IS THE TROPICAL ATLANTIC AN EVOLUTIONARY HOTSPOT FOR CORAL EVOLUTION? TIMING AND DIVERSIFICATION OF THE CORAL SUBFAMILIES MUSSINAE AND FAVIINAE IN THE TROPICAL ATLANTIC

Recent syntheses of molecular data sets with new informative morphological characters are revealing surprising evolutionary relationships among tropical reef corals, including a recent major revision of families, subfamilies, and genera. This work has major implications for systematic understanding of reef-building corals and understanding the environmental and ecological context of coral radiations. Modern species of the new subfamilies Mussinae and Faviinae are endemic to the tropical Atlantic, and make up > 50% of a total fauna. Further, they play a variety of ecological roles including massive colonial reef building species, solitary polyp forms, and free living morphologies that achieve high abundances in shallow seagrass beds. The timing of the diversification of these two families and subsequent genera and species is of significant interest, because it answers the question of whether major innovations in coral morphology and ecology occurred after the closure of the Tethys Sea in a newly forming Atlantic basin, or alternatively arose deeper in the history of corals, in a hypothesized evolutionary hotspot located in the Tethys Sea and Indian Ocean. Here, we will present a time-calibrated molecular phylogeny of these two families, sampling all species in 9 of the 10 genera. Our analysis is based on sequence data from three nuclear introns and time-calibration from the fossil record at species, and several deeper nodes.