Estimation of ancestral ranges
BioGeoBEARS analyses identified DEC as the best model with restriction to dispersal and an influence of the closure of the Panama Isthmus and Andean Uplift (Ho7) as the hypothesis with strongest support (Figure 3, Table 5). The tribe most likely originated in South America (node I in Figure 3, Figure S6). The genus Archaeoprepona retained its ancestor’s range of origin (node II in Figure 3); other ranges with high probability also suggest a continental America origin (Figure S6). Similarly, Mesoprepona+Prepona likely originated in South America (node III; Figure 3); the other probable regions of origin comprise broad ranges as for its sister genus (Figure S6). The origin ofPrepona was most likely in mainland South America, excluding high elevation habitats of the western Andes (node IV; Figure 3). Finally, the clade that corresponds to the transition of color patterns from mostly blue to red Prepona species was found to have most likely originated in the Amazon and Eastern Andes (node V; Figure 3, Figure S6); the other ranges with high probability are narrow, where Andes, Amazon or Chocó are also likely regions of origin (Figure S6).
Discussion
In our study we hypothesized that shifts in color patterns and/or biogeographical events have contributed to Preponini diversification. We also hypothesized that the tribe originated in the Amazon basin, given its high species richness in this region. Despite finding high rates of wing color evolution, mostly in the red Prepona clade (Figure 2; Node V in Figure 3), we found that diversification rates in Preponini were not dependent on color evolution. However, major landscape reconfiguration, happening through most of the tribe’s evolutionary history, did seem to influence speciation rates and distribution patterns (Table 1 for models of biogeography dependent diversification analysis results). The Panama Isthmus and the uplift of the Andes mountain range together contributed most to the distribution patterns of extant Preponini. Cladogenesis happened mostly through dispersal to new ranges or splitting of broadly distributed taxa, as suggested by the Dispersal Extinction Cladogenesis model (DEC; Table 5), and Preponini likely originated within South America.