| species delimitation and biogeography of the gnatcatchers and gnatwrens (aves: polioptilidae). | the new world avian family polioptilidae (gnatcatchers and gnatwrens) is distributed from argentina to canada and includes 15 species and more than 60 subspecies. no study to date has evaluated phylogenetic relationships within this family and the historical pattern of diversification within the group remains unknown. moreover, species limits, particularly in widespread taxa that show geographic variation, remain unclear. in this study, we delimited species and estimated phylogenetic relationshi ... | 2018 | 29551521 |