Patterns of avian diversification in Borneo: The case of the endemic Mountain Black-eye (Chlorocharis emiliae)

The Mountain Black-eye (Chlorocharis emiliae) is an endemic white-eye (Zosteropidae) of Borneo with a unique “sky island” distribution. We compared mitochondrial ND2, ND3, Cytb, and control region DNA sequences (2,194 nucleotides) to study the phylogeographic relationships of five populations of this species that span its range: Mounts Kinabalu, Trus Madi, Murud, Mulu, and Pueh. These comparisons showed that black-eyes are divided into two main clades that correspond generally to subspecific morphological groups: one in Sabah, Malaysia (Kinabalu and Trus Madi), and one in Sarawak, Malaysia (Murud, Mulu, and Pueh). The genetic and morphologic subdivision of black-eyes disputes the expected merging of populations during the Last Glacial Maximum (LGM), when montane forest presumably expanded and provided the opportunity for currently isolated populations to intermingle. Instead the genetic aging of black-eye populations indicates they diversified long before the LGM, and either did not expand sufficiently in range during the LGM to reach one another, or were reproductively isolated by the time of the LGM and thus prevented from interbreeding. Moreover, the subdivision between black-eyes in Sabah and Sarawak means that this species (and probably several other montane species) has a phylogeographic structure remarkably similar to Borneo's lowland bird populations, which are presumed to have evolved under different paleo-geographic conditions. The similar phylogeographic pattern found in both montane and lowland species requires that we rethink the causes of bird population diversification on the island of Borneo

Patterns of avian diversification in Borneo: The case of the endemic Mountain Black-eye (Chlorocharis emiliae)

The Mountain Black-eye (Chlorocharis emiliae) is an endemic white-eye (Zosteropidae) of Borneo with a unique ‘‘sky island’’ distribution. We compared mitochondrial ND2, ND3, Cytb, and control region DNA sequences (2,194 nucleotides) to study the phylogeographic relationships of five populations of this species that span its range: Mounts Kinabalu, Trus Madi, Murud, Mulu, and Pueh. These comparisons showed that black-eyes are divided into two main clades that correspond generally to subspecific morphological groups: one in Sabah, Malaysia (Kinabalu and Trus Madi), and one in Sarawak, Malaysia (Murud, Mulu, and Pueh). The genetic and morphologic subdivision of black-eyes disputes the expected merging of populations during the Last Glacial Maximum (LGM), when montane forest presumably expanded and provided the opportunity for currently isolated populations to intermingle. Instead the genetic aging of black-eye populations indicates they diversified long before the LGM, and either did not expand sufficiently in range during the LGM to reach one another, or were reproductively isolated by the time of the LGM and thus prevented from interbreeding. Moreover, the subdivision between black-eyes in Sabah and Sarawak means that this species (and probably several other montane species) has a phylogeographic structure remarkably similar to Borneo’s lowland bird populations, which are presumed to have evolved under different paleo-geographic conditions. The similar phylogeographic pattern found in both montane and lowland species requires that we rethink the causes of bird population diversification on the island of Borneo

Ornithological expeditions to Sarawak, Malaysian Borneo, 2007-2017

Louisiana State University, the University of Kansas, and the Universiti Malaysia Sarawak undertook collaborative research on the evolution and ecology of Bornean birds starting in 2005. This collaboration included a series of expeditions from 2007–2017 to collect and study birds at \u3e30 sites in Sarawak, Malaysian Borneo. Here we provide information on the study-sites and summarize the main discoveries resulting from the collaboration

Sundaland’s east–west rain forest population structure : variable manifestations in four polytypic bird species examined using RAD-Seq and plumage analyses

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