DRILLING PREDATION IN MOLLUSKS FROM THE LOWER AND MIDDLE MIOCENE OF THE CENTRAL PARATETHYS

Drilling predation is among the most studied biotic interactions in the fossil record, and its overall patterns are well established on Cenozoic mollusks from North America. Few studies have examined such predation in Europe, which experienced a different geologic history. This study aims to evaluate taxonomic and environmental effects on molluscan drilling intensities from the Miocene of the Central Paratethys using drill frequency (DF) and prey effectiveness (PE), a measure of prey's ability to survive predatory attacks. 166 bulk samples from Austria and Slovakia that included 39,234 whole shells from the Karpatian (upper Burdigalian) and Badenian (Langhian and lower Serravallian) showed that at the level of stages, environments and localities, DF and PE were always below 10% and were slightly higher in bivalves than gastropods. Predation intensities from the Central Paratethys are therefore distinctly lower than those of other Miocene seas and it is hypothesized that this is explained by the rarity of naticid and muricid gastropods in the study area. The underlying factors controlling abundances of these drilling predators in the Central Paratethys could be related to the complex paleogeographic history of this inland sea. Intertidal DFs and PEs increased temporally, but differences in sublittoral DFs were not significant and PE values decreased significantly. Temporal patterns in DF and PE are influenced by disparities in sampled environments between the lower and middle Miocene. In general, comparisons of DFs across environments within the Karpatian and Badenian yielded similar results using higher and lower taxa. In contrast, such comparisons of PE were dependent upon taxonomic resolution.