Summary and synthesis

This chapter summarizes the findings presented in the preceding chapters. To our knowledge, this volume represents the first source presenting all these fossils together in one collection. The chapters in this book provide photographs, measurements, and basic descriptions of each postcranial fossil. They present comparative observations and analyses and statistical analysis of taxonomically and functionally relevant aspects of morphology, and in some cases they provide reconstructions of the bones. Each of the chapters in this volume addresses key questions surrounding the Sterkfontein hominins. The Sterkfontein specimens share with other hominins features of the vertebral column, thorax, hip, knee, ankle, and foot indicating fully upright, human-like posture. Among many anatomical regions, though, the A. africanus fossils appear distinct from those attributed to A. afarensis, yet the variation between these samples often does not exceed that observed within single species of extant hominoids. Still, there may be evidence of more climbing behavior but also improved manual manipulatory behaviors, and perhaps a slightly different gait than typical of other hominins. Each chapter in this volume comes to a similar conclusion, that although variation in size or morphology may exceed that found in other australopith species, or even among mixed samples of other fossil hominins, the hypothesis that only one species is represented by the Sterkfontein Member 4 hominins cannot be falsified. The australopith species that “started it all” back in 1925 still has more to teach us, and we all look forward to learning what the future holds for Australopithecus africanus.