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Dryad

Data from: Heterogeneous palaeo-ecogeography of brachiopods during the Late Ordovician mass extinction in South China

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Oct 14, 2024 version files 5.55 KB

Abstract

Following the first phase of the Late Ordovician Mass Extinction (LOME), the globally distributed Hirnantia brachiopod fauna exhibited homogeneity both latitudinally and longitudinally. The uniform global paleobiogeography of the Hirnantia Fauna, solely based on occurrence data, might obscure its heterogeneous nature during glaciation. In this study, leveraging diversity and abundance data from well-sampled collections in South China, along with NMDS using the Raup-Crick measure, Network Analysis (NA), and abundance models, we unveil the paleo-ecogeography of the Hirnantia Fauna for the first time. The distribution of the Hirnantia Fauna in South China is categorized into three areas: the deep water area, the shallower water area, and the very shallow water area based on NMDS and NA. Drastically different benthic assemblages among these areas reveal diverse environmental settings, with a rough westward shallower trend and a deeper trend extending both northward and southeastward. Analysis of species-abundance models for eight well-sampled collections demonstrates different best-fitted models, suggesting competitive ecology operates in varied contexts despite common BA 3 environmental settings and close geographic proximity. While a substantial global sea level falling and climate cooling around the Katian-Hirnantian boundary plays important roles in the LOME, the paleo-ecogeography of the Hirnantia Fauna in South China is predominantly influenced by the expansion of the Cathaysian oldland and the Qianzhong uplift. The interval between the two LOME phases, marked by kinetic conditions, witnessed heterogeneous thriving of the Hirnantia Fauna.