The many shapes of diversity: ecological and evolutionary determinants of biodiversity through time

Fossil record of 58 extinct marine invertebrate groups belonging to six different animal phyla, ranging from the early Palaeozoic to the early Cenozoic was used to test six different models of biodiversity evolution by means of maximum likelihood estimation. The models reproduce familiar, long-standing hypotheses on biodiversity controls (such as adaptive radiation, Van Valen’s Red Queen, and density-dependence). For nearly 90% of the fossil clades analysed, the best model includes an early diversification phase, and increased extinction rate over time. These features are consistent regardless of whether the main determinants of species diversity in the models are ecological or evolutionary. Clades terminated by mass extinctions did not have shorter duration than other clades but were characterized by earlier divergence and greater species richness than other clades.