Naticid gastropod predation on bivalve assemblages across the K-Pg mass extinction boundary in Rajahmundry, India

Traces of drilling predation by predatory gastropods primarily have been reported from the Cenozoic invertebrate fossil record. Cretaceous records of drilling predation on molluscan prey are limited and they showed that predation intensity was also low. Here, we provide a quantitative estimation of the naticid gastropod drilling on the bivalve assemblages from the upper Maastrichtian and lower Danian horizons of Rajahmundry, southern India. The study is based on numerous (N = 2100) bivalve specimens from the Maastrichtian and the predation intensity is estimated to be moderately high (15.3) in comparison to the global database. Among the bivalves, there was taxon selectivity. The site and size selectivity of the gastropod predation were not, however, well established. Incomplete and multiple drill holes were rare. We also assessed the impact of the K-Pg mass extinction on predator-prey interaction by studying the Danian bivalve assemblage from the same locality and found that the predation intensity drastically fell soon after the mass extinction. This indicates that during the K-Pg mass extinction event not only many taxa became extinct, but the tempo of the drilling predation was also affected.