Is there synchronicity between brachiopod diversity changes and palaeobiogeographical shifts across the Late Ordovician mass extinction?

Abstract

As the first major biotic event in the Phanerozoic, the two‐phased Late Ordovician mass extinction (LOME) resulted in a substantial decline in marine benthic biodiversity and heralding shifts in palaeobiogeography. However, the interplay between palaeobiogeographical distribution and biodiversity dynamics during this event remains unknown. Drawing upon brachiopod occurrence data from five intervals pre‐ and post‐LOME, extracted from the Paleobiology Database, we conducted a comprehensive analysis of palaeogeographic units across the extinction event. Through examination of generic diversity, origination and extinction rates, and biogeographic connectedness, we elucidate the evolutionary trajectories of both endemic and cosmopolitan taxa throughout the extinction. Our findings indicate increased vulnerability of endemic taxa to biotic events and their aftermath relative to their cosmopolitan counterparts. Notably, we observe a concordance between shifts in the palaeogeographic distribution of brachiopods and fluctuations in their diversity during and after the LOME. Moreover, the extinction and subsequent recovery dynamics of brachiopods during this event demonstrate temporal symmetry concerning biodiversity change and palaeobiogeographic structural shifts. Shortly after the extinction event, within a timeframe similar to the decline in diversity and contraction of palaeogeographic distribution, both aspects revert to pre‐extinction levels, suggesting the limited intensity of the LOME event.