Homo erectus traditionally includes fossils dating between 1-2 million years ago from sites in China, Indonesia, and East Africa. The discovery of new specimens from Africa and Europe has refocused scientific attention on this species, highlighting important gaps in our knowledge of the unity of this species, the attribution of particular specimens to this species, and its relation to later species, including our own. This study is a rigorous statistical examination of cranial shape using the techniques of three-dimensional (3D) geometric morphometrics. Coordinate landmark data will be collected with a Microscribe mechanical digitizer and analyzed with an array of statistical techniques. Questions that this study will address include: How is cranial shape variation in Homo erectus related to overall body size, geography, and time? Do large and small Homo erectus individuals have similar cranial shapes? Do Homo erectus individuals from Africa and Asia have similar cranial shape? If there are geographic differences in cranial shape, do these differences gradually increase with distance, or is there a sharp discontinuity? How similar are earlier and later Homo erectus in cranial shape? Over time, does cranial shape change gradually or abruptly? The answers to these questions resulting from this study will help us to better understand the place of Homo erectus in human history.
Moreover, the answers to these questions are directly related to the taxonomic placement of this set of fossils. Some authors have included them all in Homo sapiens, other in the single species Homo erectus and still others have recognized multiple species within this group. Following Mayr's biological species concept, and using models of expected variation within and between species based on modern humans, chimpanzees and Old World monkeys (as well as fossil Theropithecus baboons and Paranthropus), this study will explicity evaluate the systematic placement of these Early-Middle Pleistocene fossil humans. The results of this research will be applicable to other systematic, taxonomic and paleontological studies.
The broader impacts of this study include promotion of women in science, fostering of international collaboration, an enhanced database of geometric morphometric data, and the international transfer of geometric morphometric techniques. This study constitutes the co-PI's doctoral dissertation research; completion of this research and her doctorate will increase female representation in the sciences. This study promotes international ties and collaboration, increasingly necessary in the contemporary paleoanthropological research, which is increasingly conducted by multi-national teams. The NYCEP Geometric Morphometrics group databases all data collected by members of the group for future re-analysis and study; the data collected in this study will be added to that database. Finally, while geometric morphometric techniques are enjoying more widespread use, they are still relatively new. The co-PI will demonstrate their use during her international travels and thereby increase global scientific knowledge and build infrastructure. The results of work in human paleontology are of broad public interest and will be widely disseminated in both technical and popular publications.
