It has previously been thought that there was a steep Cretaceous and Cenozoic radiation of
marine invertebrates. This pattern can be replicated with a new data set of fossil occurrences
representing 3.5 million specimens, but only when older analytical protocols are used.
Moreover, analyses that employ sampling standardization and more robust counting
methods show a modest rise in diversity with no clear trend after the mid-Cretaceous.
Globally, locally, and at both high and low latitudes, diversity was less than twice as high in …