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Hlavní autoři:	Berryman, Alex J., Collar, Nigel J.
Médium:	Recurso digital
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Vydáno:	Zenodo 2023
Témata:	Biodiversity Taxonomy Animalia Chordata Aves Passeriformes Pycnonotidae Rubigula Rubigula dispar Rubigula dispar matamerah
On-line přístup:	https://doi.org/10.5281/zenodo.20292052
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Rubigula dispar matamerah subsp. nov.Holotype.—Adult male, NHMUK 1888.4.1.724, collected at Sidjoendjoeng [Sijunjung], c. 00°42’S 100°58’E, c. 270 m, Sumatra, Indonesia, in October 1878 by Carl Bock. Bill 16.8 mm, wing 82 mm, tail 76 mm. The specimen label documents the iris colour as ‘red’.Diagnosis.—The iris of R. d. matamerah is basically red (varying individually between orange and crimson) instead of creamy yellow as in P. d. dispar. In both sexes the bill (mean males 16.9 vs. 15.7 mm, females 16.6 vs. 15.8 mm) and wing (males 81 vs. 78 mm, females 80 vs. 77 mm) are slightly longer than in the nominate.Description of holotype.—Head black except the throat, which has loose, pale fiery-red feather tubules. Upper breast orange-yellow tinged red, shading to mustard yellow on rest of underparts. Mantle, scapulars, back, rump and uppertail-coverts dull olive green. Wingcoverts and remiges dull blackish brown broadly fringed dull yellowish green. Uppertail blackish brown; undertail greyer with whitish shafts. Bill black. Legs blackish brown. Iris red, as noted on label. Illustrated in Fig. 2.Distribution.—Judged endemic to Sumatra, Indonesia, where photographs of red-eyed individuals were collated from the northernmost (Aceh) and southernmost (Lampung) provinces of the island. Like nominate R. d. dispar of Java and Bali, R. d. matamerah appears to be confined to elevations below c. 1,000 m.All photographs collated from West Java were obtained at Bogor Botanical Gardens, where the species is thought to have been introduced (see above). Consequently, these images cannot eliminate the possibility that native populations elsewhere in West Java belong to R. d. matamerah rather than the nominate. Such a distribution (where Sumatra and West Java share one taxon and the rest of Java holds its closest relative) would not be novel, and is observed in (e.g.) Chrysocolaptes flamebacks and White-rumped Shama Copsychus malabaricus, where Sumatran taxa occur on Java west of a line that runs approximately from Pelabuhanratu Bay to Cirebon (see Mees 1996). However, the only other evidence available to us from west of this line is provided by Nicholson (1881), who reported an adult female Ruby-throated Bulbul from Mt. Karang, Banten, in westernmost Java, with straw-yellow eyes. Consequently, we conclude with reasonable certainty that matamerah occurs only on Sumatra.Etymology. —‘Mata merah’ means ‘red eye’ in Bahasa Indonesia. We use the name as a noun in apposition.Conservation. —Owing to suspected declines caused by the songbird trade R. dispar has been listed as Vulnerable on the IUCN Red List (BirdLife International 2022) since its acceptance as a species by BirdLife International in 2016 (del Hoyo & Collar 2016). However, Symes et al. (2018) postulated that trapping pressure was causing the species to decline so rapidly it merited listing as Critically Endangered, the highest IUCN category of threat. By contrast, recent studies and records have suggested that the species is not commonly kept in captivity (Marshall et al. 2020) and remains frequently observed and widespread in the wild (Squires et al. 2021, eBird 2022). As a consequence, in 2022 the species was moved from the IUCN Asian Songbird Trade Specialist Group ‘Tier 1’ priority list (species considered most threatened by trade for which captive breeding is considered a major management intervention; see Collar & Wirth 2022) to the ‘Tier 2’ watch list (species for which population monitoring and research are recommended) (Chng & Shukhova 2022).Such monitoring will determine whether a re-evaluation of the species on the IUCN Red List is appropriate, but for the present it is likely to remain Vulnerable (AJB). A particularly valuable dimension to the monitoring of birds in markets will be to use iris colour to track the degree of movement of birds from Sumatra to Java (and presumably but much less probably vice versa). Which of the two subspecies is contributing more to the captive populations in Indonesia will be useful to gauge. We certainly recommend that the two taxa are treated as independent conservation units and suggest that—with iris colour providing a simple and reliable means of determination—those in captive-breeding programmes (such as the small one at Prigen Ark: J. K. Menner in litt. 2023) are maintained as separate populations, while those seized as part of the songbird trade are released—if that is the decision of the authorities—onto the correct island to prevent admixture.

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