 |
| Plumage colour differences between taxa of the Schiffornis turdina complex and S. virescens. Individuals (A), (B), and (C) illustrate the range of plumage colour variation in turdina, olivacea, wallacii, cracrafti, intercedens, and amazonum. These taxa do not differ diagnostically from each other in plumage colour and together they encompass a wide range of variation, the extremes of which are illustrated herein... (D) represents steinbachi; (E) represents stenorhyncha; (F) represents veraepacis; (G) represents rosenbergi; (H) represents aenea; (I) represents virescens in Lima, Bocalini et Silveira, 2024. Illustrations by Eduardo Brettas. |
Abstract
Accurate species delimitation is essential for many biological subdisciplines. Nonetheless, current species diversity remains incompletely documented even in well-studied groups such as birds. Here, we take an integrative approach to examine species limits in the genus Schiffornis, a widespread group of dull-plumaged, whistle-voiced suboscine passerines of Neotropical humid-forest understory, currently considered to comprise seven species. We measured geographic variation in song, morphology, and mitochondrial and genome-wide nuclear markers to resolve the taxonomy of the genus. We show that Schiffornis comprises 13 separately evolving population lineages, of which most qualify as species taxa under all species definitions. These include a cryptic new species, several species splits, and the resurrection of a morphologically undifferentiated, but vocally and genetically distinct, taxon that was synonymized nearly a century ago in the Schiffornis turdina complex. We also found several hitherto unnoticed contact zones between diverging lineages and a leapfrog pattern of geographic song variation in the S. turdina complex, and we highlight potential avenues of further research of this genus.
Amazonia, Atlantic Forest, birds, leapfrog pattern of geographic variation, new species, sibling species, suboscine song, taxonomy
 |
| Plumage colour differences between taxa of the Schiffornis turdina complex and S. virescens. Individuals (A), (B), and (C) illustrate the range of plumage colour variation in turdina, olivacea, wallacii, cracrafti, intercedens, and amazonum. These taxa do not differ diagnostically from each other in plumage colour and together they encompass a wide range of variation, the extremes of which are illustrated herein (see Morphological variation and Supporting Information, Fig. S6 for more details). Individual (D) represents steinbachi. It differs from the previous taxa in having a more extensive rufous area on the breast, and a usually darker belly and undertail coverts. Individual (E) represents stenorhyncha, which differs from all other taxa of the S. turdina complex in having a rufous back and a strongly contrasted chest and belly. Individual (F) represents veraepacis. Its green is the most vibrant in the S. turdina complex. Individual (G) represents rosenbergi, which is more olivaceous, less yellowish, than veraepacis. Individual (H) represents aenea, the darkest species. Individual (I) represents virescens, which differs from all other congeners by its vibrant green plumage and more delicate bill. Illustrations by Eduardo Brettas. |
Rafael Dantas Lima, Fernanda Bocalini and Luís Fábio Silveira. 2024. Integrative Revision of Species Limits in the Genus Schiffornis (Aves: Tityridae) reveals Cryptic Diversity in the Neotropics. Zoological Journal of the Linnean Society. 200(4); 1048–1079. DOI: doi.org/10.1093/zoolinnean/zlad108 [28 September 2023]
