PREDATION ON IRREGULAR ECHINOIDS (EOCENE) FROM THE CASTLE HAYNE LIMESTONE, ATLANTIC COASTAL PLAIN (SOUTHEASTERN NORTH CAROLINA)

Analysis of the rich echinoid fauna of the Eocene Castle Hayne Limestone has yielded evidence of predation on irregular echinoids. The predators are probably members of the family Cassidae, which prey on modern echinoids. Molds of the cassid genus Phalium are reported in the Castle Hayne Limestone from the localities collected. Collections of approximately 800 specimens made from the Martin Marietta Rocky Point and Castle Hayne quarries in the Castle Hayne Limestone are dominated by the irregular echinoids Echinolampas appendiculata, Rhyncholampas carolinaensis, and to a lesser extent Euhodia rugosa rugosa. These collections have yielded specimens with holes on the test similar to those described by Gibson and Watson from the Eocene Ocala Limestone of Florida. These holes are presumed to be predatory in nature and not taphonomic. Preliminary results show a rather low drilling frequency of between 5 and 10%. The borings occur on both the oral and aboral surfaces of the test. The borings are predominantly circular in shape and are perpendicular to the surface of the test. All marks that are considered predatory are not associated with any other marks and usually occur in an area of the test that has not been altered by taphonomic effects. The Paleogene record of echinoid predation can be used to test hypotheses of predator-prey evolution previously developed for other groups of drilling gastropods.