Dominic Stratford

The development of a new geospatial framework for the palaeoanthropological site of the Sterkfontein Caves, Cradle of Humankind, Gauteng, South Africa

Geographical Information Systems (GIS) provide an essential element in modern paleoanthropological inquiry through their ability to integrate a diverse range of data within a multidimensional spatial framework which can be used for data storage, analysis and modeling. One of the challenges of creating such a framework is the integration of legacy and new data (collected with digital technologies) at large sites with a long history of research. The Sterkfontein Caves, located in the Cradle of Humankind, is the richest Australopithecus-bearing locality in the world and has been the focus of intense palaeoanthropological research for the past 80 years. A diverse range of spatial data has been collected over this history and future integrative research necessitates the development of a unified, cohesive 3D GIS framework. In this paper we describe three phases of work undertaken to implement such a framework and discuss the next steps in its development and utilization for spatial analyses.

Patterns of craniofacial variation and taxonomic diversity in the South African Cercopithecidae fossil record

The rich paleontological record of South Africa is central in our understanding of Plio-Pleistocene mammalian evolution due in large part to the number of crania recovered. Because of the difficulty of chronometric control in many of the cave systems from which these fossils derive, extinct Old World Monkeys (OWMs) are often employed as biochronological markers, making the taxonomic identification of these primate remains particularly relevant to pursuing broader evolutionary questions relating to human evolution and faunal diversity shifts. The taxonomic relationships for the OWM fossils are reconstructed through phylogenetic systematics that rely heavily on craniodental traits. These analytical methods assume that these characters are developmentally, functionally, and genetically independent. This assumption is increasingly being questioned by analyses of extant phenotypic datasets and genetics. We statistically explored cranial variation in South African fossil papionins (n = 99) to determine whether or not extinct taxa reflect the same phenotypic covariance structure as has been reported for extant OWMs. Our results show that many of the cranial measurements are statistically significantly correlated and fail to distinguish between species or even genera of fossil papionins despite distinguishing extant species. Overall, our results suggest that these extinct OWM taxa cannot be discriminated using craniofacial measurements alone, or that the taxonomic designations, as they currently stand, are confounded. Tesla A. Monson. Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building #3140, Berkeley, CA 94720, USA. tesla.monson@berkeley.edu Marianne F. Brasil. Department of Integrative Biology, University of California, Berkeley; Human Evolution Research Center, 3040 Valley Life Sciences Building #3140, Berkeley, CA 94720, USA. mbrasil@berkeley.edu Dominic J. Stratford. School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein 2000, Johannesburg, South Africa. Dominic.Stratford@wits.ac.za Leslea J. Hlusko. Department of Integrative Biology, University of California, Berkeley; Human Evolution Research Center, 3040 Valley Life Sciences Building #3140, Berkeley, CA 94720, USA. hlusko@berkeley.edu

A Review of the Geomorphological Context and Stratigraphy of the Sterkfontein Caves, South Africa

The Sterkfontein Caves, located in the southwest of the Cradle of Humankind, Gauteng, is the world’s richest Australopithecus-bearing locality and has yielded iconic fossils like Mrs Ples (StS 5) and Little Foot (StW 573), as well as Paranthropus robustus, Homo ergaster and Homo habilis fossils and large Earlier Stone Age lithic assemblages. The cave deposits have also yielded enormous assemblages of associated fossil fauna and document over three and a half million years of landscape, environmental, faunal and hominid evolution. These fossiliferous cave deposits represent a more recent episode of a geological history spanning 2.6 Ga years, beginning with the deposition of the dolomites, to the commercial exploitation of the caves by lime miners in the early twentieth century. The location and morphology of the karst caves is a result of a combination of factors including lithological variation within the two host dolomite formations, an early karstification and infilling of the dolomites over two billion years ago and local dolomite fracturing. Vadose zone collapse in densely fractured areas has enlarged chambers and passages, and played a major role in the location and nature of the openings to the landscape. When open to the landscape, a broad range of geomorphological processes, including re-dissolution of interred deposits, creates dynamic sedimentary environments with complex stratigraphic histories. This article reviews the geomorphological history of the Sterkfontein Caves in an effort to consolidate this information as we press forward with new stratigraphic and geomorphological work at the site.

