Carbon Isotope study of bovids - Sterkfontein

Aim/rationale:
This project presents a multiproxy palaeoecological study of fossil Bovidae and Cercopithecoidea from two Australopithecus-bearing deposits (Members 2 and 4) at Sterkfontein Caves, South Africa. A combination of proxies including ecomorphology, mesowear, hypsodonty index, and carbon isotopes will be utilized to reconstruct different aspects of the ecology. This research will build on previous efforts by investigating the palaeoecological context of Australopithecus at Sterkfontein between 3.6-3.4 Ma and to provide an improved assessment of the environment for that period. The aim of this project is to examine multiple complementary aspects of bovid and cercopithecoid ecology at Sterkfontein to provide a multifaceted assessment of the environments in which South Africa’s early Australopithecus lived. Carbon isotopes in this regard, will be employed as one of most used and reliable dietary proxies for ecological reconstruction. This will applicant hopes to collect tooth enamel samples preferably from first, second and third molars.

Methodology:
The applicant’s collection of samples will involve thorough cleaning and drying of each tooth specimen to allow the extraction of enamel powder. Enamel samples will be removed under a low-power microscope (10x 40x) where available. A rotary drill with an attached diamond grit 1.0m diameter dental burr, set to approximately 10% to 20% of maximum speed will be used to extract the samples to avoid thermal decompositions of carbonates and lessen damage to the teeth. All tools will be cleaned with 1.0 molarity (M) of hydrochloric acid and distilled water between samples to prevent contamination. The resultant enamel powder will be measured into individual 5ml microcentrifuge tubes and transported to a Stable Isotope laboratory at the University of Cape Town for pre-treatment and centrifugation and later analyzed using mass spectrometry to separate the different isotopes based on their mass-to-charge ratio. The laboratory processes and analysis (from start to finish) will be conducted by laboratory technicians under the supervision of Dr Julie Luyt from the University of Cape Town. Looking at the bovid diversity in my selected sample, I anticipate results that show mosaic dietary preferences, with more preference towards the C4 diet.