Gila robusta species complex phylogenetics

The Gila robusta complex in the lower Colorado River includes three nominal and contested species (G. robusta, G. intermedia, and G. nigra) originally defined by morphological and meristic characters. In subsequent investigations, none of these characters proved diagnostic, and species assignments were made on the basis of population mean differences and capture location. Here we apply wide genomic coverage with range-wide sampling of fresh specimens to understand how differing taxonomic conclusions can be reconciled.