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Pleistocene climatic oscillations exerted significant influences on the genetic structure and demography of rhesus macaque (Macaca mulatta) in eastern China. However, the evolutionary history of rhesus macaques in subtropical and temperate China remained unclear and/or controversial. Herein, we analyzed the autosomes, mitochondrial genomes, and Y‐chromosomes from 84 individuals of Chinese rhesus macaque. The results revealed that (1) all individuals were clustered into pan‐west and pan‐east genetic groups, which exhibited Shaanxi Province as the northernmost region of western dispersal route of rhesus macaques in China; (2) in subtropical and temperate China, rhesus macaques were divided into four lineages (TH, DB, HS, and QL), and their divergence times corresponded to the Penultimate Glaciation (300–130 kya) and Last Glaciation (70–10 kya), respectively; (3) the individuals from Mt. Taihangshan (TH) are closely related to individuals from Mt. Dabashan (DB) in the autosomal tree, rather than individuals from Mt. Huangshan (HS) as indicated by the mitogenome tree, which supports the hypothesis that the ancestral rhesus macaques radiated into Mt. Taihangshan from Mt. Huangshan via Mt. Dabashan; and (4) the demographic scenario of the four lineages showed the ancestral rhesus macaques bottleneck and expansion corresponding to the suitable habitat reduction and expansion, which confirmed they had experienced northward recolonization and southward retreat events from Mt. Huangshan area via Northern China Plain to Northernmost China along with Pleistocene glacial cycles. This study provides a new insight into understanding how Pleistocene glaciation has influenced faunal diversity in subtropical and temperate China, especially for those exhibiting differential patterns of sex dispersal. [ABSTRACT FROM AUTHOR]

Simple Summary: This study focuses on the assassin bug Sycanus bifidus, a widespread species in southern China, by analyzing its genetic data to trace how the Pleistocene's climate and geography influenced its distribution and evolution. There are two main genetic groups, which suggests that past climatic conditions and sea-level rises, especially concerning Hainan Island, profoundly impacted the spread and distribution of these bugs. This study's insights into the assassin bugs' historical population dynamics and adaptations to environmental changes emphasize the role of historical climatic fluctuations in shaping the distribution of species. The assassin bug Sycanus bifidus has a wide distribution across southern China. This study explored its distribution and evolution by analyzing mitochondrial and nuclear ribosomal RNA genes, revealing how Pleistocene climate and geological changes shaped its phylogeography. We identified two main clades, A and B, that diverged in the Middle Pleistocene. Hainan Island's populations form a unique group within Clade A, suggesting that the Qiongzhou Strait served as a dispersal corridor during glaciation. Rising sea levels likely separated the Hainan population afterward. Ecological niche modeling showed that both populations have been viable since the last interglacial period, with demographic analyses indicating possible expansions during the Middle and Late Pleistocene, driven by favorable climates. This study highlights the significant effects of Pleistocene sea-level and climatic changes on the distribution and evolution of S. bifidus in China. [ABSTRACT FROM AUTHOR]

Endemic species and their genetic diversity are critical components of global biodiversity, yet they usually face a higher risk of decline and extinction than species with broader distributions. Loss of genetic diversity within geographically restricted and fragmented ranges plays a significant role in driving endemic species to extinction, threatening their ability to adapt to environmental challenges. Hence, considering genetic diversity and its spatial distribution within populations is mandatory in planning conservation actions for narrow endemic species. Here, we investigated the population genetic diversity, structure and evolutionary history of the Calabrian black squirrel Sciurus meridionalis, a species endemic to the Calabrian region in the south of the Italian peninsula. A fine-scale sampling procedure was carried out throughout the whole species range, and genetic variation was assessed from multiple mitochondrial and nuclear markers. Phylogeographic and population structure analyses showed three evolutionary significant units within the current species range, each characterised by extremely low levels of genetic diversity. Bayesian phylogeographic analyses suggested that Calabrian black squirrel populations experienced a range fragmentation during the Last Glacial Maximum (∼20 ka), which geographically mirrors the three main mountain massifs within the species range. Historical demographic reconstructions revealed a recent and still ongoing demographic expansion for Calabrian black squirrel populations, likely promoted by a concurrent expansion of the Calabrian black pine in this area. Overall, our findings clarify the designation of the evolutionary significant units for a narrow endemic squirrel and underscore the importance of analysing range-wide population genetic data and considering species interactions when defining management strategies for narrow endemic species’ conservation.

Abstract Pleistocene climatic oscillations exerted significant influences on the genetic structure and demography of rhesus macaque (Macaca mulatta) in eastern China. However, the evolutionary history of rhesus macaques in subtropical and temperate China remained unclear and/or controversial. Herein, we analyzed the autosomes, mitochondrial genomes, and Y‐chromosomes from 84 individuals of Chinese rhesus macaque. The results revealed that (1) all individuals were clustered into pan‐west and pan‐east genetic groups, which exhibited Shaanxi Province as the northernmost region of western dispersal route of rhesus macaques in China; (2) in subtropical and temperate China, rhesus macaques were divided into four lineages (TH, DB, HS, and QL), and their divergence times corresponded to the Penultimate Glaciation (300–130 kya) and Last Glaciation (70–10 kya), respectively; (3) the individuals from Mt. Taihangshan (TH) are closely related to individuals from Mt. Dabashan (DB) in the autosomal tree, rather than individuals from Mt. Huangshan (HS) as indicated by the mitogenome tree, which supports the hypothesis that the ancestral rhesus macaques radiated into Mt. Taihangshan from Mt. Huangshan via Mt. Dabashan; and (4) the demographic scenario of the four lineages showed the ancestral rhesus macaques bottleneck and expansion corresponding to the suitable habitat reduction and expansion, which confirmed they had experienced northward recolonization and southward retreat events from Mt. Huangshan area via Northern China Plain to Northernmost China along with Pleistocene glacial cycles. This study provides a new insight into understanding how Pleistocene glaciation has influenced faunal diversity in subtropical and temperate China, especially for those exhibiting differential patterns of sex dispersal.

