stern, 2000; Lovejoy and McCollum, 2010). While much of this debate has revolved around analyses of fossil skeletal elements, ancient footprints provide another avenue to test models of hominin locomotion. Due to their age and the rarity of fossil prints, the Laetoli footprints, dated to 3.66 Ma and usually attributed to Australopithecus afarensis, have played a key role in discussions of the evolution of hominin bipedal