Molecular phylogenetics of Doraditos (Aves, Pseudocolopteryx ): Evolution of cryptic species, vocal and mechanical sounds

Abstract

While bird vocalizations (produced by the syrinx) have been the focus of countless studies, mechanical sounds (produced by external body structures) have received much less attention. In particular, the evolutionary interplay between these two modes of acoustic communication remains largely unstudied. Here, we present the first species-level molecular phylogeny of the doraditos (Pseudocolopteryx), reconstruct the evolutionary history of acoustic vocal and non-vocal characters, elucidate their relationship to feather modifications and aerial displays, and explore the influence of acoustics in the speciation of cryptic species. Our well-resolved phylogeny using four genes (ND2, COI, MB and ODC), recovered the monophyly of Pseudocolopteryx, resolving the relationships among its five species: ((((P. sclateri) P. acutipennis) P. dinelliana) P. citreola, P. flaviventris). Repetition and translocation of acoustic elements were commonplace in the evolution of Pseudocolopteryx. Songs were composed of introductory syllables and a final flourish. Bill-snapping sounds of P. sclateri were functionally homologous to introductory vocal syllables of the other species. The song of P. dinelliana evolved to high levels of complexity and repetition and is the syntactically most complex song in Pseudocolopteryx (and perhaps in the Tyrannidae). Aerial displays, mechanical wing sounds and modifications of primary feathers coevolved in three species: P. sclateri, P. acutipennis and P. dinelliana. Wing sounds documented for P. acutipennis and P. dinelliana differed markedly, and their production mechanisms might differ. The two cryptic and sibling species P. flaviventris and P. citreola diverged ∽60,000 Ya were not reciprocally monophyletic and are a case of extremely rapid evolutionary acoustic differentiation with morphological stasis.