Intraspecific genetic diversity is a key aspect of biodiversity. Quaternary climatic change and glaciation influenced intraspecific genetic diversity by promoting range shifts and population size change. However, the extent to which glaciation affected genetic diversity on a global scale is not well established. Here we quantify nucleotide diversity, a common metric of intraspecific genetic diversity, in more than 38,000 plant and animal species using georeferenced DNA sequences from millions of samples. Results demonstrate that tropical species contain significantly more intraspecific genetic diversity than nontropical species. To explore potential evolutionary processes that may have contributed to this pattern, we calculated summary statistics that measure population demographic change and detected significant correlations between these statistics and latitude. We find that nontropical species are more likely to deviate from neutral expectations, indicating that they have historically experienced dramatic fluctuations in population size likely associated with Pleistocene glacial cycles. By analyzing the most comprehensive data set to date, our results imply that Quaternary climate perturbations may be more important as a process driving the latitudinal gradient in species richness than previously appreciated. [ABSTRACT FROM AUTHOR]

The assassin bug Sycanus bifidus has a wide distribution across southern China. This study explored its distribution and evolution by analyzing mitochondrial and nuclear ribosomal RNA genes, revealing how Pleistocene climate and geological changes shaped its phylogeography. We identified two main clades, A and B, that diverged in the Middle Pleistocene. Hainan Island’s populations form a unique group within Clade A, suggesting that the Qiongzhou Strait served as a dispersal corridor during glaciation. Rising sea levels likely separated the Hainan population afterward. Ecological niche modeling showed that both populations have been viable since the last interglacial period, with demographic analyses indicating possible expansions during the Middle and Late Pleistocene, driven by favorable climates. This study highlights the significant effects of Pleistocene sea-level and climatic changes on the distribution and evolution of S. bifidus in China.

The Quaternary glaciations had great impacts on the historical biogeography of small mammal species. Recent studies have showed the effects of these climatic cycles on the diversification of several Neotropical rodents, but these have focused on species whose distributions do not encompass the tropical Andes. Thus, the influences of these climatic dynamics on the evolutionary history of tropical Andean rodent species remain unknown. The effects of these climatic changes were addressed on Aepeomys lugens and A. reigi, two Thomasomyine endemics from the Cordillera de Mérida in the Venezuelan Andes. The past potential geographic distribution of both species was inferred using an ecological niche modeling approach. The estimations obtained indicated that the availability of the suitable climatic conditions for these taxa has varied in size and location during the last 140,000 years. The spatial projection of the niche models onto the climatic scenarios explored indicates that the effects over the historical distributions were smaller in A. lugens than in A. reigi. These results show that the current geographic distribution of both Andean rodents conceals complex biogeographic histories, and characterizations of the demographic history and genetic diversity will be required to understand the evolution of the genus Aepeomys in the Andes. [ABSTRACT FROM AUTHOR]

Insect speciation is among the most fascinating topics in evolutionary biology; however, its underlying mechanisms remain unclear. Allopatric speciation represents one of the major types of speciation and is believed to have frequently occurred during glaciation periods, when climatic oscillation may have caused suitable habitats to be fragmented repeatedly, creating geographical isolation among populations. However, supporting evidence for allopatric speciation of insects in East Asia during the Pleistocene glaciation remains lacking. We aim to investigate the effect of climatic oscillation during the Pleistocene glaciation on the diversification pattern and evolutionary history of hemipteran insects and to test the hypothesis of Pleistocene species stability using spinous assassin bugs Sclomina (Hemiptera: Reduviidae), a small genus widely distributed in southern China but was later found to have cryptic species diversity. Here, using the whole mitochondrial genome (mitogenome) and nuclear ribosomal RNA genes, we investigated both interspecific and intraspecific diversification patterns of spinous assassin bugs. Approximate Bayesian computation, ecological niche modeling, and demographic history analyses were also applied to understand the diversification process and driven factors. Our data suggest that the five species of Sclomina are highly diverged, despite three of them currently being cryptic. Speciation occurred during the Pleistocene when suitable distribution areas were possibly fragmented. Six phylogeographic groups in the type species S. erinacea were identified, among which two groups underwent expansion during the early Last Glacial Period and after Last Glacier Maximum. Our analyses suggest that this genus may have experienced climate‐driven habitat fragmentation and postglacial expansion in the Pleistocene, promoting allopatric speciation and intraspecific diversification. Our results reveal underestimated species diversity in a small insect group and illustrate a remarkable example of allopatric speciation of insects in East Asia promoted by Pleistocene climatic oscillations. These findings provide important insights into the speciation processes and aid the conservation of insect species diversity. [ABSTRACT FROM AUTHOR]

Regional phylogeographic studies have long been conducted in the southeastern United States for a variety of species. With some exceptions, many of these studies focus on single species or single clades of organisms, and those considering multiple species tend to focus on deep historical breaks causing differentiation. However, in many species more recent factors may be influencing genetic diversity. To understand the roles of historic and contemporary processes in structuring genetic diversity, we reanalyzed existing genetic data from Southeast of North America using approaches gleaned from phylogeographic and landscape genetic literature that were implemented across species including AMOVAs, PCoAs, Species Distribution Modelling, and tests of isolation by distance, environment, and habitat instability. Genetic variance was significantly partitioned by ecoregions, watersheds, and across phylogeographic breaks in the majority of species. Similarly, genetic variation was significantly associated with some combination of geographic or environmental distance or habitat instability in most species. Patterns of genetic variation were largely idiosyncratic across species. While habitat instability over time is significantly correlated with genetic diversity in some species, it appears generally less important than isolation by geographic or environmental distance. Our results suggest that many factors, both historical and contemporary, impact genetic diversity within a species, and more so, that these patterns aren’t always similar in closely related species. This supports the importance of species- specific factors and cautions against assumptions that closely related species will respond to historical and contemporary forces in similar ways.

