Figure 4

Phenetic versus phylogenetic approach of species delimitation of two taxa of Acrochaete. A) Phenetic approach, i.e. pair wise comparison without consideration of the plesiomorphic status of the base pair 21/40 in the conserved region of Helix2 (H2) revealed that A. viridis and A. heteroclada differ by only one hCBC (A-U vs. G-U, respectively). In contrast, B) a phylogenetic approach taking the ancestral status (G-C) of the respective base pair into consideration resulted in the difference of one CBC (G-C → A-U) + one hCBC (G-C → G-U) between these two taxa. Whereas the phenetic approach would,- according to the CBC clade concept, regard A. viridis and A. heteroclada to belong to a single CBC clade (and potentially the same species), the phylogenetic approach showed A. viridis and A. heteroclada as two separate species. Base pair 21/40 as well as its plesiomorphic status (both in gray boxes) are mapped on the branches; and the evolving CBC/hCBC are indicated by blue dashed arrows.