Heritage Cases

Gorgonopsians were the dominant carnivores of the late Permian (Lopingian) but reportedly became extinct at the Permian-Triassic (P-T) boundary, 252 million years ago. However, NMQR 389 has been reportedly found in the Lystrosaurus Assemblage Zone and is thus younger than the P-T boundary. We propose to use Synchrotron X-ray computed microtomography in order to confirm identification and collect clues about the taphonomic history of this specimen. In parallel, we will relocate the original site where it was found to confirm its stratigraphic provenance and address if it is reworked from underlying late Permian strata. If the occurrence of early Triassic gorgonopsians is confirmed, this would support the hypothesis of a protracted end-Permian extinction of Karoo faunas initially proposed by King (1991) and recently resurrected by Viglietti et al. (2021). If disproved, we will be in capacity to safely remove these anomalous data points that have been incorrectly influencing every large-scale analysis of Karoo faunal changes and biostratigraphy since the 1970s (see, e.g. Nicolas and Rubidge, 2010). This specimen will be mounted in a plastic tube and will be scanned using white beam propagation phase contrast X-ray microtomography (PPC-SR-uCT) at the BM18 beamline at a range of voxel sizes leading up to 200um. The scan data will be digitally reconstructed at the ESRF and analyzed in VG Studio Max 3.2 at the ESRI Facility.