Heritage Cases

Aim/rationale: The study of Permo-Triassic tetrapods (approximately 260-135 mya) from the South African Karoo Basin using cutting-edge computerised X-ray tomography, synchrotron scanning and 3D modelling has shed new light on their previously out-of-reach behaviour, biology, sense organs, neurology and physiology. This has helped resolve long-standing questions such as the evolutionary origin of hair, lactation, endothermy (“warm-bloodedness”), parental care and social complexity (Araujo et al., 2022; See Benoit et al., 2023 for a review). These works provocatively suggest that these advanced traits evolved dozens of millions of years before the origin of mammals and dinosaurs. However, the mining of this new wealth of data is hindered by technical limitations. Most prominently, most of the South African Karoo fossils are notoriously challenging to X-ray because they often contain opaque metallic crystals and nodules (Fig. 1). Fortunately, neutron scanning has proven an effective way to acquire CT data from such challenging fossils (Schillinger et al., 2018). Here, we propose to neutron scan at Dingo four Karoo fossils that will add up to the growing body of research that is revolutionising our understanding of the rapidly changing Permo-Triassic ecosystems of southern Gondwana. The aim of this research project is to neutron scan four specially selected tetrapod fossils that have the potential to answer some important research questions. Their skeletal elements and internal structures will be digitally segmented to recreate their anatomy in 3D. The fossils will then be fully described and studied, their skeletons and phylogeny reconstructed, and the biological and physiological implications discussed. The specimens include: BP/1/8010 and SAM-PK-K011795, two complete skeletons of small parareptiles; BP/1/8740 from the mid-Permian of South Africa, which is a very small herbivorous anomodont that preserves a partial skeleton with a skull; and BP/1/8500, which was found nearby BP/1/8740 and comprises a complete skull of a medium-sized herbivorous anomodont that is likely a species new to science. Specimens BP/1/8010 and SAM-PK-K011795 are parareptiles, an early group of amniotes that was likely involved in the ancestry of turtles (Bever et al., 2015). Detailed 3D comparison of their anatomy will prove pivotal in deciphering the evolutionary origins of this group. Specimen BP/1/8500 is too large and distinctive to belong to a known species of mid-Permian anomodont. It is thus likely a species new to science that needs to be described and published. In addition, it was found alongside BP/1/8740 which coincidentally is the smallest herbivorous anomodont from that time. The study of these two specimens will shed light on how anomodont body size became so diverse so early in their evolution, and what drove these adaptations. Finally, all three Permian specimens come from a new fauna, and their description will add up to the definition of a new vertebrate biozone. Methodology (short): Following discussion with the local contact, specimens BP/1/8010 (13x11x2cm), BP/1/8740 (10x10x4cm) and SAM-PK-K011795 (21x14x10cm), will each be neutronCT scanned with a voxel size of 30 µm. Each 24h scan will comprise 1500 radiographs acquired every 0.12° as the samples are rotated, with 3 x 17s radiographs per projection. Specimen BP/1/8500 (20x17x80cm) will be imaged with a 50 µm voxel size. Due to the large sample size and attenuation, it will be scanned using a Cd-filter, which eliminates the lower-energy part of the neutron spectrum, requiring 1.5 days for configuration change, calibration and scanning. A total of 5 days are requested to complete this project. Back in Johannesburg, individual bones and the internal anatomy of the specimens will then be manually segmented, reconstructed in 3D and measured by Dr Benoit using Avizo 9 (Thermo Fisher Scientific, Hillsborough, OR, USA). The four specimens will be described in detail and compared to other species for peer-reviewed publications.