South America harbors 14 taxonomic orders of freshwater fishes with marine ancestry (e.g. stingrays, anchovies, herring, pufferfish), much more than found on any other continent. I am investigating the origins of marine derived fishes in South America by reconstructing biogeographic patterns and timing multiple independent marine derived lineages (see below for one example). This work has linked marine invaders to marine incursion events that penetrated deep into the South American continent. Ongoing research on this topic includes investigating the role of marine incursions in promoting diversification is select clades of freshwater fishes with marine ancestry.