Figure 1.

Former and recent distribution of (A) Penelopides manillae and P. panini and of (B) Aceros waldeni and A. leucocephalus. The dashed lines approximately delineate the distribution ranges of the respective sister species. The illustration of the Philippines is restricted to larger islands and islands with former or recent occurrence of the studied hornbill species. Labeled islands are mentioned in the text. Sampled populations are indicated by island names in bold face.