Osmar, Josh and collaborators have had their paper about factors that shape reef fish biogeographic patterns within the Atlantic Ocean published in the Proceedings of Royal Society B [link] . Contrary to the current paradigm that dispersal on this group of fish are mainly mediated by their larval-biology, they found that adult-biology traits better explain patterns of endemism among distinct provinces. Depending on the nature of the oceanographic barrier that divides provinces, different traits determine the set of species capable of crossing it.
They analyzed the distribution of 985 tropical reef fish species in relation of two major oceanographic barriers: mid-Atlantic barrier, the large stretch of open ocean between Africa and the Americas; and the Amazon-Orinoco plume, the extraordinary freshwater and sediment discharge of those major rivers along the north-eastern coast of South America. For the mid-Atlantic barrier, the ability of species to live in floating debris such as logs, seaweeds and even human disposals great improve chance to cross the Atlantic Ocean. For the Amazon-Orinoco plume, species that are also associated to other habitats than reefs, such as sand and sponge bottoms, could live within the plume and cross it through a stepping-stone effect. For both types of barrier, species body size is a further significant predictor, probably increasing the chance of a population becoming established in the new area.