Figure 7. A possible scenario for YHA lineage evolution and their colonization of Central and South America.

The most ancestral lineage is most likely NSA, whose distribution is restricted to the northernmost and north-west regions of South America. Their descendants colonized Central America through the Isthmus of Panama as well as southward regions of South America, giving rise to CA and SA lineages, respectively. The lineages diversified further into many taxa. However, more intense migrations and introgression likely did not lead to geographic differentiation of genetic markers in the SA lineage, in contrast to the CA lineage, which was subject to greater diversification by geographic locality.