Novel insights into the end-Triassic extinction from contemporaneous southern African sedimentary basins

The end-Triassic Extinction Event (ETE) lead to the demise of ~76% of species, as well as major biotic transitions in terrestrial vertebrate faunas. These include the shift from a mainly synapsid- and pseudosuchian-dominated ecosystem in the Triassic (e.g. dicynodont and cynodont therapsids) to dinosaur-dominated ecosystem in the Jurassic. Our understanding of this crucial time in Earth’s history is hindered by the lack of sedimentary deposits that record the Triassic–Jurassic boundary and bear informative vertebrate fossils across this interval. Several southern African basins are infilled by uninterrupted Carnian–Pliensbachian sediments. These include the Stormberg Group of the main Karoo Basin of southern Africa, as well as the Mid-Zambezi and Tuli basins of Zimbabwe. Surprisingly, the paucity of the current known fossil record recovered from these southern African deposits limits their use in understanding the ETE. This is in part because, to date, the Late Triassic vertebrates known to pertain from these units are much less abundant and diverse than those from the Early Jurassic units. Over the last decade, increased field work targeting these areas, combining excavations with high-resolution dating and biostratigraphy, has yielded multiple new fossil-bearing localities that add crucial new data to our understanding of ETE faunal change. Here, I present an overview of these novel sites. One notable location includes the late Norian quarries from near the village of Qhemegha in the Eastern Cape of South Africa which preserve a diversity of vertebrates such as: large-bodied late-branching pseudosuchians; large- and small-bodied sauropodomorphs and theropods; non-dinosaurian avemetatarsalians; and synapsids.