Macroboring of Pleistocene coral communities, Falmouth Formation, Jamaica

Coral samples recovered from the Falmouth Formation in north Jamaica, an emergent Pleistocene (Sangamonian) fringing reef complex, contain a wide range of boring morphologies belonging to the ichnogenera Entobia (7 (+1?) ichnospecies), Gastrochaenolites (2 ichnospecies), Maeandropolydora and Trypanites. Sampling from four distinct shallow-water reef biofacies permitted quantification of spatial variations in boring community composition and degree of substrate infestation. Coral samples from backreef/lagoon facies (mostly coral rubble) are characterized by diverse assemblages of borers, dominated by both sponge and "worm" borings, but with bivalve borings locally important. By contrast, shallow fore-reeffacies are dominated by sponge borings, with "worm" borings locally important and bivalve borings rare or absent. Highest rates of substrate infestation (expressed as a % of framework removed by borers) occur within lagoon/back-reef samples. Although facies constraints (especially the absence of deeper water facies) are likely to have exerted an influence on these data, broadly similar borer assemblages have been reported from both modern and other Cenozoic reef systems. The data provide a further link in what is, at present, the very poorly documented history of bioerosion in fossil reef systems.