Seicercus

Abstract: The phylogeny of all species and nearly all subspecies of Seicercus and representatives of all subgenera in Phylloscopus was estimated based on two mitochondrial genes. According to the gene tree, and supported by non-molecular data, Seicercus belongs in three separate clades. Two of these include only taxa currently classified as Seicercus, while the third comprises S. xanthoschistos and P. occipitalis. These results suggest that both Seicercus and Phylloscopus are paraphyletic. The gene tree suggests two more cases of non-monophyly: (1) the ‘S. burkii complex’ is separated into two different clades, one of which also includes S. affinis and S. poliogenys; (2) two populations of S. affinis intermedius are more closely related to S. affinis ocularis than to a third population of intermedius. A recent proposal to split the ‘S. burkii complex’ into six species is corroborated, as is the recognition of the taxon cognitus as a colour morph of S. affinis intermedius. Our study also revealed unexpectedly large genetic divergences between three different populations of the monotypic S. poliogenys, indicating the presence of cryptic species. Our results underscore the importance of dense sampling at the specific and infraspecific levels in intrageneric phylogenetic studies.

Abstract: A new species of Phylloscopus warbler, which we name Phylloscopus calciatilis Limestone Leaf Warbler, is described from central and northern Vietnam and central and northern Laos; it probably also breeds in southernmost China. In morphology, the new species is very similar to Sulphur-breasted Warbler Phylloscopus ricketti, but it is smaller with a proportionately larger bill and rounder wing. Its song and calls are diagnostic. Based on mitochondrial and nuclear DNA, the new species is most closely related to P. ricketti and Yellow-vented Warbler Phylloscopus cantator, and it is inferred to be sister to the latter. The mitochondrial divergences between these three species are at the low end of the variation found in other species of Phylloscopus and Seicercus warblers, but greater than in other taxa generally treated as subspecies. Possible introgressive hybridization between the new species and P. ricketti is discussed, but more data are needed to establish whether it does occur and, if it does, to what extent. The new species appears to have a restricted breeding range in limestone karst environments, where it is locally common and therefore not under any immediate threat. In view of the recognition of the new species, all previous records of P. ricketti sensu lato need to be re-evaluated.

Abstract: Members of the passerine family Sylviidae are distributed widely around the Old World and the phylogenetic relationships of many species still remain controversial. In this study, we investigated the phylogeny and relationships among 37 species of 11 genera by analyzing DNA sequences obtained from the complete mitochondrial cytochrome b (cyt b) and partial cytochrome oxidase I (COI) genes. The data were analyzed by maximum-likelihood analysis and Bayesian inference. The results demonstrate that the current genus Phylloscopus is non-monophyletic, while Seicercus is synonymized with Phylloscopus or is a group within the genus Phylloscopus. We may conclude that within Phylloscopus there are close relations between P. magnirostris and P. borealis; among P. proregulus, P. yunnanensis, P. pulcher and P. maculipennis, as well as among P. occisinensis, P. schwarzi, P. armandii, P. collybita and P. fuscatus. Monophyly of the genus Cettia could not be corroborated; it is closely related to the genera Abroscopus and Tesia. However monophyly of Acrocephalus is supported. Furthermore, the close relationships between Sylvia and Zosterops and among Prinia, Orthotomus and Cisticola are also supported.