Orthotomus tailorbirds (1 Viewer)

O. castaneiceps chloronotus of Luzon should be recognized as a separate species from O. castaneiceps castaneiceps due to its sister relationship with O. derbianus. It is highly divergent from both of these taxa and distinguishable from the gray-backed O. derbianus by having a greenish back. Collar (2011), who anticipated its species ranking, suggested the common name green-backed tailorbird. Orthotomus chloronotus Ogilvie-Grant, 1895, is the appropriate scientific name (Parkes, 1971; Watson et al., 1986).

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dnsallen said:

Should this be in the 'Philippine species limits' thread too?

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Richard Klim said:

Orthotomus (castaneiceps) chloronotus listed as a proposed split.
www.worldbirdnames.org/updates/proposed-splits

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Richard Klim said:

Lim, Chua, Benham, Oliveros, Rahman, Moyle & Sheldon 2014. Divergence history of the Rufous-tailed Tailorbird (Orthotomus sericeus) of Sundaland: Implications for the biogeography of Palawan and the taxonomy of island species in general. Auk 131(4): 629–642. [abstract]

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Taxonomy
... Our personal preference is not to change the classification of Rufous-tailed Tailorbird populations, i.e. maintain the subspecies as they are. Although the western Sunda and Borneo populations do not appear to us to differ from one another morphologically, fresh specimens from Sumatra and the Malay Peninsula might exhibit plumage differences from Bornean birds. Naming the Palawan population as a distinct taxon, e.g., in recognition of its genetic distinctiveness or in the case of new character discovery, will have to wait until genetic comparisons are made between it and the Cagayan Sulu population, because the Palawan population is subsumed under the name given the Cagayan Sulu population (Orthotomus sericeus nuntius) by Bangs (1922).

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Richard Klim said:

Lim, Chua, Benham, Oliveros, Rahman, Moyle & Sheldon 2014. Divergence history of the Rufous-tailed Tailorbird (Orthotomus sericeus) of Sundaland: Implications for the biogeography of Palawan and the taxonomy of island species in general. Auk 131(4): 629–642. [abstract]

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l_raty said:

Fuchs J, Zuccon D. 2018. On the genetic distinctiveness of tailorbirds (Cisticolidae: Orthotomus) from the South-east Asian mainland with the description of a new subspecies. Avian Res., 9: 31.
[whole paper]
[ZooBank register entry] (not public yet)

Abstract
Background: The Cambodian Tailorbird (Orthotomus chaktomuk) was one of the most recent major ornithological discoveries in South-east Asia as it originated from lowland seasonally flooded scrub within the densely inhabited floodplain around the Tonle Sap, Mekong and Bassac rivers (Cambodia). The Cambodian Tailorbird is sister to the Dark-necked Tailorbird (O. atrogularis) with very limited genetics and biometric differentiation. Between 2004 and 2012, evidences of a new population of Ashy Tailorbird (O. ruficeps) in SE Cambodia/Vietnam accumulated but no museum specimens were ever reported. The Ashy Tailorbird currently consists of eight subspecies among which the closest geographical populations, O. r. cineraceus (SE Burma to Malay Peninsula, Sumatra, Bangka and Belitung) and O. r. borneoensis (Borneo), are allopatric. Subspecific identification of the Cambodian Ashy Tailorbirds individuals was not possible because of the limited differences in plumage among subspecies.
Methods: We inspected the Orthotomus ruficeps specimens housed at the Museum National d’Histoire Naturelle (Paris) and discovered five specimens of O. ruficeps collected by Louis Rodolphe Germain in ‘Cochinchina’ (corresponding to southern Vietnam) during the nineteenth century. We sequenced one mitochondrial locus and gathered biometric data from these specimens and compared them with other Orthotomus lineages.
Results: The Ashy Tailord population from SE Cambodia and Vietnam is distinct from the two geographically close subspecies O. r. borneoensis (1.7%) and O. r. cineraceus (1.3%). O. chaktomuk is nested within O. atrogularis in the mitochondrial gene tree. The SE Cambodia/Vietnam population of O. ruficeps is distinct from the two other subspecies in bill shape.
Conclusion: Our study described the biometric and molecular distinctiveness of a recently re-discovered population of Ashy Tailord in SE Cambodia and Vietnam and suggests that this population constitutes an independent evolutionary lineage that we describe here as a new subspecies. The newly described Cambodian Tailorbird is nested within the Dark-necked Tailorbird and the genetic divergence is much lower than initially described (0.4‒0.7% vs 1.1‒1.4%).
Keywords: Orthotomus, Differentiation, Subspecies, Taxonomy

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