The abundant centre model (ACM) predicts that the suitability of environmental conditions for a species decreases from the centre of its distribution toward its range periphery and, consequently, its populations will become scarcer, smaller and more isolated, resulting in lower genetic diversity and increased differentiation. However, little is known about whether genetic diversity shows similar patterns along elevational and latitudinal gradients with similar changes in important environmental conditions. Using microsatellite markers, we studied the genetic diversity and structure of 20 populations each of Anthyllis vulneraria along elevational gradients in the Alps from the valleys to the elevational limit (2500 m) and along a latitudinal gradient (2500 km) from Central Europe to the range margin in northern Scandinavia. Both types of gradients corresponded to an 11.5°C difference in mean annual temperature. Genetic diversity strongly declined and differentiation increased with latitude in line with the predictions of the ACM. However, as population size did not decline with latitude and genetic diversity was not related to population size in A. vulneraria, this pattern is not likely to be due to less favorable conditions in the North, but due to serial founder effects during the post‐glacial recolonization process. Genetic diversity was not related to elevation, but we found significant isolation by distance along both gradients, although the elevational gradient was shorter by orders of magnitude. Subarctic populations differed genetically from alpine populations indicating that the northern populations did not originate from high elevational Alpine ones. Our results support the notion that postglacial latitudinal colonization over large distances resulted in a larger loss of genetic diversity than elevational range shifts. The lack of genetic diversity in subarctic populations may threaten their long‐term persistence in the face of climate change, whereas alpine populations could benefit from gene flow from low‐elevation populations. [ABSTRACT FROM AUTHOR]

Unraveling the phylogeographic histories of species remains a key endeavor for comprehending the evolutionary processes contributing to the rich biodiversity and high endemism found in East Asia. In this study, we explored the phylogeographic patterns and demographic histories of three endemic fishfly and dobsonfly species ( Neochauliodes formosanus , Protohermes costalis , and Neoneuromus orientalis ) belonging to the holometabolan order Megaloptera. These species, which share a broad and largely overlapping distribution, were analyzed using comprehensive mitogenomic data. Our findings revealed a consistent influence of vicariance on the population isolation of Neoc. formosanus and P. costalis between Hainan, Taiwan, and the East Asian mainland during the early Pleistocene, potentially hindering subsequent colonization of the later diverged Neon. orientalis to these islands. Additionally, we unveiled the dual function of the major mountain ranges in East Asia, serving both as barriers and conduits, in shaping the population structure of all three species. Notably, we demonstrated that these co-distributed species originated from Southwest, Southern, and eastern Central China, respectively, then subsequently migrated along multi-directional routes, leading to their sympatric distribution on the East Asian mainland. Furthermore, our results highlighted the significance of Pleistocene land bridges along the eastern coast of East Asia in facilitating the dispersal of mountain-dwelling insects with low dispersal ability. Overall, this study provides novel insight into the synergistic impact of Pleistocene geological and climatic events in shaping the diversity and distribution of aquatic insects in East Asia.

Abstract The abundant centre model (ACM) predicts that the suitability of environmental conditions for a species decreases from the centre of its distribution toward its range periphery and, consequently, its populations will become scarcer, smaller and more isolated, resulting in lower genetic diversity and increased differentiation. However, little is known about whether genetic diversity shows similar patterns along elevational and latitudinal gradients with similar changes in important environmental conditions. Using microsatellite markers, we studied the genetic diversity and structure of 20 populations each of Anthyllis vulneraria along elevational gradients in the Alps from the valleys to the elevational limit (2500 m) and along a latitudinal gradient (2500 km) from Central Europe to the range margin in northern Scandinavia. Both types of gradients corresponded to an 11.5°C difference in mean annual temperature. Genetic diversity strongly declined and differentiation increased with latitude in line with the predictions of the ACM. However, as population size did not decline with latitude and genetic diversity was not related to population size in A. vulneraria, this pattern is not likely to be due to less favorable conditions in the North, but due to serial founder effects during the post‐glacial recolonization process. Genetic diversity was not related to elevation, but we found significant isolation by distance along both gradients, although the elevational gradient was shorter by orders of magnitude. Subarctic populations differed genetically from alpine populations indicating that the northern populations did not originate from high elevational Alpine ones. Our results support the notion that postglacial latitudinal colonization over large distances resulted in a larger loss of genetic diversity than elevational range shifts. The lack of genetic diversity in subarctic populations may threaten their long‐term persistence in the face of climate change, whereas alpine populations could benefit from gene flow from low‐elevation populations.

In a landmark comparative phylogeographic study, "Comparative phylogeography of unglaciated eastern North America," Soltis et al. (Molecular Ecology, 2006, 15, 4261) identified geographic discontinuities in genetic variation shared across taxa occupying unglaciated eastern North America and proposed several common biogeographical discontinuities related to past climate fluctuations and geographic barriers. Since 2006, researchers have published many phylogeographical studies and achieved many advances in genotyping and analytical techniques; however, it is unknown how this work has changed our understanding of the factors shaping the phylogeography of eastern North American taxa. We analyzed 184 phylogeographical studies of eastern North American taxa published between 2007 and 2019 to evaluate: (1) the taxonomic focus of studies and whether a previously detected taxonomic bias towards studies focused on vertebrates has changed over time, (2) the extent to which studies have adopted genotyping technologies that improve the resolution of genetic groups (i.e., NGS DNA sequencing) and analytical approaches that facilitate hypothesis‐testing (i.e., divergence time estimation and niche modeling), and (3) whether new studies support the hypothesized biogeographic discontinuities proposed by Soltis et al. (Molecular Ecology, 2006, 15, 4261) or instead support new, previously undetected discontinuities. We observed little change in taxonomic focus over time, with studies still biased toward vertebrates. Although many technological and analytical advances became available during the period, uptake was slow and they were employed in only a small proportion of studies. We found variable support for previously identified discontinuities and identified one new recurrent discontinuity. However, the limited resolution and taxonomic breadth of many studies hindered our ability to clarify the most important climatological or geographical factors affecting taxa in the region. Broadening the taxonomic focus to include more non‐vertebrate taxa, employing technologies that improve genetic resolution, and using analytical approaches that improve hypothesis testing are necessary to strengthen our inference of the forces shaping the phylogeography of eastern North America. [ABSTRACT FROM AUTHOR]

Bryophytes generally have broad geographical ranges that suggest high dispersal ability. The aim of this study was to test hypotheses about dispersal limitation, as indicated by isolation by distance, in four spore-producing species of the moss genus Sphagnum (Sphagnum carolinianum , Sphagnum missouricum , Sphagnum macrophyllum and Sphagnum pylaesii) and to assess whether plants in the southern USA harbour high levels of unique alleles and/or other indicators of exceptional genetic diversity. Isolation by distance was detected in all four species, but regional patterns of genetic structure were very species specific. Northern and southern genotype groups were detected in S. carolinianum and S. missouricum , but in S. pylaesii plants from the Adirondack Mountains of New York were genetically distinct from others to the north and south. One species, S. macrophyllum , exhibited differentiation between northern and southern genetic groups that appeared to reflect more ancient phylogenetic diversification. [ABSTRACT FROM AUTHOR]

