This project provides a comprehensive and multidisciplinary approach to understand the molecular Systematics and Historical Biogeography of the 'Geophagus' brasiliensis complex. Combining RADseq, mtDNA, geometric morphometrics and geological data, we provide a series of broader and in-depth studies that significantly contribute to an improvement on the current knowledge about this group and the putative processes that originated their diversity. These data also contribute to a broader understanding of the events and patterns that may have influenced several other Neotropical fish groups.