Fig. 1

Representation of two alternative dispersal hypotheses for the N. humilis/quaggulus complex investigated in this study. Solid black lines demark the rough geologic boundaries of major tectonic blocks as they correspond to present-day Central America. The dotted line marks the subdivision of the Chortis block into highland and lowland regions. The phylogenetic representation of the first dispersal hypothesis (H1) is indicated by the dotted lines; the alternative (H2) is shown with solid lines