The Long-Term Conservation of the Australopithecus-bearing Member 4 Excavation Walls at the Sterkfontein Caves, South Africa

ABSTRACT The Sterkfontein Caves UNESCO World Heritage site represents one of South Africa’s most valuable cultural heritage resources and is one of the world’s most prolific palaeoanthropological sites with its fossiliferous deposits spanning the last 3.5 million years. One of the most famous fossil-bearing deposits at Sterkfontein is the 2.5 million-year-old Member 4. This is the world’s richest Australopithecus-bearing deposit and has yielded iconic fossils like StS 5 – Mrs Ples, StW 53, two partial skeletons, and two species of Australopithecus. After 80 years of research, Member 4 continues to provide crucial evidence for human origins research. Over the last 35 years, since excavation of the Member 4 started exposing the walls of the deposit, their deterioration has been accelerating. The implications of this deterioration and impending collapse are severe, not only from a palaeoanthropological perspective but also a heritage management point of view. This article focuses on our efforts to conserve the deteriorating areas of the Member 4 excavation site. The project required the development of a comprehensive set of strategies that had to be adapted to the specific requirements of the national and local heritage management agencies and remain sensitive to ongoing research programmes. The strategy developed included: multiscale integrative documentation of the exposed deposits; comprehensive, independent but cohesive stabilization of the different components of the deposit while maintaining visibility for ongoing and future research; and installation of stabilization infrastructure that could be adapted to the long-term conservation excavation plan while maintaining deposit integrity and site safety.

Cranial vault thickness variation and inner structural organization in the StW 578 hominin cranium from Jacovec Cavern, South Africa

The Sterkfontein Caves site is one of the richest early hominin fossil localities in Africa. More specifically, the fossiliferous deposits within the lower-lying Jacovec Cavern have yielded valuable hominin remains; prominent among them is the Australopithecus partial cranium StW 578. Due to the fragmentary nature of the braincase, the specimen has not yet been formally assigned to a species. In this context, we employ microtomography to quantify cranial thickness and composition of StW 578 in order to assess its taxonomic affinity. As comparative material, we investigate 10 South African hominin cranial specimens from Sterkfontein (StW 505, Sts 5, Sts 25, Sts 71), Swartkrans (SK 46, SK 48, SK 49) and Makapansgat (MLD 1, MLD 10, MLD 37/38), attributed to either Australopithecus or Paranthropus, as well as 10 extant human and 10 extant chimpanzee crania. Thickness variation in and structural arrangement of the inner and outer cortical tables and the diploë are automatically assessed at regular intervals along one parasagittal and one coronal section. Additionally, topographic cranial vault thickness distribution is visualized using color maps. Comparisons highlight an absolutely and relatively thickened condition of the StW 578 cranial vault versus those of other South African Plio-Pleistocene hominins. Moreover, in StW 578, as well as in the Australopithecus specimens Sts 5 and Sts 71 from Sterkfontein, the diploic layer contributes substantially to cumulative vault thickness (i.e., >60%). Within the comparative sample investigated here, StW 505 and Sts 71 from Sterkfontein Member 4, both attributed to Australopithecus, most closely resemble StW 578 in terms of cranial vault thickness values, tissue proportions, and two- and three-dimensional distributions. Including additional Plio-Pleistocene Australopithecus and Paranthropus crania from South and East Africa in future studies would further help establish morphological variability in these hominin taxa.

New Excavations at Border Cave, KwaZulu-Natal, South Africa

ABSTRACT New excavations at Border Cave use high-resolution techniques, including FT-IR, for sediment samples and thin sections of micromorphology blocks from stratigraphy. These show that sediments have different moisture regimes, both spatially and chronologically. The site preserves desiccated grass bedding in multiple layers and they, along with seeds, rhizomes, and charcoal, provide a profile of palaeo-vegetation through time. A bushveld vegetation community is implied before 100,000 years ago. The density of lithics varies considerably through time, with high frequencies occurring before 100,000 years ago where a putative MSA 1/Pietersburg Industry was recovered. The highest percentage frequencies of blades and blade fragments were found here. In Members 1 BS and 1 WA, called Early Later Stone Age by Beaumont, we recovered large flakes from multifacial cores. Local rhyolite was the most common rock used for making stone tools, but siliceous minerals were popular in the upper members.

The Sterkfontein Caves: Geomorphology and Hominin-Bearing Deposits

The Sterkfontein Caves , located in the south-west of the Cradle of Humankind in Gauteng is the world’s richest Australopithecus -bearing locality. The fossil-bearing cave deposits represent a more recent instalment of a history spanning 2.6 Ga, from the deposition of the karst -hosting dolomite s, to the commercial exploitation of the caves by lime miners in the early twentieth century. The location and morphology of the caves is a result of lithological variation within the two host dolomite formations, multiple and complex phases of karstification and infilling of the resultant solution cavities over the two billion years since the dolomite deposition, and consistently active local tensional joint and fault systems. Where vadose collapse has opened the caves to the landscape, a broad range of geomorphological processes has created dynamic sedimentary environments with complex stratigraphic histories.