Abstract Macroboring of coral reefs has varied significantly through time, with the modern intensity and producer composition (usually dominated by sponges) as a rather recent phenomenon. Given the outstanding role and influence of bioerosion on framework morphology, community composition and sediment production, Modern conditions are therefore poor analogues for the structure and function of pre-Neogene reef systems. Modern and Neogene reef borer associations are mostly dominated by sponges, although marked spatial variations in the abundance of borer groups are evident within individual reef systems. Highest diversity typically characterizes low energy, shallow water back-reef or lagoon sites. This condition evolved gradually from the Late Triassic onwards, when scleractinians first built reefs. Sponges appear to have played a subordinate role in Mesozoic coral-dominated buildups. Worms and barnacles dominate in the early Mesozoic (Triassic and Lower Jurassic), with a progressive increase in bivalve borers through the Jurassic. The paucity of data collected to date makes determination of the causes of temporal change in macroboring community composition difficult to constrain. Macroboring groups seem to have withstood biotic crises much better than their coral substrate and thus reef ecological evolutionary units are not applicable. There is some indication that macroborers may have radiated to colonize new ecological niches during the early stages of coral reef diversification. The development was nonetheless influenced by biotic changes in the marine realm, the strongest effects potentially resulting from switches in nutrient status and the origin or diversification of reef grazers.

Abstract A survey of marine bivalve biodiversity in the Florida Keys, an island archipelago off southern Florida, was compiled from original collecting, museum specimens and the literature. Assembly of over 6000 records resulted in 325 species, 47% of which can be considered common to abundant in the Keys. This represents a 100% increase over the previously known fauna, largely attributable to critical review of museum specimens. Capture of species occurrences from the literature, especially when non-traditional sources (newsletters, agency reports) are excluded, is shown to be least effective, producing only 44% of the total. Bivalve distributions within the Keys show that the fauna is tropical. One-third of the species are wide ranging along the island chain; however, a latitudinal cline in faunal similarity exists from the Upper Keys southwestwards to Dry Tortugas. The fauna of Florida Bay is the most divergent within the study region and also compared to other, ecologically complex, western Atlantic tropical–subtropical regions. Limited historical records indicate little species turnover in the Keys, although population reductions along the main highway and habitat shifts (from natural to artificial substrata) are evident. These results have implications for biodiversity survey methods and, more locally, for management of the Florida Keys National Marine Sanctuary.