Inferring the behaviour of predatory gastropods and their ostracod prey across the Cretaceous–Palaeogene boundary.

This article investigates predator–prey dynamics involving ostracod prey across the Cretaceous–Palaeogene (K–Pg) extinction event by analyzing 3,146 ostracod specimens from Maastrichtian and Danian strata in the Poty quarry, northeastern Brazil. It finds that predation intensity, measured by drilling gastropod boreholes, was generally low but significantly higher in the Danian (4.7%) than in the Maastrichtian (2.7%), with a notable absence of drilling immediately above the K–Pg boundary likely due to abrupt environmental changes. The study identifies two main types of drill holes attributed to naticid and possibly muricid gastropods, with predation preferentially targeting smooth ostracod species and specific valve regions, and reveals that predator size and predator–prey size ratios increased after the extinction event. These results suggest that the K–Pg mass extinction influenced predator–prey interactions by altering predator size, prey selectivity, and ecological dynamics in marine ostracod assemblages.