Abstract In a landmark comparative phylogeographic study, “Comparative phylogeography of unglaciated eastern North America,” Soltis et al. (Molecular Ecology, 2006, 15, 4261) identified geographic discontinuities in genetic variation shared across taxa occupying unglaciated eastern North America and proposed several common biogeographical discontinuities related to past climate fluctuations and geographic barriers. Since 2006, researchers have published many phylogeographical studies and achieved many advances in genotyping and analytical techniques; however, it is unknown how this work has changed our understanding of the factors shaping the phylogeography of eastern North American taxa. We analyzed 184 phylogeographical studies of eastern North American taxa published between 2007 and 2019 to evaluate: (1) the taxonomic focus of studies and whether a previously detected taxonomic bias towards studies focused on vertebrates has changed over time, (2) the extent to which studies have adopted genotyping technologies that improve the resolution of genetic groups (i.e., NGS DNA sequencing) and analytical approaches that facilitate hypothesis‐testing (i.e., divergence time estimation and niche modeling), and (3) whether new studies support the hypothesized biogeographic discontinuities proposed by Soltis et al. (Molecular Ecology, 2006, 15, 4261) or instead support new, previously undetected discontinuities. We observed little change in taxonomic focus over time, with studies still biased toward vertebrates. Although many technological and analytical advances became available during the period, uptake was slow and they were employed in only a small proportion of studies. We found variable support for previously identified discontinuities and identified one new recurrent discontinuity. However, the limited resolution and taxonomic breadth of many studies hindered our ability to clarify the most important climatological or geographical factors affecting taxa in the region. Broadening the taxonomic focus to include more non‐vertebrate taxa, employing technologies that improve genetic resolution, and using analytical approaches that improve hypothesis testing are necessary to strengthen our inference of the forces shaping the phylogeography of eastern North America.

The relative importance of gene flow, genetic drift, and natural selection in driving genetic divergence of local populations, as well as the factors that disrupt gene flow in natural populations, are uncertain. Comparative analyses enable us to test explicit hypotheses regarding the roles of these factors. Gannets (Morus spp.) include three morphologically and ecologically similar seabird species: the Cape Gannet M. capensis, which breeds in southern Africa; the Australasian Gannet M. serrator, which breeds in southeastern Australia and New Zealand; and the Northern Gannet M. bassanus, which breeds in the North Atlantic. We assessed the extent of differentiation in mitochondrial control region sequences and morphometrics among colonies of each species to test mechanisms of divergence. No evidence was found for introgression of mitochondrial DNA between Cape and Australasian gannets, despite the existence of mixed-species pairs, consistent with their taxonomic status as biological species. Significant population differentiation, both in control region sequences and in morphology, was found within both Australasian and Northern gannets. Analyses based on coalescent theory indicated that little to no female-mediated gene flow occurs either between Australasian Gannets in Australia versus New Zealand, or between Northern Gannets in Canada versus Europe. Divergence of these regional populations, as well as Cape versus Australasian gannets, appears to pre-date the Pleistocene glaciations and corresponds to differences in non-breeding distributions. Northern and Australasian gannets may each represent at least two management units for conservation, but additional data are needed on nuclear DNA variation in individuals sampled from more colonies to confirm this result. [ABSTRACT FROM AUTHOR]

Abstract Recurring glacial cycles through the Quaternary period drastically altered the size and distribution of natural populations of North American flora and fauna. The “southerly refugia model” has been the longstanding framework for testing the effects of glaciation on contemporary genetic patterns; however, insights from ancient DNA have contributed to the reconstruction of more complex histories for some species. The American badger, Taxidea taxus, provides an interesting species for exploring the genetic legacy of glacial history, having been hypothesized to have postglacially emerged from a single, southerly refugium to recolonize northern latitudes. However, previous studies have lacked genetic sampling from areas where distinct glacial refugia have been hypothesized, including the Pacific Northwest and American Far North (Yukon, Alaska). In order to further investigate the phylogeographic history of American badgers, we collected mitochondrial DNA sequence data from ancient subfossil material collected within the historical range (Alaska, Yukon) and combined them with new and previously published data from across the species' contemporary distribution (n = 1,207). We reconstructed a mostly unresolved phylogenetic tree and star‐like haplotype network indicative of emergence from a largely panmictic glacial refugium and recent population expansion, the latter further punctuated by significantly negative Tajima's D and Fu's Fs values. Although directionality of migration cannot be unequivocally inferred, the moderate to high levels of genetic variation exhibited by American badgers, alongside the low frequency of haplotypes with indels in the Midwest, suggest a potential recolonization into central North America after the hypothesized ice‐free corridor reopened ~13,000 years ago. Overall, the expanded reconstruction of phylogeographic history of American badgers offers a broader understanding of contemporary range‐wide patterns and identifies unique genetic units that can likely be used to inform conservation of at‐risk populations at the northern periphery.

The Moračke Planine Mountains, situated in the central part of Montenegro, were the center of intensive Pleistocene glaciation. Specific type of moraines - hummocky ones, which have not been recorded in the southeastern Dinarides up to now, were recently identified and investigated in western part of the Moračke Planine Mts. Moraine material accumulated on limestone basement, where several tens of irregularly distributed hummocks and similar number of bowl-shaped dolines have been carved already. The hummocky moraines formed in the glaciokarst landscape where the well-developed karst morphology has been shaped before glaciation. Pre-glacial karst morphology determined the direction of glacier movement as well as its main morphological characteristics (thickness and width). During the most intensive glaciation phase (МIS 12) the Lukavičko-lukovski Glacier, spread out from the central part of mountain towards west, reaching a length of 16.5 km. Due to uneven glacier thickness, the deglaciation process led to its breaking and separation of the lower and shorter part from the rest of the icy mass. Stagnant state of the icy mass led to specific accumulation of moraine material in a form of numerous hummocks, whose melting produced a bowl-shaped dolinas in-between. The paleogeographic significance of hummocky moraines lies in the possibilities of more detailed studies of the Pleistocene glaciers specifics that arise from their evolution in glacio-karst conditions.

