The late Middle Pleistocene upper third molar from Florisbad: Metrics and morphology

In the early 1930s an upper right third molar (M³) together with a calotte and fragmented facial bones of an adult fossil hominin was recovered during excavations at Florisbad. The M³ is one of the few well-dated teeth associated with cranial remains from the late Mid-Pleistocene in southern Africa and as such provides a valuable addition to the fossil dental record of this region. Here we provide a detailed description of the tooth based on standard measurements and 3D images derived from high resolution micro-high resolution micro-focus X-ray tomography. Our results show that the Florisbad M³ falls within the size range of African Homo erectus. It is slightly larger than other peri-contemporary M³s known from Africa that date from the Middle to Late Pleistocene. Like them, however, it also falls within the size range of recent, large-toothed African populations. These results suggest the maintenance of selective pressures favouring large teeth in some African populations until the present.