GUESS WHO’S COMING TO DINNER? DIVERSITY IN PREDATORS, PREY AND PREDATION METRICS

In order to understand the long-term ecological and evolutionary history of predation, a number of quantitative methods have been employed to document the frequency, behavior, and efficiency of predation as recorded in the fossil record. At the same time however, research on modern marine invertebrate predators suggest a great variability in their feeding behaviors and the record of these predatory behaviors on shelled prey. In addition, most predation studies are not completed using a multi-taxonomic assemblage approach and thus do not adequately address variability which may occur due to changes in prey availability, composition, and abundances.

In this study, I analyze Neogene molluscs from closely-spaced stratigraphic samples collected from the Dominican Republic’s Rio Gurabo section in order to assess variability in predation metrics between paleocommunities and compare changes between the predator and prey assemblages. Samples exhibiting limited breakage and abrasion as well as great size range were selected to minimize taphonomic effects. Using an assemblage approach, I assess the variabilities that occur within short time intervals and most likely reflect fluctuations in ecological and environmental conditions.

Morphometrically and numerically, naticid species between samples were found to differ statistically and thus, one can investigate whether any concomitant differences exist in predation frequencies, prey preferences, size selectivity, and drilling site stereotypy. Between samples, there do appear to be changes in site selectivity and drilling frequency in some prey taxa. However, many metrics including Assemblage Taxon Frequency, Lower Taxon Frequency, and Assemblage Frequency are similar between samples (definitions following Kowalewski, 2002).