Paper No. 25-8
Presentation Time: 8:00 AM-5:30 PM
DRILLING PREDATION IN THE LOWER WACCAMAW FORMATION AT PRINCE’S QUARRY IN SOUTHEASTERN NORTH CAROLINA
VISAGGI, Christy C.
1,
SIRIANI, Simone P.1, TORO, Matthew J.
1, HOLTZCLAW, Kathryn S.
1, ACKER, Adam S.
1, PARNELL, Bradley A.
2, DIETL, Gregory P.
3 and KELLEY, Patricia H.
4, (1)Geosciences, Georgia State University, PO Box 4105, Atlanta, GA 30302, (2)Cape Fear Community College, Wilmington, NC 28401, (3)Paleontological Research Institution, 1259 Trumansburg Road, Ithaca, NY 14850, (4)Geography and Geology, University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, ssiriani1@student.gsu.edu
Predator-prey relationships were examined among molluscan faunas in a bulk sample of the lower Waccamaw Formation collected from Prince’s Quarry near Old Dock, NC. Over 1650 specimens of bivalves and gastropods were sieved, picked, sorted, and identified by paleontology students as part of a class research project at Georgia State University. Bivalves with umbos and gastropods with apices were identified to genus level if >5mm and categorized as either fragmented or “whole” (if at least 85% of the shell was intact). The “whole” specimens (~1200 bivalves, ~100 gastropods) were organized into 5mm size bins and analyzed for evidence of drilling predation. Drilling frequencies (=DF) were determined for any genera that had over 10 individuals represented (20 shells for bivalves and 10 shells for gastropods).
Drilling predation was observed in 23 genera. Eighteen bivalve genera represented by ~750 shells yielded 84 complete drillholes. Five gastropod genera made up of ~50 shells contained 6 complete drillholes. Only 10 of the drilled genera provided sufficient numbers of specimens for determining drilling frequency. DFs for bivalves included Arcinella (14%), Caryocorbula (11%), Chama (13%), Conradostrea (7%), Glycymeris spp. (32%), Lirophora (22%), and Pleuromeris (7%). Gastropod DFs included Crepidula (16%), Olivella (14%), and Turritella (10%). Overall, DFs were 13.9% for bivalves and 5.8% for gastropods of all “whole” specimens analyzed for drilling predation.
Previous work at neighboring localities in Columbus County revealed a similar range of DFs for bivalves and gastropods from the lower Waccamaw Formation. While the majority of specimens from Prince’s Quarry have already been examined, sample processing is ongoing as a small collection of rare genera and shells from smaller size classes are still being sorted. Future analyses will investigate spatial variation in drilling predation using existing data for nearby localities as part of a broader objective focused on characterizing extinction pulses of marine faunas in the region across the Plio-Pleistocene.
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