Interpreting the environments and mammal species in South Africa during the Plio-Pleistocene, including primate and human lineages, relies on a detailed understanding of the physical setting of deposition (cave geology), the distribution of mammals and environments on the landscape (paleobiology and paleoecology), and the process of converting biological materials into fossils (taphonomy). Current interpretations of the South African fossil record are largely based on deposits from the low-relief, geographically-proximate Blauubank Valley sites. However, recent research outside Blauubank has highlighted both greater biological variation in mammal communities and in geologic and taphonomic processes, warranting further excavation and analysis of novel deposits to guide our broader interpretations of the South African fossil record. This project makes a significant contribution towards understanding the factors underlying interpretations of the South Africa fossil record through two primary objectives. First, through excavation of deposits at the Hoogland and Haasgat cave systems located in the topographically high-relief Schurveberg Mountains. This represents the first comprehensive analysis of the geology of the 2-3 million year old deposits in this poorly sampled geographic region, and the animal species occupying this landscape during a critical phase in the development of modern mammal and vegetative communities. Second, systematic survey and sampling of paleontologic deposits across the Schurvebergs and transitional foothills will establish the geological and paleoecological history in this region, and be combined with data from Hoogland, Haasgat, and other South African localities to provide comprehensive interpretation of the South African fossil record.
This interdisciplinary research project makes a broader impact by training South African team members in paleontological research methods that will allow them to advance as independent scholars. Our project invests in local scientific infrastructure by expanding and modernizing paleontology laboratories at the Transvaal Museum (Pretoria), impacting current and future South African and international paleontological research. Furthermore, the general South African public will be reached through an exhibition of excavated fossils at the Transvaal Museum, highlighting the importance of local paleontology in understanding past environments and human origins.
Nearly a century of paleontological excavation into South African cave systems have allowed paleontologists to construct a critical, baseline understanding of the fossil history of South African primates and other mammals. However, deposits within these caves are calcified into a ‘natural concrete’ of sediments and fossils and it takes significant processing to recover identifiable specimens. Because of the time required to produce interpretable assemblages, past research has largely focused on the rich fossil deposits of the Blauubank River Valley sites (e.g. Sterkfontein, Swartkrans, and Kromdraai). While these sites have yielded important data they also lie very close to each other, were deposited over approximately the same time period, and were sometimes sampled with methods that favored only collecting primate specimens and teeth. As a result, and despite decades of analysis, we only have a limited (and potentially biased) understanding of the potential diversity of living and extinct mammal species on the landscape (paleobiology), past environmental conditions (paleoecology), and the cave and deposit formation processes (geology and taphonomy). This project addressed these interpretive shortcomings of the South African fossil record - and diversified our understanding of the geology, paleobiology, and paleoecology of fossil sites - through excavations at two fossil sites (Hoogland and Haasgat) outside the well-sampled Blauubank River Valley system, and completed a comprehensive GPS survey of cave systems across the high-relief Schurveberg Mountain region. Initial research our team conducted 2008-2010 at Hoogland had indicated that the rich, fragmented fossil deposits likely formed 2.6 million years ago (MYA). The continued excavation, processing and geological isotope sampling supported by this research grant has allowed us to confirm this age of the deposits. We have also greatly expanded our sample of mammals from the site, including juvenile primate and more complete remains than had been recovered during our initial excavations. Our analysis of the Hoogland mammals found significant differences in morphology and species representation from those at the Blauubank Valley sites, likely because the topographic relief of the Schurveberg region influenced the distribution of habitats, thereby the composition of mammal communities around the site. Our research activities at Haasgat included the first complete analysis of the fossils removed from the site in the 1990s and excavation of fossils across the sequence. Analysis produced the first researcher-accessible electronic database of the collections, expanded the number of identifiable primate and other mammal specimens, and led to a critical revision of the leaf-eating monkey species recovered from Haasgat (and, in fact, across the South African fossil localities). We have also generated the first full geological description of the system, with initial isotope results indicate that some of the fossils were deposited nearly 3 MYA - making them some of the oldest sampled deposits in the region. Fossil-bearing blocks excavated for this project have yielded a large sample of well-preserved specimens, greatly expanding our understanding of the biodiversity and paleoecology of the Haasgat region. The GPS survey of the Schurvebergs identified 44 geologically- and paleontologically-significant features, including four previously unknown sites with dense fossil deposits. Beyond identifying these new localties, the data collected from this survey has allowed us to establish predictive models of cave system occurence and fossil deposit formation in the region. Our integration of this landscape data with the results of our fossil analysis across the South African sites has clarified how landscape form influenced paleoecosystem development and the distribution of extinct and extant species using them. In addition to meeting our scholarly objectives this project made a broader impact by developing local paleontological resources and increasing public awareness of paleontology through outreach activities. First, we trained two of our South African team members employed at the Ditsong National Museum (Pretoria) in fossil specimen analysis. As a result, they can now more fully collaborate in research on the collections, and their expanded education on the history of South African mammal species has improved their understanding of paleontology when engaging in their public outreach activities through the Museum (including leading primary school groups). Second, we directed our fossil processing budget towards upgrading the acetic acid processing laboratory at the Ditsong National Museum. This investment in South African scientific infrastructure provides modern facilities for local and international researchers, as well as employment opportunities for additional preparators at the institution. Third, we provided direct educational outreach to the South African public through two open lectures and guided tours of fossil localities. We have also begun disseminating research articles and casts of fossil specimens to residents near the fossil sites, with the goal of establishing a central repository for the public to access without having to travel to a museum or institution. Finally, we organized an exhibition on the importance of faunal analysis, fossil preparation methods, local geology, and paleontology of the Schurveberg region that will go on public display at the Ditsong National Museum in 2012.
