Differential infestation of shallow-water benthic foraminifera by microboring organisms; possible biases in preservation potential

Microborings are found in virtually any exposed carbonate substrate in the tropi- cal waters of the Bahamas. Previous investigations of microborers have con- cluded that substrate type plays little or no role in their distribution. However, our preliminaiy scanning electron micro- scope (SEM) study of microboring casts in six common genera of foraminifera from San Salvador island demonstrates that host taxa differ with respect to extent of infestation and location of infestation within the test. We suspect, but can not yet prove, that different assemblages of microboring organisms are also in- volved. The primaqy differences exist at the suborder level; members of the Suborder Rotaliina are not as bored as specimens of the Miliolina taken from the same sample. Rotaliids are infested almost exclusively in the outer margin of the test, whereas miliolids vary from taxon to taxon. Differences in infestation at the suborder level may be controlled, at least in part, by the fundamental differences in wall microstructure between the Rota- liina and the Miliolina, and may have important implications for their relative preservation potentials.