Lazarus Kgasi

The first hominin from the early Pleistocene paleocave of Haasgat, South Africa

Haasgat is a primate-rich fossil locality in the northeastern part of the Fossil Hominid Sites of South Africa UNESCO World Heritage Site. Here we report the first hominin identified from Haasgat, a partial maxillary molar (HGT 500), that was recovered from an ex situ calcified sediment block sampled from the locality. The in situ fossil bearing deposits of the Haasgat paleokarstic deposits are estimated to date to slightly older than 1.95 Ma based on magnetobiostratigraphy. This places the hominin specimen at a critical time period in South Africa that marks the last occurrence of Australopithecus around 1.98 Ma and the first evidence of Paranthropus and Homo in the region between ∼2.0 and 1.8 Ma. A comprehensive morphological evaluation of the Haasgat hominin molar was conducted against the current South African catalogue of hominin dental remains and imaging analyses using micro-CT, electron and confocal microscopy. The preserved occlusal morphology is most similar to Australopithecus africanus or early Homo specimens but different from Paranthropus. Occlusal linear enamel thickness measured from micro-CT scans provides an average of ∼2.0 mm consistent with Australopithecus and early Homo. Analysis of the enamel microstructure suggests an estimated periodicity of 7–9 days. Hunter–Schreger bands appear long and straight as in some Paranthropus, but contrast with this genus in the short shape of the striae of Retzius. Taken together, these data suggests that the maxillary fragment recovered from Haasgat best fits within the Australopithecus—early Homo hypodigms to the exclusion of the genus Paranthropus. At ∼1.95 Ma this specimen would either represent another example of late occurring Australopithecus or one of the earliest examples of Homo in the region. While the identification of this first hominin specimen from Haasgat is not unexpected given the composition of other South African penecontemporaneous site deposits, it represents one of the few hominin localities in the topographically-distinct northern World Heritage Site. When coupled with the substantial differences in the mammalian faunal communities between the northern localities (e.g., Haasgat, Gondolin) and well-sampled Bloubank Valley sites (e.g., Sterkfontein, Swartkrans, Kromdraai), the recovery of the HGT 500 specimen highlights the potential for further research at the Haasgat locality for understanding the distribution and interactions of hominin populations across the landscape, ecosystems and fossil mammalian communities of early Pleistocene South Africa. Such contextual data from sites like Haasgat is critical for understanding the transition in hominin representation at ∼2 Ma sites in the region from Australopithecus to Paranthropus and early Homo.

Les primates non-humains fossiles de Bolt’s Farm (Afrique du Sud). Contexte, recherches actuelles et perspectives

RésuméLes restes d’hominidés1 fossiles sont généralement trouvés dans des niveaux géologiques contenant aussi des Cercopithecoidea. Ils ont donc partagé plus ou moins les ressources des mêmes milieux.En Afrique du Sud, la biodiversité de ces Cercopithecoidea était aussi importante qu’en Afrique de l’Est. Dans le Cradle of Humankind, il existe de nombreux sites pliopléistocènes. Bolt’s Farm est une aire fossilifère renfermant une trentaine de remplissages datés entre 4,5 et 0,9 millions d’années. Il s’agit de la plus longue séquence chronologique pour cette région. Plusieurs loci d’âges différents ont livré des restes de Cercopithecoidea. Ces découvertes sont importantes pour comprendre l’évolution de ces primates, mais aussi les relations qui ont existé entre l’Afrique du Sud et l’Afrique de l’Est et les éventuelles spécificités régionales.AbstractFossil hominid remains are generally found in association with Cercopithecoidea specimens, which gives the impression that they shared similar environmental resources.In South Africa, the Cradle of Humankind, has as much Cercopithecoidea biodiversity as East Africa, especially with the abundance of Plio-Pleistocene deposits associated with karstic geological systems found in this area. One of these, Bolt’s Farm, is a geological system representing several (circa 30) fossil-bearing deposits, ranging in age from 4.5 to 0.9 million years. The Bolt’s Farm system is the longest geochronological sequence for this area, with several deposits of different ages yielding Cercopithecoidea remains. The specimens recovered from the Bolt’s Farm system are important to our understanding of the evolution of these old-world primates, and also of the relationships that existed between South and East Africa as well as the features specific to each region.