SPECIES LIMITS IN THE “SCHISTOCICHLA”COMPLEX OF PERCNOSTOLA ANTBIRDS (PASSERIFORMES: THAMNOPHILIDAE)

Abstract The species-group in the genus Percnostola that is sometimes placed in the genus “Schistocichla” is shown to consist of seven, mostly allopatric, species. All seven are distinct morphologically; when their vocalizations were compared, 19 of 21 pairwise comparisons resulted in differences as great as or greater than those of syntopic species-pairs in this family. Differences in the two remaining comparisons were limited to two vocal characters, but one involved a pair whose ranges appear to abut without apparent physical barriers; members of the second pair were separated geographically by ∼2,400 km. Insights into speciation in the complex are relevant to conservation efforts and ultimately will be related to an ongoing genetic study to suggest a phylogeny and contribute to an understanding of avian evolution in Amazonia.