Reviewer's report Title:Integrative taxonomy of the Russet Bush Warbler Locustella mandelli complex reveals a new species from central China Version:1Date:27 January 2015 Reviewer number:2 Reviewer's report: Generally speaking, the paper “Integrative taxonomy of the Russet Bush Warbler Locustella mandelli complex reveals a new species from central China” told an interesting story about taxonomy. The study of the new species combined morphology, vocalizations and genetics and has some theoretical value which is worth publishing. However, while the mitochondrial DNA data support the results from morphology and vocalizations here, one gene is not enough to answer the question of genetics. Furthermore, some modifications may be necessary in order for this research to be publishable: - Major Compulsory Revisions: 1. It would be much better if the authors can make the paper more concise and clearly-structured, and make it easy to follow. - Minor Essential Revisions: L34 Abstract L37 Background Tell the name of the new species at beginning. Then introduce the background of the taxonomic status. L146 METHODS L 140-144 Put this section to the abstract “We conclude here, based on analyses of morphology, vocalizations, mitochondrial DNA, and our finding of local sympatry, that the central Chinese population of Russet Bush Warbler represents a separate species, which we describe as a new species. We also provide further evidence on the relationships and species limits within the L. mandelli complex. You should introduce the purpose of this paper instead of the conclusion. L 205 These should be shown in Table captions“( = p # 0.05; = p # 0.01; ** = p # 0.001)” L 291RESULTS The methods should not appear in the results section. L 346 Please explain what is meant by this, as it is unclear: “(Bill + wing) / tail ratios”, and introduce it in the Methods. L 618-624 “Distribution…….” is not a result, put it into introduction. L 626-661 Also “Habitat and elevation” is not a result, put it into introduction. L 663-678 I think you should combine these sections to discussion “Interaction between L. m. melanorhyncha and Sichuan Bush Warbler”. L 680 DISCUSSION L 680-813 The main conclusion should appear at beginning of this paragraph followed by a comparison of the Sichuan Bush Warbler to other species in morphology#song, and DNA. Finally, draw the conclusion that the Sichuan Bush Warbler should be classified as a separate species. The last paragraph should address any shortcomings or limitations in this study, and any problems or questions that should be investigated in the future. L 709-710 Put this sentence into the end of this paragraph. “The songs of Sichuan Bush Warbler and mandelli/melanorhyncha are easily separable by ear, with no intermediates ever heard.” Table 3 should be deleted as it provides the same information as the phylogenic tree in figure 14. It would be better if the authors can consider combining and deleting some figures. (only a suggestion) Level of interest:An article whose findings are important to those with closely related research interests Quality ofwritten English:Acceptable Statistical review:No, the manuscript does not need to be seen by a statistician.