Extinction and naticid predation of the bivalve Chione Von MüHlfeld in the late neogene of Florida

Abstract

A morphometric discontinuity between species of the bivalve Chione during a PlioPleistocene extinction in Florida suggests that the Pliocene species C. erosa was replaced by the immigrant C. cancellata. Here we show that immigration of C. cancellata into the Florida ecosystem changed the dynamics of naticid predation on Chione. Chione cancellata, upon its first appearance in Florida, exhibited no greater degree of escalation than its predecessor C. erosa. The relative size of prey selected by naticid predators, however, declined significantly. Selected prey size subsequently increased during the Pleistocene and into the Recent, but C. cancellata has responded by significantly increasing relative shell thickness. These patterns of interaction provide direct evidence for the disruption of predator-prey systems by mass extinctions, and the microevolutionary escalation of anti-predatory traits. Copyright: Paleontological Society, 15 March 1999.