Recovery pattern of brachiopods after the Permian-Triassic crisis in South China

In South China, the Changhsingian brachiopods are extraordinarily abundant and diverse, comprising 468 species in 144 genera. However, approximately 91% of brachiopod species were eliminated during the Permian-Triassic (P-Tr) mass extinction event. Brachiopods in the aftermath of the P-Tr mass extinction were extremely rare, with only one opportunistic taxon, Lingulida, occasionally found in the Griesbachian and Smithian at a high abundance. Species-diversity of articulated brachiopods in the early Griesbachian, late Griesbachian, Dienerian, and Smithian are 35, 3, 2, and 0, respectively. Although a few of Mesozoic-type species occurred in the Griesbachian, Dienerian and Smithian, a marked diversification of brachiopods occurred in the Spathian and early Anisian and was characterised by 9 and 17 Mesozoic-type species, respectively. The diversification of brachiopods in the Spathian and early Anisian coincides with the contemporaneous expansion of the refuge zone, suggesting that the improvement of marine environmental conditions (e.g., lethally hot temperature and anoxic seawater) played a key role in brachiopod recovery after the P-Tr mass extinction.