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Predator/prey relationships in 40 million year old fossils from South Carolina: Latitudinal variation in drilling predation and selectivity of prey drill-hole site and prey species UNCW Undergraduate Research Fellowship Proposal Patti Mason, April 22, 2005 Acknowledgments: Thanks to Dr. Richard A. Laws and Dr. Patricia H. Kelley for their assistance and support
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Escalation (Vermeij, 1987) : states that biohazards, such as predation and/or competition increase through geologic time Vermeij looked at the fossil record of predatory snails for evidence of escalation. Predatory naticids (snails) move within the sediment to find prey and then drill through the shell and ingest the prey tissue. Background Predatory Naticid (w/ drill hole)Bivalve Prey
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Kelley and Hansen surveyed 143,000 fossil molluscs from 28 geologic formations. They found: + correlations with: Species diversity % Naticids % Preferred Prey The data showed a rising and falling of drilling frequency instead of a consistent rise, perhaps related to mass extinctions. Courtesy Kelley & Hansen, 2003
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Justification We have data from Virginia and North Carolina to the Gulf Coast states. Data from South Carolina will help fill in the gaps! Drilling Frequencies: Turritellid snails vs all snail species
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Fig. 1. Orangeburg Group (Nystrom et al, 1989) Methods 1.Return bulk sample of fossils to lab for study. 2.Tabulate location and frequency of drill holes (Drill hole frequency = % individuals with complete naticid drill-holes). 3.Measure common prey species for size, shell thickness, and internal volume for cost-benefit calculations, and any drill holes documented. 4.Test my hypotheses.
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Research Hypotheses Drilling frequencies between those for Virginia and the Gulf Coast Drill site and prey selection will be more pronounced than older assemblages Naticid predation in South Carolina predicted by cost- benefit analysis Drilling frequencies similar to those of equivalent fossil assemblages % of naticids present proportional to drilling frequency % of preferred prey proportional to drilling frequency Thank You
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