Latitudinal patterns of gastropod drilling predation intensity through time

Despite an expectation that predation pressure decreases with increasing latitude, studies on latitudinal variation in gastropod drilling predation through space and time have revealed equivocal trends. Here, we study the latitudinal pattern of gastropod drilling predation from the late Early Cretaceous to the Pleistocene based on a new compilation of global data on mollusks mostly from the northern hemisphere. The study finds a mid-latitudinal (i.e., 21-40 degrees ) peak in drilling predation intensity during the Miocene (the only time interval with sufficient data from all latitudinal bins), and a possible mid-latitudinal peak during the Cretaceous. For the Eocene, Pliocene, and Pleistocene the middle-and either the lower or higher latitudinal-bins show the highest drilling intensity, therefore suggesting a much flatter latitudinal gradient in drilling predation pattern; the Paleocene and Oligocene lack sufficient data for statistical comparison. The Miocene mid-latitudinal peak remains almost unchanged when analyses are restricted to certain ecological and taxonomic groups. Different abiotic (e.g., temperature) and biotic factors (e.g., generic abundances of the predatory gastropods) alone cannot explain the observed trend. The area of shallow shelf might have played a positive but statistically insignificant role in determining the observed pattern.