THE IMPACT OF TAPHONOMY ON ESTIMATING REPAIR SCAR FREQUENCY

Repair scars, which form when prey organisms are sublethally damaged during predatory attacks, are a valuable tool for interpreting both the Recent and fossil records of predation. Both Recent and fossil shells are rarely pristine and often show varying degrees of post-mortem taphonomic damage. If taphonomic damage results in a loss of information from repair scars, then more careful assessment and possible exclusion of samples will be necessary in paleoecological studies.

The goal of this study was to determine the extent to which the taphonomic processes of bioerosion, encrustation, and dissolution inhibit the recognition of repair scars on marine gastropod shells. Multiple Recent samples from populations of Littorina littorea were examined and scored for both taphonomic categories and repair scar frequencies. Shells were also experimentally exposed to both slightly acidic waters (representing normal ocean pH) and tumbled in a rock tumbler to simulate tumbling in the surf zone. These experimental analyses were used to gauge the degree of information loss due to taphonomic processes. Ongoing work will determine if there is a strong relationship between one or more independent variables such as bioerosion, encrustation, or dissolution and the dependent variable of number of repair scars. This research should inform sampling design and sample selection for studies incorporating repair scar analyses.