Aim: Freshwater mussels share habitat and are parasites of freshwater fishes during the larval life stage. Therefore, models of fish biogeography may also explain the historical biogeography of freshwater mussels. We tested this assumption using predictions of three biogeographic models constructed for northern Gulf of Mexico drainages on a freshwater mussel species complex. Specifically, we tested (1) if speciation was due to vicariant events of fluctuating sea levels that separated lineages east‐west of the Mobile Basin (Central Gulf Coast speciation hypothesis), (2) if the timing of divergences occurred 8.5–3.5 MYA (Gulf Coast allopatric speciation model) and (3) if diversification in Mississippi River populations was recent and for evidence of population increase consistent with range expansion into northern deglaciated regions (Pleistocene glaciation model). Location: Eastern North America. Taxon: Freshwater mussels (Bivalvia: Unionidae), Lampsilis teres and L. floridensis. Methods: We collected 249 specimens from 73 localities across the group's distribution. We used three molecular markers (COI, NDI & ITSI) to conduct time calibrated Bayesian phylogenetic analyses, phylogeographic analyses (AMOVA & SAMOVA) and demographic analyses including Bayesian skyline plots. Results: Lampsilis teres and L. floridensis are allopatric species whose distributions meet at the eastern edge of the Mobile Basin. Speciation was estimated to occur in the late Miocene. Populations from isolated river systems surrounding the Gulf of Mexico are almost all monophyletic. Mississippi drainage samples formed a shallow clade with recent diversification and showed evidence of recent population expansion. Main conclusions: The historical biogeography of the L. teres species complex is broadly consistent with tested ichthyofaunal models. The timing of speciation and intraspecific divergences correspond to low sea‐level events suggesting that Gulf Coast sea‐level fluctuations are responsible for dispersal (sea‐level recession) and subsequent cladogenesis (sea‐level inundation). Consistent with numerous other freshwater studies, we found the Mobile Basin to be a suture zone, which may be due to the narrow, offshore continental shelf. [ABSTRACT FROM AUTHOR]

Abstract Background Understanding the factors shaping population genetic structure is important for evolutionary considerations as well as for management and conservation. While studies have revealed the importance of palaeogeographic changes in shaping phylogeographic patterns in multiple marine fauna, the role of reproductive behaviour is rarely considered in reef fishes. We investigated the population genetics of three commercially important aggregating grouper species in the Indo-West Pacific, namely the camouflage grouper Epinephelus polyphekadion, the squaretail coral grouper Plectropomus areolatus, and the common coral trout P. leopardus, with similar life histories but distinct spatio-temporal characteristics in their patterns of forming spawning aggregations. Results By examining their mitochondrial control region and 9–11 microsatellite markers, we found an overarching influence of palaeogeographic events in the population structure of all species, with genetic breaks largely coinciding with major biogeographic barriers. The divergence time of major lineages in these species coincide with the Pleistocene glaciations. Higher connectivity is evident in E. polyphekadion and P. areolatus that assemble in larger numbers at fewer spawning aggregations and in distinctive offshore locations than in P. leopardus which has multiple small, shelf platform aggregations. Conclusions While palaeogeographic events played an important role in shaping the population structure of the target species, the disparity in population connectivity detected may be partly attributable to differences in their reproductive behaviour, highlighting the need for more investigations on this characteristic and the need to consider reproductive mode in studies of connectivity and population genetics.

Pleistocene climate cycles greatly influenced the distributions of kelps in northern seas and gated trans-Arctic dispersals between the North (N) Pacific and N Atlantic oceans. Here, we used partial sequences of the mitochondrial DNA cytochrome oxidase I-5′ (COI) and plastid ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit-3′ (rbcL) to resolve the phylogeography of the kelp Hedophyllum nigripes in the Gulf of Alaska and globally. In the Gulf of Alaska, genetic diversity was moderate (COI: h = 0.493 ± 0.076, n = 57; rbcL: h = 0.578 ± 0.00047, n = 54), but nucleotide diversity was small (COI: θπ = 0.00114 ± 0.00100, n = 57; rbcL: θπ = 0.0001 ± 0.00089, n = 54). Concatenated sequences showed strong haplotype-frequency differences among populations (ΦST = 0.728). The addition of previously published COI sequences from British Columbia showed a general absence of southern haplotypes in the Gulf of Alaska, supporting the conclusion of northern ice-age refugia. COI sequences in Canadian Arctic-Northwestern (NW) Atlantic populations differed by 1–2 mutation from Northeastern (NE) Pacific sequences, and unexpectedly, were marginally more closely related to populations in British Columbia than to geographically intermediate populations in the Gulf of Alaska. COI haplotypes from the Svalbard Archipelago in the NE Atlantic showed no variability and differed by 1–2 mutations from haplotypes in the NW Atlantic. Time-calibrated genetic divergences indicated trans-Arctic dispersal(s) from the N Pacific into the N Atlantic in the mid-Pleistocene. [ABSTRACT FROM AUTHOR]

We gathered mitochondrial DNA sequences (557 bp from the control region in 935 specimens and 668 bp of the cytochrome b gene in 139 specimens) of Pacific herring collected from 20 nearshore localities spanning the species' extensive range along the North Pacific coastlines of Asia and North America. Haplotype diversity and nucleotide diversity were high, and three major phylogeographic lineages (sequence divergences ca. 1.5%) were detected. Using a variety of phylogenetic methods, coalescent reasoning, and molecular dating interpreted in conjunction with paleoclimatic and physiographic evidence, we infer that the genetic make-up of extant populations of C. pallasii was shaped by Pleistocene environmental impacts on the historical demography of this species. A deep genealogical split that cleanly distinguishes populations in the western vs. eastern North Pacific probably originated as a vicariant separation associated with a glacial cycle that drove the species southward and isolated two ancestral populations in Asia and North America. Another deep genealogical split may have involved either a vicariant isolation of a third herring lineage (perhaps originally in the Gulf of California) or it may have resulted simply from the long coalescent times that are possible in large populations. Coalescent analyses showed that all the three evolutionary lineages of C. pallasii experienced major expansions in their most recent histories after having remained more stable in the preceding periods. Independent of the molecular calibration chosen, populations of C. pallasii appear to have remained stable or grown throughout the periods that covered at least two major glaciations, and probably more.

