Cosmopolitanism of tetrapods through the Carboniferous, Permian and Triassic. Cosmopolitanism (
C) is measured as mean alpha diversity


divided by global diversity (
Tt), according to the formula


. Note the overall decline of cosmopolitanism through this time interval, perhaps related to increasing taxonomic and ecological diversity of tetrapods, but also note the coupled rises and falls in cosmopolitanism following major extinction events, especially (1) Olson's extinction, (2) the end-Guadalupian extinction and (3) the end-Permian extinction. Abbreviations are the same as given in figure legend 2.