Origination preceding extinction during late Cenozoic turnover of Caribbean reefs

Statistical analyses of occurrence data derived from new collections throug h scattered Caribbean sections indicate that increased speciation preceded a pulse of extinction during regional turnover of the Caribbean reef coral fauna in Plio-Pleistocene time. The data are based on samples that were new ly collected and identified to species using standardized procedures. Age-d ates were assigned using high-resolution chronostratigraphic methods. The r esults show that coral species with a wide range of ecological traits origi nated and were added to the species pool as much as 1-2 million years befor e extinction peaked at the end of the turnover interval. Local assemblages consisted of a mix of extinct and living species, which varied in compositi on but not in richness. Extinction was selective and resulted in a faunal s hift to the large, fast-growing species that dominate Caribbean reefs today . The unusual relationship between origination and extinction may have been caused by changes in oceanic circulation associated with emergence of the Central American Isthmus, followed by the onset of Northern Hemisphere glac iation. The pattern of origination preceding extinction may have been respo nsible for the stability of reef ecosystems during the intense climatic flu ctuations of the late Pleistocene, and for the composition and structure of modern Caribbean reef ecosystems.