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Aim: A current model of rain forest population diversification in Sundaland specifieseast–west vicariance into refugia during the early Pleistocene. In some taxa, thisdivision was followed by dispersal and apparent secondary contact on Borneo in thelate Pleistocene. To investigate genetic, morphological, spatial and temporal charac-teristics of the model, we compared genomic population and plumage variationamong four bird species with east–west mtDNA and plumage structure. Location: Borneo and western Sundaland (Sumatra and the Malay Peninsula).Methods: We quantified plumage patterns among populations of two muscicapids(Copsychus saularis and Kittacincla malabarica) and two timaliids (Mixornis gularis andTrichastoma malaccense), and compared them with population genetic patternsdetermined from (1) SNPs produced by RAD-Seq and (2) previously sequencedmtDNA. Results: All four species exhibit east–west variation in morphological and somegenetic characters, but patterns are idiosyncratic. Copsychus saularis’ mtDNA andplumage change gradually across Borneo, but RAD-Seq comparisons indicate nopopulation structure. In K. malabarica, all three characteristics change abruptly andconcurrently on Borneo. In M. gularis, the main east–west break occurs betweenBorneo and western Sundaland, with marginal mtDNA, plumage and RAD-Seq struc-ture on Borneo. T. malaccense exhibits two distinct mtDNA and genomic transitions,an early Pleistocene break between western Sundaland and Borneo, and a Pliocenebreak between the north-east and the rest of Borneo. Despite this deep geneticdivision, its plumage changes clinally across Borneo.Main conclusions: MtDNA, plumage and RAD-Seq patterns may vary depending onsuch factors as pre-Pleistocene distribution, habitat requirements and dispersalpropensity, differential introgression among the three character types, selection onplumage and phylogenetic relationships.

Aim The oriental magpie-robin (Copsychus saularis) of South and Southeast Asia is a phenotypically variable species that appears to be closely related to two endemic species of the western Indian Ocean: the Madagascar magpie-robin (Copsychus albospecularis) and the Seychelles magpie-robin (Copsychus sechellarum). This unusual distribution led us to examine evolutionary relationships in magpie-robins, and also the taxonomic significance of their plumage variation, via a molecular phylogenetic and population genetic analysis of C. saularis and C. albospecularis. Location Southern Asia from Nepal across Indochina to southern China, and the Indian Ocean from Madagascar to the Greater Sunda and Philippine islands. Methods We sequenced 1695 nucleotides of mitochondrial DNA comprising the complete second subunit of the nicotinamide adenine dinucleotide dehydrogenase (ND2) gene and 654 bases of the cytochrome c oxidase subunit I (COI) region in 51 individuals of eight C. saularis subspecies, 10 individuals of C. albospecularis (one subspecies) and single individuals of two other Copsychus species as outgroups. The data were analysed phylogenetically, with maximum likelihood, Bayesian, relaxed clock and parsimony methods, and geographically for patterns of genetic diversity. Results Phylogenetic analysis indicated that C. albospecularis lies within the nominal C. saularis, making C. saularis polyphyletic. Malagasy and non-Philippine Asian populations form a monophyletic group that is sister to a clade of Philippine populations. Within non-Philippine Asian populations, two groups are evident: black-bellied birds in the eastern Greater Sunda islands and white-bellied birds in the western Sundas and on mainland Asia. Main conclusions The phylogeny of magpie-robins suggests a novel pattern of dispersal and differentiation in the Old World. Ancestral magpie-robins appear to have spread widely among islands of the Indian Ocean in the Pliocene, probably aided by their affinity for coastal habitats. Populations subsequently became isolated in island groups, notably the Philippines, Madagascar and the Greater Sundas, leading to speciation in all three areas. Isolation in the Philippines may have been aided by competitive exclusion of C. saularis from Palawan by a congener, the white-vented shama (Copsychus niger). In the Greater Sundas, white-bellied populations appear to have invaded Borneo and Java recently, where they hybridize with resident black-bellied birds.

Aim Magpie-robins and shamas are forest and woodland birds of south Asia. There are two genera: Trichixos for the monotypic T. pyrrhopygus, and Copsychus for other species. Two species are widespread, whereas the others are restricted to specific islands. Endemicity is highest in the Philippines. Using phylogenetic methods, we examined how this group came to its unusual distribution. Location Mainland Asia from India to southern China, and islands from Madagascar to the Philippines. Particular emphasis is placed on the Greater Sundas and Philippines. Methods The phylogeny was estimated from DNA sequences of 14 ingroup taxa representing all nine currently recognized Copsychus and Trichixos species. The entire mitochondrial ND2 gene and portions of nuclear myoglobin intron 2 (Myo2) and transforming growth factor beta 2 intron 5 (TGFb2-5) were sequenced for all but two species. The phylogeny was reconstructed using maximum likelihood and Bayesian methods. The timing of divergence events was estimated using a relaxed molecular clock approach, and ancestral areas were examined using stochastic modelling. Results The group comprises three main clades corresponding to ecological types: Trichixos, a primary-forest specialist; Copsychus magpie-robins, openwoodland and coastal species; and Copsychus shamas, thick-forest species. Trichixos appears to be sister to the magpie-robins, rendering Copsychus polyphyletic. The dating of phylogenetic nodes was too ambiguous to provide substantial insight into specific geographical events responsible for divergence within the group. Some patterns are nevertheless clear. Copsychus shamas reached the Philippines, probably in two separate invasions, and split into endemic species. Copsychus malabaricus and C. saularis expanded widely in the Greater Sundas and mainland Southeast Asia without species-level diversification. Main conclusions Magpie-robins are excellent dispersers and have diversified into distinct species only on isolated oceanic islands. Trichixos, a poor disperser, is restricted to mature forests of the Malay Peninsula, Sumatra and Borneo. Copsychus shamas are intermediate in habitat preference and dispersal capabilities. Their endemism in the Philippines may be attributed to early colonization and specialization to interior forests. In the Greater Sundas, C. malabaricus and C. saularis populations split and came together on Borneo to form two separate subspecies (of each species), which now hybridize.