Patterns of drilling predation in relation to stratigraphy, locality and sieve size: Insights from the Eocene molluscan fauna of the Paris Basin

Predatory drilling traces are routinely used to evaluate temporal patterns in animal behaviour. However, for testing such trends it is important to consider natural and methodological variability that may play a role in shaping drilling patterns. The present study attempts to test this notion by evaluating the drilling patterns of the molluscan fauna in relation to stratigraphy, locality, sieve size (4mm, 2mm, 1mm) and taxonomic affinity at class level. We studied drilling predation using molluscan specimens from three localities (Grignon, La Ferme de l'Orme, Fleury-la-Rivière), representing a variety of elementary depositional sequences (EDS) from the Middle Lutetian strata of the Paris Basin. The overall drilling frequency (DF) averaged over the three localities is 17%; bivalves show a significantly higher overall DF (18%) compared to gastropods (14%) and scaphopods (