Andean tapaculos of the genus Scytalopus (Aves, Rhinocryptidae): a study of speciation using DNA sequence data.

Tapaculos of the genus Scytalopus are secretive birds which tunnel like mice through dense understory of humid forest in the Andes, Central America, and south-eastern Brazil. Their agoraphobic habits make Scytalopus species highly sensitive to habitat discontinuities, so they are well suited for analyzing diversification patterns in montane forest biota. This study uses DNA sequence data to test hypotheses about past speciation events. The DNA data support that allopatric and parapatric populations with different songs represent different species. The high degree of phylogenetic resolution obtained by DNA-data permits a better description of geographical patterns of endemism. The data suggests that the commonly observed biogeographic pattern, where related species have long linear distributions along the Andes in different altitudinal zones, arose by divergence in disjunct isolates rather than by parapatric divergence. The approach seems well suited for identifying areas that have a special role for the diversification process. The paper finally discusses how detailed phylogenetic studies can be used to test interpretations of biogeographic patterns of high relevance for pinpointing top priority areas for conservation.