Integrative taxonomy of the Russet Bush Warbler Locustella mandelli complex reveals a new species from central China

Abstract

Background: The Russet Bush Warbler Locustella (previously Bradypterus) mandelli complex occurs in mountains in the eastern Himalayas, southern China, Vietnam, the Philippines, and Indonesia. The taxonomy has been debated, with one (L. seebohmi) to four (L. seebohmi, L. mandelli, L. montis and L. timorensis) species having been recognised. Methods: We used an integrative approach, incorporating analyses of morphology, vocalizations and a molecular marker, to re-evaluate species limits in the L. mandelli complex. Results: We found that central Chinese L. mandelli differed from those from India through northern Southeast Asia to southeast China in plumage, morphometrics and song. All were easily classified by song, and (wing + culmen)/ tail ratio overlapped only marginally. Both groups were reciprocally monophyletic in a mitochondrial cytochrome b (cytb) gene tree, with a mean divergence of 1.0 ± 0.2%. They were sympatric and mostly altitudinally segregated in the breeding season in southern Sichuan province. We found that the Mt Victoria (western Myanmar) population differed vocally from other L. mandelli, but no specimens are available. Taiwan Bush Warbler L. alishanensis was sister to the L. mandelli complex, with the most divergent song. Plumage, vocal and cytb evidence supported the distinctness of the south Vietnamese L. mandelli idonea. The Timor Bush Warbler L. timorensis, Javan Bush Warbler L. montis and Benguet Bush Warbler L. seebohmi differed distinctly in plumage, but among-population song variation in L. montis exceeded the differences between some populations of these taxa, and mean pairwise cytb divergences were only 0.5-0.9%. We also found that some L. montis populations differed morphologically. Conclusions: We conclude that the central Chinese population of Russet Bush Warbler represents a new species, which we describe herein, breeding at mid elevations in Sichuan, Shaanxi, Hubei, Hunan and Guizhou provinces. The taxonomic status of the other allopatric populations is less clear. However, as they differ to a degree comparable with that of the sympatric L. mandelli and the new species, we elevate L. idonea to species status, and retain L. seebohmi and L. montis as separate species, the latter with timorensis as a subspecies. Further research should focus on different populations of L. montis and the Mt Victoria population of L. mandelli.

Analyses of phenotypic differentiations among South Georgian Diving Petrel (Pelecanoides georgicus) populations reveal an undescribed and highly endangered species from New Zealand

“…We refrained from using a colour chart, as this tool is not ideal when colours fade into each other [ 48 ]. In several taxonomic studies plumage characters are scored on larger scales (e.g., 1–10; [ 49 , 50 ]). We refrained from using such scales as they come with the arguable difficulty of distinguishing between neighbouring classes.…”

“…We tested for differences between pools within the PCA space with factorial ANOVAs, but excluded pools with small sample sizes ( n < 7). 2) We then applied univariate statistics to test for significant differences between pools using factorial ANOVAs followed by Tukey HSD tests for biometric characters (e.g., [ 48 ]) and Kruskal-Wallis rank sum tests followed by pair-wise comparisons with Welch’s two-sample t-tests for plumage characters (e.g., [ 49 , 50 ]). We excluded small sample sizes ( n < 7) from univariate statistics as well.…”

Taxonomic revision of the Sylvarum group of bumblebees using an integrative approach

“…Our PEPCK gene fragment contains gaps sites (representing an insertion or deletion and also called "indels") and our statistical method for phylogenetic estimation (ML and MB) consider the gap as missing data. Indeed, in most of taxonomic studies, the indels are treated as missing data as this is the case for birds (Alström et al, 2015;McKay et al, 2014), frogs (Glaw, Kohler, De la Riva, Vieites & Vences, 2010), mammals (Ndiaye et al, 2014), spiders (Rezac, Gasparo, Kral & Heneberg, 2014). Considered indels will increase the phylogenetic information even if they are located in introns (in our case, all indels are located in the first introns of the PEPCK gene fragment).…”

Pilot biodiversity assessment of the Hkakabo Razi passerine avifauna in northern Myanmar – implications for conservation from molecular genetics

“…The combined use of different independent analytical approaches for species diagnosis (using phenotypical and bioacoustic traits as well as molecular markers) including their taxonomy and systematic classification has recently been discussed under the flagship term 'integrative taxonomy' (Padial et al 2010, Schlick-Steiner et al 2010. This multi-dimensional approach has been applied to a number of South-East Asian and Indomalayan bird species (Irestedt et al 2013, Päckert et al 2014) some of them new to science (Alström et al 2015(Alström et al , 2016 including a re-evaluation of the species status of the endemic Rimator naungmungensis from northern Myanmar (Renner et al 2018).…”