Biodiversity patterns across the Late Paleozoic Ice Age

Le résumé fourni par la source

The Late Palaeozoic Ice Age (LPIA, Famennian to Wuchiapingian) witnessed two transitions between ice-and greenhouse conditions.These alternations led to drastic alterations in the marine system (e.g., sea-level, habitat size, sea-surface temperature) forcing faunal changes.To reassess the response of the global marine fauna, we analyze diversity dynamics of brachiopod, bivalve, and gastropod taxa throughout the LPIA using data from the Paleobiology Database.Diversity dynamics were assessed regarding environmental affinities of these clades.Our analyses indicate that during the LPIA more taxa had an affinity towards siliciclastic than towards carbonate environments.Deep-water and reefal habitats were more favored while grain size was less determining.In individual stages of the LPIA, the clades show rather constant affinities towards an environment.Those bivalves and brachiopods with an affinity differ in their habitat preferences, indicating that there might have been little competition among these two clades.Origination and extinction rates are similar during the main phase of the LPIA, whether environmental affinities are considered or not.This underlines that the LPIA marine fauna was well adapted and capable of reacting to changing environmental and climatic conditions.Since patterns of faunal change are similar in different environments, our study implies that the changes in faunal composition (e.g., diversity loss during the LPIA; strong increase of brachiopod diversity during the Permian) were influenced by the habitat to only a minor degree but most likely by yet unknown abiotic factors.However, also sea-surface temperature was not the main force driving changes in faunal composition.

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