The Arctic is experiencing a rapid shift toward warmer regimes, calling for a need to understand levels of biodiversity and ecosystem responses to climate cycles. This study presents genetic data for 109 Arctic marine forest species (seaweeds), which revealed contiguous populations extending from the Bering Sea to the northwest Atlantic, with high levels of genetic diversity in the east Canadian Arctic. One-fifth of the species sampled appeared restricted to Arctic waters. Further supported by hindcasted species distributions during the Last Glacial Maximum, we hypothesize that Arctic coastal systems were recolonized from many geographically disparate refugia leading to enriched diversity levels in the east Canadian Arctic, with important contributions stemming from northerly refugia likely centered along southern Greenland. Our results suggest Arctic marine biomes persisted through cycles of glaciation, leading to unique assemblages in polar waters, rather than being entirely derived from southerly (temperate) areas following glaciation. As such, Arctic marine species are potentially born from selective pressures during Cenozoic global cooling and eventual ice conditions beginning in the Pleistocene. Arctic endemic diversity was likely additionally driven by repeated isolations into globally disparate refugia during glaciation. This study highlights the need to take stock of unique Arctic marine biodiversity. Amplification of warming and loss of perennial ice cover are set to dramatically alter available Arctic coastal habitat, with the potential loss of diversity and decline in ecosystem resilience. [ABSTRACT FROM AUTHOR]

Recurring glacial cycles through the Quaternary period drastically altered the size and distribution of natural populations of North American flora and fauna. The "southerly refugia model" has been the longstanding framework for testing the effects of glaciation on contemporary genetic patterns; however, insights from ancient DNA have contributed to the reconstruction of more complex histories for some species. The American badger, Taxidea taxus, provides an interesting species for exploring the genetic legacy of glacial history, having been hypothesized to have postglacially emerged from a single, southerly refugium to recolonize northern latitudes. However, previous studies have lacked genetic sampling from areas where distinct glacial refugia have been hypothesized, including the Pacific Northwest and American Far North (Yukon, Alaska). In order to further investigate the phylogeographic history of American badgers, we collected mitochondrial DNA sequence data from ancient subfossil material collected within the historical range (Alaska, Yukon) and combined them with new and previously published data from across the species' contemporary distribution (n = 1,207). We reconstructed a mostly unresolved phylogenetic tree and star‐like haplotype network indicative of emergence from a largely panmictic glacial refugium and recent population expansion, the latter further punctuated by significantly negative Tajima's D and Fu's Fs values. Although directionality of migration cannot be unequivocally inferred, the moderate to high levels of genetic variation exhibited by American badgers, alongside the low frequency of haplotypes with indels in the Midwest, suggest a potential recolonization into central North America after the hypothesized ice‐free corridor reopened ~13,000 years ago. Overall, the expanded reconstruction of phylogeographic history of American badgers offers a broader understanding of contemporary range‐wide patterns and identifies unique genetic units that can likely be used to inform conservation of at‐risk populations at the northern periphery. [ABSTRACT FROM AUTHOR]

Pleistocene climate fluctuations had profound influence on the biogeographical history of many biota. As large areas in high mountain ranges were covered by glaciers, biota were forced either to peripheral refugia (and possibly beyond to lowland refugia) or to interior refugia (nunataks). However, nunatak survival remains controversial as it relies solely on correlative genetic evidence. Here, we test hypotheses of glacial survival using two high alpine plant species (the insect‐pollinated Pedicularis asplenifolia and wind‐pollinated Carex fuliginosa) in the European Alps. Employing the iDDC (integrative Distributional, Demographic and Coalescent) approach, which couples species distribution modelling, spatial and temporal demographic simulation and Approximate Bayesian Computation, we explicitly test three hypotheses of glacial survival: (a) peripheral survival only, (b) nunatak survival only and (c) peripheral plus nunatak survival. In P. asplenifolia the peripheral plus nunatak survival hypothesis was supported by Bayes factors (BF> 100), whereas in C. fuliginosa the peripheral survival only hypothesis, although best supported, could not be unambiguously distinguished from the peripheral plus nunatak survival hypothesis (BF = 5.58). These results are consistent with current habitat preferences (P. asplenifolia extends to higher elevations) and the potential for genetic swamping (i.e., replacement of local genotypes via hybridization with immigrating genotypes [expected to be higher in the wind‐pollinated C. fuliginosa]). Although the persistence of plants on nunataks during glacial periods has been debated and studied over decades, this is one of the first studies to explicitly test the hypothesis instead of solely using correlative evidence. [ABSTRACT FROM AUTHOR]

The area of the eastern Kamnik-Savinja Alps was glaciated in the time of the Last Pleistocene Glacial Maximum (LGM). The glacial landforms mentioned by the previous researchers and other landforms in the area were examined, gemorphologically mapped, morphographically and morphometrically analysed and a new map of the extent of the LGM was produced. The research revealed several glaciers in the area and that their sizes differed, primarily depending on the slope inclination direction.

Aim: Understanding the drivers of speciation within islands is key to explain the high levels of invertebrate diversification and endemism often observed within islands. Here, we propose an insular topoclimate model for Quaternary diversification (ITQD), and test the general prediction that, within a radially eroded conical island, glacial climate conditions facilitate the divergence of populations within species across valleys. Location: Gran Canaria, Canary Islands. Taxon: The Laparocerus tessellatus beetle species complex (Coleoptera, Curculionidae). Methods: We characterize individual‐level genomic relationships using single nucleotide polymorphisms produced by double‐digest restriction site associated DNA sequencing (ddRAD‐seq). A range of parameter values were explored in order to filter our data. We assess individual relatedness, species boundaries, demographic history and spatial patterns of connectivity. Results: The total number of ddRAD‐seq loci per sample ranges from 4,576 to 512, with 11.12% and 4.84% of missing data respectively, depending on the filtering parameter combination. We consistently infer four genetically distinct ancestral populations and two presumed cases of admixture, one of which is largely restricted to high altitudes. Bayes factor delimitation support the hypothesis of four species, which is consistent with the four inferred ancestral gene pools. Landscape resistance analyses identified genomic relatedness among individuals in two out of the four inferred species to be best explained by annual precipitation during the last glacial maximum rather than geographic distance. Main conclusions: Our data reveal a complex speciation history involving population isolation and admixture, with broad support for the ITQD model here proposed. We suggest that further studies are needed to test the generality of our model, and enrich our understanding of the evolutionary process in island invertebrates. Our results demonstrate the power of ddRAD‐seq data to provide a detailed understanding of the temporal and spatial dynamics of insular biodiversity. [ABSTRACT FROM AUTHOR]

