THE POSTHUMOUS LIFE OF CERION

Cerion,a terrestrial gastropod that is ubiquitous on many Caribbean Islands, has figured prominently in evolutionary studies and Bahamian biostratigraphy. The dead, empty shells of Cerion,however, also provide a wealth of information in regard to ecological/environmental factors (i.e., predation, type of shell-inhabitant, habitat) associated with the snail during life and then, in death. Examination of live and dead Cerionshells from various Bahamian islands indicate that ecological factors preserved on their shells are strongly habitat-dependent and may be related to island size. That is, on large islands, inland Cerionshells have low frequencies of shell repair (up to 0.22) and low frequencies of land-hermit-crab inhabitation, whereas open-coastal sites had high frequencies of shell repair (up to 0.74 in some localities) and land-hermit-crab inhabitation (up to 0.90 in some localities). Ecological factors preserved on Cerionshells from small islands or cays were most similar to open-coastal sites because true inland habitats were rare. Additionally, kill sites representing regurgitated remains of land hermit-crab-occupied Cerionshells by the Yellow Crown Night Heron (Nyctanassa violacea)were also common in open, coastal habitats. Cerion,then, is attacked not only while alive, but posthumously as well if its shell is inhabited by a land hermit crab. Therefore open coastal settings appear to be quite ecologically complex and dynamic for modern Cerionshells; and fossil Cerion,present in coastal eolianites to 125,000 years ago, have a much higher likelihood of retaining this important ecological information. This is a boon, as the body fossils of the crabs and birds are rarely, if ever, preserved in eolianites. Thus, only the Cerionshells may retain their predatory legacy.