Integrative revision of species limits in the genus  Schiffornis (Aves: Tityridae) reveals cryptic diversity in the  Neotropics
Accurate species delimitation is essential for many biological subdisciplines.Nonetheless, taxonomic research has shown that current species diversity is underestimated,even in some of the best-studied groups of animals. Recent acoustic and genetic studies haveuncovered many morphologically cryptic bird species that were previously hidden bymorphology-based classifications. Yet, current estimates of bird species-level diversity in thetropics remain rooted in early morphological classifications, and so the need for integrativetaxonomic revision is urgent. Here, we take an integrative approach to examine species limitsin the genus Schiffornis, a widespread group of dull-plumaged, whistle-voiced suboscinepasserines of Neotropical humid-forest understory, currently considered to comprise sevenspecies. We measured geographic variation in song, morphology, and mitochondrial andgenome-wide nuclear markers to resolve the taxonomy of the genus. Our results suggest thatSchiffornis comprises 13 separately evolving population lineages, of which most qualify asspecies taxa under all species definitions. These include a cryptic new species, several speciessplits, and the resurrection of a taxon that was synonymized nearly a century ago in the S.turdina complex. We also found several hitherto unnoticed contact zones between diverginglineages and a leapfrog pattern of song variation in the S. turdina complex, and we highlightpotential avenues of further research of this genus