Thursday, January 28, 2016

[Ornithology • 2016] Integrative Taxonomy of the Plain-backed Thrush (Zoothera mollissima) complex (Aves, Turdidae) reveals Cryptic Species, including A New Species, Zoothera salimalii, from the eastern Himalayas


Himalayan Forest Thrush | Zoothera salimalii
 Alström, Rasmussen, Zhao, Xu, Dalvi, Cai, Guan, Zhang, Kalyakin, Lei & Olsson, 2016
   
photo: C. Brelsford    DOI:  10.1186/s40657-016-0037-2

Abstract
Background
The Plain-backed Thrush Zoothera mollissima breeds in the Himalayas and mountains of central China. It was long considered conspecific with the Long-tailed Thrush Zoothera dixoni, until these were shown to be broadly sympatric.

Methods
We revise the Z. mollissimaZ. dixoni complex by integrating morphological, acoustic, genetic (two mitochondrial and two nuclear markers), ecological and distributional datasets.

Results
In earlier field observations, we noted two very different song types of “Plain-backed” Thrush segregated by breeding habitat and elevation. Further integrative analyses congruently identify three groups: an alpine breeder in the Himalayas and Sichuan, China (“Alpine Thrush”); a forest breeder in the eastern Himalayas and northwest Yunnan (at least), China (“Himalayan Forest Thrush”); and a forest breeder in central Sichuan (“Sichuan Forest Thrush”). Alpine and Himalayan Forest Thrushes are broadly sympatric, but segregated by habitat and altitude, and the same is probably true also for Alpine and Sichuan Forest Thrushes. These three groups differ markedly in morphology and songs. In addition, DNA sequence data from three non-breeding specimens from Yunnan indicate that yet another lineage exists (“Yunnan Thrush”). However, we find no consistent morphological differences from Alpine Thrush, and its breeding range is unknown. Molecular phylogenetic analyses suggest that all four groups diverged at least a few million years ago, and identify Alpine Thrush and the putative “Yunnan Thrush” as sisters, and the two forest taxa as sisters. Cytochrome b divergences among the four Z. mollissima sensu lato (s.l.) clades are similar to those between any of them and Z. dixoni, and exceed that between the two congeneric outgroup species. We lectotypify the name Oreocincla rostrata Hodgson, 1845 with the Z. mollissima sensu stricto (s.s.) specimen long considered its type. No available name unambiguously pertains to the Himalayan Forest Thrush.

Conclusions
The Plain-backed Thrush Z. mollissima s.l. comprises at least three species: Alpine Thrush Z. mollissima s.s., with a widespread alpine breeding distribution; Sichuan Forest Thrush Z. griseiceps, breeding in central Sichuan forests; and Himalayan Forest Thrush, breeding in the eastern Himalayas and northwest Yunnan (at least), which is described herein as a new species. “Yunnan Thrush” requires further study.

Keywords: Systematics, Morphology, Bioacoustics, Altitudinal distributions, Genetic distances, Undescribed taxa, Zoothera dixoni, Lectotypification, Holotype


Fig. 5 Alpine Thrush Zoothera mollissima sensu stricto, Niubei Shan, Sichuan, China, mid June (Chao Zhao; same individual as in Figs. 6, 9, IOZ 20890 and probably also AV19499) (a, e, i, l); Himalayan Forest Thrush Z. salimalii, sp. nov., Dulongjiang, Yunnan, China, mid June (Per Alström; same individual as in Fig. 10, IOZ 19659 and AV19235) (b, f, j, m); Dulongjiang, Yunnan, China, mid June (Per Alström; same individual as in Fig. 10, IOZ 19658 and AV19240) (d, g); Sichuan Forest Thrush Z. griseiceps, Jiuding Shan, Sichuan, China, mid May (Per Alström; same individual as in Fig. 12, IOZ 20222 and AV19505) (c, h, k); Vietnam, 24 December 1929, holotype in BMNH (Per Alström) (n)

Himalayan Forest Thrush Zoothera salimalii, sp. nov.,  Dulongjiang, Yunnan, mid June 
photo: C. Brelsford    DOI:  10.1186/s40657-016-0037-2


Etymology: We name this new species for Dr Sálim Ali, in honor of his huge contributions to the development of Indian ornithology and conservation.

Status and conservation of all taxa: As the Alpine Thrush is widely distributed and its habitat is not under threat, it should be considered as being of least concern. Zoothera salimalii is locally common in West Bengal and Arunachal Pradesh, India, and locally abundant at Dulongjiang, Yunnan province, China. Because it is widely distributed and its habitat is not under any imminent threat (other than forest areas in general), it should be considered as being of least concern. Zoothera griseiceps is only known to breed in a rather small area in Sichuan province, China. However, as it is locally fairly common, and occurs in several protected areas, it is probably not under any imminent threat, at least not on its breeding grounds.


Fig. 7 Himalayan Forest Thrush Zoothera salimalii, sp. nov., Darjeeling District, West Bengal, India (Subrato Sanyal) (a); Baihualing, Yunnan, China, early February (Craig Brelsford; same individual as in Fig. 4, but other side of head; the tail has apparently been accidentally lost and is growing) (b); Darjeeling District, West Bengal, India (Subrato Sanyal; different individual from a) (c); Dulongjiang, Yunnan, mid June (Craig Brelsford; same individual) (d–f)

Conclusion: 
Based on analyses of plumage, morphometrics, mitochondrial and nuclear DNA, song, breeding habitat and geographical distributions, we conclude that Zoothera mollissima s.l. should be split into at least three species, one of which is described here as a new species: Alpine Thrush Z. mollissima s.s., Himalayan Thrush Zoothera salimalii (sp. nov.) and Sichuan Forest Thrush Z. griseiceps, all monotypic. In addition, a distinct lineage, “Yunnan Thrush”, was identified genetically, but as we have no corroborating evidence that it is distinct from Alpine Thrush, we refrain from describing it here. Z. dixoni should be retained as a distinct species.



Per Alström, Pamela C. Rasmussen, Chao Zhao, Jingzi Xu, Shashank Dalvi, Tianlong Cai, Yuyan Guan, Ruiying Zhang, Mikhail V. Kalyakin, Fumin Lei and Urban Olsson. 2016. Integrative Taxonomy of the Plain-backed Thrush (Zoothera mollissima) complex (Aves, Turdidae) reveals Cryptic Species, including A New Species.
Avian Research. 20167:1. DOI:  10.1186/s40657-016-0037-2  

New species of bird discovered in India, China by international team of scientists
Bird has been named the Himalayan Forest Thrush
: A new species of bird has been described in north-eastern India and adjacent parts of China by a team of scientists. The bird has been named the Himalayan Forest Thrush, Zoothera salimalii.

Himalayan Forest Thrush: New Species of Bird Discovered http://saevus.in/blog/himalayan-forest-thrush-new-species-discovered/ via @SaevusWildlife

Himalayan Forest Thrush — New Bird Species discovered in India and China http://www.conservationindia.org/articles/himalayan-forest-thrush
New species of bird discovered in India and China
http://phy.so/372515252 via @physorg_com

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