Figure 2.

Phylogenetic tree structure and explicit phylogeographic mapping support the ‘pathway through the rainforest’ dispersal scenario. (a) Simplified consensus phylogenetic tree of 542 Bantu languages constructed from posterior sample of 500 trees. Triangle size is proportional to number of languages. Letters refer to Guthrie zones (figure 1). (b) Ancestral locations of numbered nodes in the tree and pathway of expansion are shown in relation to extant languages. (c) Distribution of inferred ancestral location of some nodes across PP trees shows uncertainty about precise locations but the overall pathway implied by these analyses remains the same. The dashed-line ellipse refers to the location of dispersal for languages leaving the rainforest as hypothesized by Rexova et al. [22] and the star represents the location of dispersal for East Bantu languages under the simplified rainforest-first dispersal scenario of de Filippo et al. [8]. These locations are not supported by the dispersal pathway inferred from our analyses.