Isotopic Evidence for the Geographic Origin, Movement and Diet of the Hofmeyr Individual

The Hofmeyr skull is a singular and important fossil find, dating to a period in the late Pleistocene when the human fossil record is extremely poorly represented in southern Africa. However, its lack of contextual evidence is a serious impediment to a complete appreciation of the specimen, requiring that every bit of information possible be extracted from the fossil itself. Here we investigate the mobility and dietary ecology of the Hofmeyr individual by analyzing the strontium (⁸⁷Sr/⁸⁶Sr), carbon (δ¹³C), and oxygen (δ¹⁸O) isotopic composition from molar tooth enamel. We compared the former against ⁸⁷Sr/⁸⁶Sr in the parietal bone, associated endocranial matrix, and bioavailable strontium isotopes from an 80 km radius of the find location. The strontium isotope data are consistent with a scenario in which the Hofmeyr individual lived in the study area as a youth. The δ¹⁸O value is consistent with expectations for an individual from the Karoo in a cooler Pleistocene climate. The δ¹³C value suggests that most dietary carbon was from C₃ sources, with c. 15–20% from C₄ plants (grasses or sedges) and/or the animals that consumed those plants.