Rapid vertebrate recuperation in the Karoo Basin of South Africa following the End-Permian extinction

The mass extinction that occurred at the end of the Permian Period approximately 251 Mya is widely accepted as the most devastating extinction event in Earth’s history. An estimated 75–90% of global diversity from both marine and terrestrial realms disappeared synchronously within at most one million and perhaps as little as 100,000 years. To date, most research has focused on the marine record and it is only recently that a few fully preserved terrestrial Permo-Triassic boundary sequences have been discovered. The main Karoo Basin of South Africa hosts several well-preserved non-marine Permo-Triassic boundary sequences that have been the focus of intensive research into the nature of the extinction and its possible causes. This study uses sedimentological and biostratigraphic data from boundary sequences near Bethulie in the southern Karoo Basin to make assumptions about the rates and timing of recovery of the terrestrial fauna in this portion of southern Gondwana after the extinction event. The biostratigraphic data gathered from 277 in situ vertebrate fossils allows us to define more accurately the temporal ranges of several taxa. These data also confirm a more precise extinction rate in this part of the basin of 54% of latest Permian vertebrate taxa, followed by the onset of a relatively rapid recovery, within an estimated 40–50 thousand years (based on the calculation of floodplain aggradation rates and compaction ratios) that included the origination of at least 12 new vertebrate taxa from amongst the survivors.