Fig. 1

Contemporary distribution and sampling map for N. australis and N. obscura. Nannoperca australis sampling sites are indicated in red, and N. obscura sites in blue. The distribution of N. australis is indicated with light green shading and dashed borders, with the distribution of N. obscura (also the region of co-occurrence) in darker green. The solid black line indicates the boundary of major drainage basins, and the dotted line demonstrates the approximate shoreline during glacial maxima. Bottom left inset depicts study region and major drainage basins in Australia. Top right inset depicts the full extent of species distributions