Out of order warblers

Further light has been thrown onto the relationships between various members of the paraphlyetic warbler family Sylviidae by a new Chinese molecular study.

Using one partial and one complete mitochondrial DNA sequence from muscle tissue, the academic team analysed 33 Sylviid species collected in China and three from Slovakia, using Isabelline Shrike and Hair-crested Drongo as 'outgroups' to root their resulting trees. Japanese White-eye was also included, being suggested as hypothetically related to the genus Sylvia in several recent studies, as part of a babbler clade (a single branch or group containing all the descendants of a common ancestor).

While no complete genus was analysed, several relationships were either further confirmed or suggested. The genus Seicercus – containing Green-crowned S burkii and Chestnut-crowned S castaniceps Warblers – further confirmed as nested within a Phylloscopus clade, on branch containing Arctic <>P borealis, Greenish P trochiloides and Eastern Crowned P coronatus Warblers among others. The other branch of the generic dichotomy contained such well-known Western Palearctic species as Radde's Warbler P schwartzi and Common Chiffchaff P collybita, among others. Phylloscopus and Seicercus also have many anatomical features in common, including 12 tail feathers. The researchers stopped short of revising the genus, as they felt that not enough species had been included to come to any concrete taxonomic conclusions.

A close relationship between the white-eyes Zosterops and Sylvia warblers was also suggested despite their apparently superficial physical differences, though this was based on samples from only three species. The genus Cettia was shown to be a monophyletic group – that is, all members were each other's closest relatives to the exclusion of all the others in the analysis. A few Locustella and Prinia species were also included, and a close relationship was tentatively revealed between these and the genus Cisticola, nowadays often separated into its own family, the Cisticolidae. However, the latter grouping was statistically poorly supported in part, and will need further work.

Reference: Lei, X, Yin, Z, Lian, Z, Chen, C, Dai, C, Krištín, A, and Lei, F. 2010. Phylogenetic relationships of some Sylviidae species based on complete mtDNA cyt b and partial COI sequence data. Chinese Birds 1: 175-187.