Hypotheses of factors that could have shaped genetic and distribution patterns of fishes in the south-western CFR.

<p>Panel (a) assumes that populations could have been historically connected probably during a period of a major sea-level regression. Panel (b) describes the hypothesis that truncation of rivers during the Miocene-Pliocene major sea-level transgression fragmented populations and isolated them into upland areas that were not inundated (Refugia hypothesis), leading to allopatric divergence and the formation of unique lineages (indicated by the different colours). Panel (c) shows the river systems that would have coalesced forming the palaeoriver systems of the Last Glacial Maximum (LGM) (Palaeoriver hypothesis), allowing the exchange of unique lineages between systems sharing a common confluence. Panel (d) illustrates the hypothesis that alternative dispersal routes such as freshwater connections through low drainage divides could have facilitated range expansion of unique lineages (Interdrainage Dispersal hypothesis), leading to unique lineages being distributed across river systems that did not coalesce during the LGM.