THE PERMIAN EXTINCTION- JUST HOW CATASTROPHIC WAS IT?

The Karoo basin of South Africa contains the most abundantly fossiliferous succession of late Permian to middle Triassic terrestrial vertebrates yet discovered. This record can be used to test hypotheses of rate and tempo of the Permian mass extinction of land animals. We have documented a continuous record of both carbon isotopes and vertebrate occurrences across more than 100m of strata containing the P/T boundary. The pattern of both isotopic anomalies and vertebrate extinction and recovery is not consistent with a single catastrophic extinction (a K/T type mass extinction) at the end of the Permian, although this interval does show a higher extinction rate than either before or after. The isotopic and paleontological record appears to document a long environmental decline with at least one enhanced pulse of species extinction brought about by short term, antibiotic intervals. Coupled with new work in marine Permian sections, a new view is emerging of an already low-diversity biosphere undergoing a prolonged crisis. While the Permian extinction is rather uniformly regarded as the most catastrophic of all mass extinctions, perhaps this view should be tempered in light of new, emerging work.