Earliest post-Ordovician metazoan reef in South China constrained to the early Aeronian

The timing of metazoan reef recovery after the end-Ordovician mass extinction remains poorly constrained in many regions. In South China, the earliest post-Ordovician metazoan reef has been previously considered middle Aeronian in age. Here, we report a newly discovered coral reef from the Xiangshuyuan Formation at the Dulin section, Guizhou Province. Integrated carbon isotope stratigraphy and biostratigraphic data indicate that the small patch reef occurs immediately above the peak of the early Aeronian carbon isotope excursion and within the range of the conodont Ozarkodina obesa and virgianid brachiopod concentration beds. These data constrain the reef to the early Aeronian (Llandovery), making it the earliest known post-Ordovician metazoan reef in South China. Comparison with reef recovery in Baltica and Laurentia, this case provides important evidence that rebuilding of metazoan reef ecosystems was geographically heterogeneous.