Figure 7.

Close‐up of clade Pygmarrhopalites A10 from Figure 6a illustrating timing information from estimates of molecular divergence and geological evidence supporting vicariance across the Mississippi River Valley: (a) 2.90–4.76 Ma (95% HDP) (blue bar) divergence time between Missouri and Illinois lineages (separated by gray dashed line), posterior probabilities at each node lower than 1 are not displayed; (b) late Pliocene/early Pleistocene timing (dashed arrow) of initial Mississippi River entrenchment (Cupples & Van Arsdale, 2014) and increased river discharge (Cox et al., 2014); (c) 3.25 ± 0.26 Ma (green column) timing of initial Green River karst incision and excavation (Granger et al., 2001); (d) 2.41 ± 0.14 Ma (orange column) timing of first glacial melt (Balco et al., 2005). Holocene (0.01 Ma to present) is not labeled