From the field to the synchrotron, investigating the early Triassic recovery fauna from Driefontein, South Africa

The Karoo Supergroup of South Africa contains extremely rich palaeontological record, including evidence of the largest mass extinction in history, the end-Permian extinction (±251.9 Ma). The recovery of terrestrial ecosystems from this mass extinction is an active area of research and one of South Africa’s most important contributions to the field of palaeontology. The farm Driefontein 11 in the Free State Province preserves an Early Triassic (upper Olenekian) fossil lagerstattë in the Burgersdorp Formation of the Karoo’s Beaufort Group . Driefontein yields tens of thousands of body and trace fossils. These fossils range in size from sub-mm scale teeth and invertebrates to bones of large temnospondyls and archosauromorphs. Despite the importance of these fossils, the fauna of Driefontein remains incompletely known – reflecting the sheer numbers of specimens (+- 30 000 coprolites alone) as well as the fragmentary and/or fragile nature and microscopic size of many of the remains. Here, we use a multiresolution (42µm to 1.14µm) approach with propagation phase contrast X-ray synchrotron micro computed tomography on the newly installed beamline, BM18, at the European Synchrotron and Radiation Facility, to investigate all trophic levels of Driefontein. We use this large dataset of high-resolution scans to investigate various aspects of organismal biology, including growth history, functional morphology, and comparative anatomy. This study contributes to our knowledge of the recovery of terrestrial ecosystems after the largest mass extinction in history, the end-Permian extinction, and highlights the importance of Driefontein 11 as a site for future research in the field of palaeontology