To predict evolutionary processes, such as speciation and local adaptation, we need to understand the mechanisms causing genetic differentiation of populations. We used mitochondrial control region sequence variation to investigate the genetic structure within and between Atlantic and Pacific populations of Black-legged Kittiwake (Rissa t. tridactyla and R. t. pollicaris, respectively). We predicted that genetic divergence of these populations, as in other northern hemisphere seabird species, might have been caused by glacial vicariance in the late Pleistocene. Further, because of regional differences in the morphology of kittiwakes, and the hypothesized historical vicariance, we predicted that genetic structure would exist within Atlantic but not Pacific populations. Population genetic and phylogenetic analyses of 756 base pairs of control region sequence for 398 kittiwakes indicated that Atlantic and Pacific populations are genetically differentiated from one another. Phylogenetic analyses indicated historical divergence of two mtDNA clades within the Pacific population and four mtDNA clades within the Atlantic population. Population genetic analyses indicated that colonies within the Atlantic were strongly differentiated from one another, which could be explained by restrictions in contemporary gene flow and historical fragmentation in historical refugia. Population genetic analyses provided little evidence for genetic structure in the Pacific population, which we attributed to longer time since vicariance, allowing more migration between colonies. Our results agree with current subspecies designations of Atlantic and Pacific populations. [ABSTRACT FROM AUTHOR]

Documentation of intraspecific genetic lineages and their evolutionary history can provide insight for current and future conservation and management actions. The Blanding's Turtle, Emys (= Emydoidea) blandingii, is a long-lived species with a relatively narrow latitudinal distribution centered around the Great Lakes, but extending from Nebraska to Nova Scotia. It is listed as endangered or threatened throughout most of its range mainly due to habitat loss. Microsatellite loci have been predominantly used to test and generate hypotheses concerning the number of evolutionarily significant units and the history of lineage diversification in this species. Here we describe haplotypes from two mitochondrial and three nuclear loci generated from 32 localities across the species' range to provide an additional perspective on existing patterns. Haplotype and nucleotide diversity were low in both sets of loci, with mitochondrial polymorphism comparable to the lowest found in any North American freshwater turtle. Spatial analyses of population differentiation supported the presence of two groups with a boundary in eastern Ontario that is roughly associated with the Appalachian Mountains as proposed by Mockford et al. (Conserv Gen 8:209–219, 2007). We suggest that the low diversity in these loci is likely related to periodic range contractions and expansions associated with glacial cycles and that the two groups recovered result from a deeper history of diversification. Our results are broadly consistent with previously identified range-wide structure and help to reconcile population structure found at smaller spatial scales, outcomes that will better inform conservation decision making for the species. [ABSTRACT FROM AUTHOR]

The spatial distribution of biodiversity and related processes is the core of Biogeography. Amazonia is the world's most diverse rainforest and the primary source of diversity to several Neotropical regions. The origins of such diversity continue to be an unresolved question in evolutionary biology. Among many competing hypotheses to explain the evolution of the Amazonian biodiversity, one stands out as the most influential: the refugia hypothesis by Jürgen Haffer. Here, we provide a chronological overview on how the refugia hypothesis evolved over the decades and how the criticism from different fields affected its acceptance. We conclude that the refugia hypothesis alone cannot explain the diversification of the complex Amazonian diversity, and perhaps it was not the most important diversification mechanism. However, the debate provoked by refugia has produced a great amount of knowledge on Amazonian climatic, geological, and evolutionary processes, as well as on species distributions, movements, and history. [ABSTRACT FROM AUTHOR]

To better assess the spatiotemporal variations of the snow shielding effect on surface exposure dating, we compiled a dataset of 1341 10Be ages from alpine moraines and glacially eroded valleys across western North America, and conducted a sensitivity test with both modern and time-integrated snow data covering the same region. Our analyses reveal significant differences in snow shielding both across our geographic domain and through time. In our time-integrated experiments we find snow-based exposure age corrections as low as 3.5% in the Great Basin region and high as 28.4% in the Pacific Northwest for samples dating to the Last Glacial Maximum (LGM) when no wind-sweeping is assumed. As demonstrated with our time-varying snow conditions with a global climate model and a positive degree day model, modern snow conditions across western North America cannot account for the varying snow patterns under large scale climate shifts since the LGM. The snow-based exposure age corrections from the modern data differ from those calculated by our time-varying model by up to 17% across our model domain. In addition, we find that the 10Be ages calculated under two end-member scenarios regarding wind-sweeping effects, specifically whether boulders were shielded only when the total snow accumulation exceeded boulder heights or were always shielded when the snow was present, can differ by ∼7.6% on average for LGM aged samples. Our analyses provide a model-based estimates of the spatiotemporal variability and complexity of snow shielding effects on surface exposure dates across western North America and highlight the need to consider snow depth variations both spatially and temporally when conducting surface exposure dating in terrains where snowfall accumulation is significant. [ABSTRACT FROM AUTHOR]

Along the terrestrial margin of the southern North Sea, previous studies of the MIS 2 glaciation impacting eastern Britain have played a significant role in the development of principles relating to ice sheet dynamics (e.g. deformable beds), and the practice of reconstructing the style, timing, and spatial configuration of palaeo-ice sheets. These detailed terrestrially-based findings have however relied on observations made from only the outer edges of the former ice mass, as the North Sea Lobe (NSL) of the British-Irish Ice Sheet (BIIS) occupied an area that is now almost entirely submarine (c.21–15 ka). Compounded by the fact that marine-acquired data have been primarily of insufficient quality and density, the configuration and behaviour of the last BIIS in the southern North Sea remains surprisingly poorly constrained. This paper presents analysis of a new, integrated set of extensive seabed geomorphological and seismo-stratigraphic observations that both advances the principles developed previously onshore (e.g. multiple advance and retreat cycles), and provides a more detailed and accurate reconstruction of the BIIS at its southern-most extent in the North Sea. A new bathymetry compilation of the region reveals a series of broad sedimentary wedges and associated moraines that represent several terminal positions of the NSL. These former still-stand ice margins (1–4) are also found to relate to newly-identified architectural patterns (shallow stacked sedimentary wedges) in the region's seismic stratigraphy (previously mapped singularly as the Bolders Bank Formation). With ground-truthing constraint provided by sediment cores, these wedges are interpreted as sub-marginal till wedges, formed by complex subglacial accretionary processes that resulted in till thickening towards the former ice-sheet margins. The newly sub-divided shallow seismic stratigraphy (at least five units) also provides an indication of the relative event chronology of the NSL. While there is a general record of south-to-north retreat, seismic data also indicate episodes of ice-sheet re-advance suggestive of an oscillating margin (e.g. MIS 2 maximum not related to first incursion of ice into region). Demonstrating further landform interdependence, geographically-grouped sets of tunnel valleys are shown to be genetically related to these individual ice margins, providing clear insight into how meltwater drainage was organised at the evolving termini of this dynamic ice lobe. The newly reconstructed offshore ice margins are found to be well correlated with previously observed terrestrial limits in Lincolnshire and E. Yorkshire (Holderness) (e.g. MIS 2 maximum and Withernsea Till). This reconstruction will hopefully provide a useful framework for studies targeting the climatic, mass-balance, and external glaciological factors (i.e. Fennoscandian Ice Sheet) that influenced late-stage advance and deglaciation, important for accurately characterising both modern and palaeo-ice sheets. [ABSTRACT FROM AUTHOR]

