Biodiversity patterns across the Late Paleozoic Ice Age
“The alternation of cold and mild phases during the Late Paleozoic Ice Age (LPIA; 372 – 254 million years ago) led to changes in the composition of animal life. We analyze how the diversity of lamp shells (brachiopods), snails (gastropods), and bivalves (clams, scallops, mussels, etc.) changes throughout the LPIA. In general, brachiopods were more diverse than gastropods and bivalves, but the rates of extinction and origination are similar in all three groups. With regard to environmental factors, most taxa favored deeper marine and reefal settings. Siliciclastic sediments were favored, while grain size of the sea floor sediments was less important. Origination and extinction patterns are similar in different environments and when all environments are grouped together. Our results support that the fauna was well adapted to changes throughout the LPIA. Sea-surface temperature was not the main force driving changes in faunal composition. Since the patterns of faunal change are similar in different environments, we conclude that the habitat was of minor influence.”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.” >> PaleoElectronica Article