DRILLHOLE PREDATION INTENSITY ON SCAPHOPODS THROUGH TIME AND CRUSHING PREDATION WITH AN EXAMPLE FROM THE MIOCENE OF THE NETHERLANDS

Reports on the predators of scaphopods are rare. Here, I present two types of predation traces on the Miocene dentaliid scaphopod Fissidentalium sp. from the Dutch Langenboom locality. The first type of predation is evidenced by drillholes produced by naticids and possibly primarily located on the middle (and thickest) part of the shell. Based on the examination of more than 700 specimens, the percentage of successfully drilled scaphopods is low with at least 1%. This is in line with the first graphical overview of drilling percentages on scaphopods through time. The second type of predation is indicated by jagged, arcuate margins found at the anterior end of a significant number of scaphopods. These breakages were not caused by pressure due to overburden. Experimental evidence indicated that breakages occur at right angles to the longitudinal axis of the shell during compression. Other post-mortem causes were ruled out because a significant number of scaphopods showed regeneration of the shell. Rather, the damages are interpreted to have been caused by decapods chipping/peeling the shell with their claws or mandibles. The predation traces suggest that Fissidentalium sp. was a shallow burrower. This research is an important contribution to the paleoecology of fossil scaphopods; it also expands the knowledge about Miocene marine food webs.