Patterns of brachiopod faunal and body-size changes across the Permian−Triassic boundary: Evidence from the Daoduishan section in Meishan area, South China
Abstract New analysis of Permian–Triassic brachiopod assemblages and body-size changes in South China provides insights into the process of the environmental crisis in the lead up to the end-Permian mass extinction. The recently discovered Daoduishan section of South China can be considered as an important auxiliary section for the study of brachiopods at the Meishan Section D of South China, the GSSP of the Permian–Triassic Boundary (PTB). This paper studied changes of the brachiopod assemblages and body sizes through the upper part of the Changxing Formation and basal Yinkeng Formation of Daoduishan. The results show that significant changes of brachiopod assemblages took place between Beds 24e and 26. Brachiopods?Prelissorhynchia sp. and Paracruirithyris pygmaea are the dominators in Beds 14–24e, while Tethyochonetes pigmaea and Paryphella spp. are the dominators in Beds 26–29. Body sizes of brachiopods significantly decreased between Beds 24e and 26 and then maintained smaller means in Beds 27–29. Studies of brachiopod morphological features indicate both Tethyochonetes and Paryphella had advantageous adaptations enabling them to copy with living in an anoxic/dysoxic and/or low-productivity environment during the Permian–Triassic crisis.