This dataset comprises lists of fossil species from a polar region (Seymour Island, Antarctic Peninsula) and two tropical regions (Western Europe and US Gulf Coast) during the Early Cenozoic era. The dataset begins in the Late Maastrichtian epoch of the Cretaceous period, extends across the mass extinction event at the Cretaceous/Paleogene (K/Pg) boundary, and terminates in the late Middle Eocene (i.e., a timespan of some 30 Myr from approximately 70 to 40 Ma ago).

The lists are based on four of the commonest types of fossil found at the time: two of these are bivalve molluscs and two are gastropod molluscs. Within each group (or taxonomic clade), the fossils are listed by family, starting with the taxonomically most primitive and ending with the most recent (or derived). Both genus and species names are given. The data were collected in various stages between 2009 and 2021.

These lists were used to compare patterns of mass extinction across the K/Pg boundary and then subsequent evolutionary radiation of these four groups through the first 25 Myr of the Cenozoic era. Full details of this study are given in: Crame, J.A. & McGowan, A. J. In press. Origin of the tropical-polar biodiversity contrast. Global Ecology and Biogeography.

This project was funded partly through NERC grant NE/I005803/1 and partly through BAS/NERC core funds.