Studies suggest that Pleistocene sea-level fluctuations have drastically affected shallow marine ecosystems such as coral reefs. In the Southwest Atlantic, a Seamounts chain near the Abrolhos Bank has been hypothesized as a stable climatic refugium during the Last Glacial Maximum (LGM). This refugium would have allowed recolonization of the present-day shoreline. Here, we integrated paleoclimatic simulations based on ecological niche modeling (ENM) and adopted a phylogeographic approach to assess this hypothesis for the endemic reef-building coral Mussismilia braziliensis. The niche modeling indicated that the potential distribution of M. braziliensis was smaller in the LGM than in the present; however, the predicted climatically stable regions were not located in the Victoria–Trindade seamount chain, but in regions to the north of this chain. Genetic data showed low structure for the three markers used: SRP-54, ITS, and MaSC-1. Our results suggest a scenario in which the M. braziliensis distribution probably followed the sea-level fluctuation, maintaining its latitudinal distribution range since the LGM, and that it was not confined to a reduced climatic refugium, as previously imagined. We highlight the pioneering nature of this study by combining phylogeography and paleoclimate modeling in order to clarify historical processes that resulted in the current scleractinian biodiversity of Brazilian reefs. |
