Brachiopod faunas across the Wuchiapingian-Changhsingian (Late Permian) boundary at the stratotype section and subsurface of Changxing area, South China

Abstract

This paper describes 18 species in 15 brachiopod genera from the Wuchiapingian/Changhsingian (W/C) boundary beds at its stratotype section and subsurface succession of the Changxing areas, Zhejiang, South China. The late Wuchiapingian brachiopods of the Changxing areas are dominated by large species such as Tyloplecta yangtzeensis, Niutoushania niutoushanensis, Edriosteges poyangensis, Orthothetina ruber, and Permophricodothyris grandis. These elements also characterize the Wuchiapingian faunas across the entire South China. The early Changhsingian assemblage is dominated by the Wuchiapingian holdovers and characterized by abundant small, thin-shelled chonetides or chonetid-like productides. The W/C transition saw a change from the abundant and diverse late Wuchiapingian fauna to the restricted and impoverished assemblage in the early Changhsingian. This distinct faunal changeover may be primarily accounted by the end-Wuchiapingian regional transgression in South China. This transgression event flooded most shallow-water niches of the Changxing areas so that most of the large sessile elements suffered the loss of shallow-water habitats. In contrast, the widespread, widely adaptive opportunitists survived into the Changhsingian. The Wuchiapingian brachiopod faunas across the entire South China are comparable one another, while the Changhsingian faunas were strongly controlled by depositional settings, and both the shallow-water and deep-water assemblages are very distinct each other.