Biogeographic patterns of belemnite body size responses to episodes of environmental crisis

Body size changes have been investigated through episodes of environmental crisis among several groups of organisms but the relative contribution of within-lineage size changes, selective extinction and origination of taxa on these patterns is still being debated. Rapid warming, anoxia, and perturbations of the carbon cycle linked with volcanic activity, as well as their impact on marine diversity are well documented for the Pliensbachian-Toarcian (Pli-Toa) boundary and for the Toarcian Oceanic Anoxic Event (T-OAE). Belemnites were a very abundant and successful cephalopod group in the Mesozoic oceans playing a paramount role in the oceanic trophic webs. Belemnites have mainly been studied …