Drilling and crushing predation on scaphopods from the Miocene of the Netherlands

Reports on the predators of scaphopods are rare. This study records two types of predation traces on the Miocene dentaliid scaphopod Fissidentalium sp. from Langenboom in the Netherlands. The first type is demonstrated by naticid drillholes, located primarily on the middle (and thickest) part of the shell. Based on the examination of more than 700 specimens, the percentage of completely drilled scaphopods is low, at 1%. This is in line with the first graphical overview of drilling percentages on scaphopods through time. The second type of predation is found as jagged, arcuate margins at the functionally anterior end of a significant part of the scaphopod population. These breakages were not caused by pressure due to overburden, as experimental results indicate that such breakages form at right angles to the longitudinal axis of the shell. Reworking was also ruled out, mainly because the breakages were formed at the anterior end of the shell only. Rather, the damage is attributed to carnivorous decapods chipping/peeling with their claws or mandibles. The predation traces suggest that Fissidentalium sp. was a shallow burrower.