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Wild soybean (Glycine soja Sieb. & Zucc.), the progenitor of cultivated soybean (Glycine max (L.) Merr.), is widely distributed in the Sino-Japanese Floristic Region (SJFR). Therefore, it is an excellent model organism to study the effect of Quaternary climatic changes on the distribution and migration of plant taxa in the SJFR. To investigate the phylogeography of G. soja, a total of 632 individuals representing 52 populations throughout the species distribution range were genotyped by using the sequencing data of a nuclear locus, AF105221, and a chloroplast locus, trnQ-rps16. We detected a total of 23 haplotypes from two loci, including five common and 18 rare haplotypes. Among them, 17 rare haplotypes were limited to Northeast Asia (Northeast China (NEC) and Korea) and the Yangzi River basin (middle and downstream of the Yangzi River (MDYR) and the eastern end of Southwest China (SWC)). Moreover, two common haplotypes were detected throughout the species distribution wide range. All the haplotypes from Japan and the Korean peninsula were also found in China. The haplotype distribution patterns of the two loci suggested that Northeast Asia (NEC and Korea) and the Yangzi River basin (MDYR and the eastern end of SWC) might have been the refugia for G. soja during the Quaternary glacial period, and G. soja expanded rapidly after the end of the Last Glacial Maximum. There was a land bridge between East China, the Korean peninsula, and Japan that permitted gene flow among populations of these regions in the ice age during the Quaternary. [ABSTRACT FROM AUTHOR]

It is widely recognised that arid Australia (including semi- and seasonally arid regions) supports an extremely diverse ant fauna. However, the truly remarkable extent of its diversity is not well appreciated, even among myrmecologists, and the reasons for such diversity are poorly understood. The vast majority of ant species in arid Australia are undescribed, and I argue that a recognition of the true diversity of the fauna would re-define the conventional understanding of global ant diversity patterns. For example, Monomorium Mayr and Tetramorium Mayr are formally recognised as widespread but essentially Afrotropical genera, whereas the large majority of species actually occur in arid Australia. The Australian fauna includes many genera each with >100 arid-adapted species, and several of these have >300 species. Melophorus Lubbock is likely to have well over 1000 species, making it one of the world's richest ant genera despite being endemic to Australia. I estimate that the total size of the ant fauna of arid Australia is as much as 7500 species, which would make it rival, if not surpass, that of the Amazon basin. I argue that the phenomenal ant diversity of arid Australia is a product of its unique history of aridity and associated patterns of speciation and extinction over the past few million years. I propose that the Pleistocene glaciations that caused waves of mass extinctions throughout the northern hemisphere actually promoted speciation in Australia. Australia remained relatively warm during glacial periods, but there was massive movement of sand during these times of peak aridity, with up to 85% of the continent covered by desert dunes. This would have resulted in a highly fragmented biota confined to a very large number of isolated refugia, providing the perfect storm for speciation. [ABSTRACT FROM AUTHOR]

Solitary limestone blocks and groups of blocks occur on Risnjak and Velebit Mountains and on the northern Adriatic islands of Krk and Rab. Previous researchers have interpreted some of these as a) erratic blocks, b) corrosional remnants, or c) rockfalls. We have studied their mode of occurrence and composition, and revised previous interpretations of their origin in the light of transport mechanism and depositional processes. After analyzing the context of the block positions and the physical processes responsible for their emplacement, and taking into account their sedimentological context (their association with glaciogenic sediments), we herein propose a glacial origin for most of these blocks. However, some blocks are indeed shaped by sub-soil corrosion, as evidenced by their structure. The interpreted erratic blocks on the inner northern Adriatic Sea islands document the presence of middle Pleistocene glaciation of Dinaric Mountains though not its maximal extent, which is still unclear as the ice terminus was in the area that is inundated by postglacial rise of Adriatic Sea. The reconstructed ice cap area, which extended along the coastal mountains from Risnjak Mt. to south Velebit Mt. and across the range from Lika Polje to Rab Island, is conservatively estimated to be 5400 km 2 . [ABSTRACT FROM AUTHOR]

During the last 15-20 years, phylogenetic, phylogeographic, paleontological, geological, and habitat modeling studies have improved our knowledge of Sundaic biogeography dramatically. In light of these advances, we review (or postulate) where Sundaic rainforest birds came from, the causes of their endemism, and the influence of Pleistocene climatic perturbations on their diversification. We suggest that four scenarios make up a coherent, plausible explanation of patterns of extant diversity. First, relictual lineages, which represent hangovers from the warm, wet Eocene, survived the hard climatic times of the colder, drier Oligocene and Pliocene in the mountains and adjacent lowlands of eastern Borneo, where rainforest has existed continuously for the last 20-30 million years. Second, most modern SE Asian genera developed during the Miocene. Third, the rainforest of Sundaland and its avifauna were largely isolated from the rest of SE Asia during the late Miocene and Pliocene by seasonal habitats in southern Indochina and ocean boundaries elsewhere, increasing regional endemism. Finally, the advent of global glaciation in the Pleistocene introduced a different diversification dynamic to Sundaland. Early glacial events caused sufficient drying in central Sundaland to fragment rainforest and its avifauna into refugia in eastern and western Sundaland and to allow dry-habitat taxa to reach Java from Indochina. More recent glacial events resulted in sufficient perhumid habitat in central Sundaland to reconnect previously vicariated rainforest populations, creating the lowland and elevational parapatry we see today. This Pleistocene dynamic was probably not simply one period of separation and one period of connection, but rather a complex interplay of isolation and colonization, influenced by highly variable population sizes, changing levels of gene flow, and behavioral idiosyncrasies of the species involved. Throughout all of these events, Borneo played a seminal role in rainforest bird evolution by providing the habitat necessary for diversification and the long-term survival of taxa. [ABSTRACT FROM AUTHOR]