A Middle Jurassic <scp> <i>Liostrea birmanica</i> </scp> Shell Bed From the South Qiangtang Basin, North Tibet, China

ABSTRACT The Qiangtang Basin, Tibetan Plateau, is a Mesozoic marine basin characterised by well‐developed Jurassic marine sedimentary systems. The South Qiangtang Basin, being closer to the Bangong‐Nujiang suture zone, exhibits more localised and complex Jurassic strata compared to the North Qiangtang Basin. This study focuses on the Middle Jurassic 114 Daoban Formation in the South Qiangtang Basin, which consists of marine siliciclastic and carbonate rocks with abundant bivalve fossils, particularly Liostrea birmanica . We analyse the taxonomy, shell microstructure, and palaeoecology of L. birmanica . Based on its shell morphology and sedimentary context, we suggest that L. birmanica adopted a reclining lifestyle on soft substrates, representing an adaptation to soft substratum environments. The microstructure of the shells, composed mainly of irregularly foliated layers, distinguishes Liostrea from morphologically similar genera. The occurrence of monospecific shell beds of L . birmanica across a broad area suggests their potential as regional marker beds for refining the Jurassic stratigraphic framework in the South Qiangtang Basin. This research contributes to a better understanding of the palaeoecology and biostratigraphy of Jurassic marine systems in the Tibetan Plateau.