Did gorgonopsians survive the end-Permian "Great Dying"? : A re-appraisal of three gorgonopsian specimens (Therapsida, Theriodontia) reported from the Triassic Lystrosaurus declivis Assemblage Zone, Karoo Basin, South Africa
Benoit, Julien (University of the Witwatersrand. Evolutionary Studies Institute and School of Geosciences)
Kammerer, Christian F. (North Carolina Museum of Natural Sciences)
Dollman, Kathleen (European Synchrotron Radiation Facility)
Groenewald, David (Institut Català de Paleontologia Miquel Crusafont)
Smith, Roger M. H. (University of the Witwatersrand. Evolutionary Studies Institute and School of Geosciences)

Date:	2024
Abstract:	Gorgonopsians were the dominant carnivores of the late Permian (Lopingian) and it is widely accepted that the clade became extinct at the Permian-Triassic boundary, almost 252 million years ago. However, South African collections house three historically-collected gorgonopsian specimens listed as Early Triassic in age, based on their discovery at localities producing the index fossil Lystrosaurus. Initial reports suggested that these specimens had been reworked from underlying Permian strata, but this possibility was never thoroughly addressed. The possible survival of gorgonopsians into the Triassic would significantly alter our understanding of the end-Permian mass extinction and post-extinction ecosystem dynamics. Here we use Synchrotron X-ray micro-computed microtomography to confirm the identifications and investigate the taphonomic histories of these three specimens. We also relocated the original localities to determine their stratigraphic position. We confirm that all three specimens are indeed gorgonopsians, belonging to the small-bodied genus Cyonosaurus, and that taphonomic assessments do not support reworking. Two of them can be confidently assigned to the latest Permian Lystrosaurus maccaigi-Moschorhinus Subzone of the Daptocephalus Assemblage Zone. In contrast, at the locality listed for the third specimen, NMQR 389, the lowermost outcropping strata belong to the upper Palingkloof Member of the Balfour Formation, which is Early Triassic in age. Despite the evident absence of Permian-aged rocks, other Permian fossils were reported from the same locality, thus casting doubts about the age of NMQR 389. Additionally, differences in preservation style between this skull and the newly collected material at the site cast doubt on its provenance. Although not supporting gorgonopsian survival into the Triassic, these new occurrences expand the range of the genus Cyonosaurus higher up in the extinction zone, increasing the complexity of the ecological turmoil that carnivores endured during "The Great Dying".
Grants:	Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-01184 European Commission 101060666
Note:	Altres ajuts: CERCA Programme/Generalitat de Catalunya
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Published in:	Palaeogeography, Palaeoclimatology, Palaeoecology, Vol. 638 (March 2024) , art. 112044, ISSN 1872-616X

DOI: 10.1016/j.palaeo.2024.112044

Available from: 2026-03-31 Postprint

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Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut Català de Paleontologia Miquel Crusafont (ICP)
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