SKELETOBIOSIS THROUGH EXTINCTIONS: COMPARISON OF THE EFFECTS OF ENVIRONMENTAL CHANGE AND HOST TURNOVER ON SKELETOBIONTS BETWEEN THE LATE DEVONIAN AND END-PERMIAN EXTINCTION EVENTS

Skeletobionts (organisms that settle on the skeletal material of other organisms) are useful for paleoecological study because they are readily preserved in the fossil record, include direct evidence of biotic interaction, and can be sensitive to changes in their communities and environments. Our previous work on skeletobionts of shallow marine brachiopods in the Appalachian Basin through the Lower Kellwasser event (the first pulse of the Late Devonian extinction) suggested that the distribution of skeletobionts was most strongly controlled by environmental conditions associated with depth gradients but also responded to host body size and host sculpture to a lesser degree. Taxonomic turnover among brachiopod hosts had no apparent effect on skeletobionts, possibly because there was little functional turnover among the hosts. Therefore, comparing the fates of skeletobionts during the Late Devonian extinction with their fates during additional extinction events, especially those with marked turnover in functional traits, may tell us more about the ecological susceptibility of skeletobionts to extinction among their hosts. Extinction events in the fossil record vary tremendously in the nature of the organisms involved, the specificity of extinction, the arrangement of the continents, and the set of biogeochemical and climatic conditions present at the time. The end-Permian mass extinction provides a potentially promising case for comparison to our previous work with the Late Devonian mass extinction because it represents a time of extreme loss in diversity that is followed by functional turnover in benthic marine communities. Additionally, the end-Permian event involves many of the same groups of common skeletobionts that were present during Late Devonian time. Here, we will review what is known about the ecological effects of the end-Permian extinction and the subsequent recovery interval on skeletobionts ascertained from published literature, draw comparisons with what is known about skeletobiosis through the Late Devonian extinction, and identify unknowns for future study.