Gene flow and an anomaly zone complicate phylogenomic inference in a rapidly radiated avian family (Prunellidae).

BACKGROUND: Resolving the phylogeny of rapidly radiating lineages presents a challenge when building the Tree of Life. An Old World avian family Prunellidae (Accentors) comprises twelve species that rapidly diversified at the Pliocene-Pleistocene boundary. RESULTS: Here we investigate the phylogenetic relationships of all species of Prunellidae using a chromosome-level de novo assembly of Prunella strophiata and 36 high-coverage resequenced genomes. We use homologous alignments of thousands of exonic and intronic loci to build the coalescent and concatenated phylogenies and recover four different species trees. Topology tests show a large degree of gene tree-species tree discordance but only 40-54% of intronic gene trees and 36-75% of exonic genic trees can be explained by incomplete lineage sorting and gene tree estimation errors. Estimated branch lengths for three successive internal branches in the inferred species trees suggest the existence of an empirical anomaly zone. The most common topology recovered for species in this anomaly zone was not similar to any coalescent or concatenated inference phylogenies, suggesting presence of anomalous gene trees. However, this interpretation is complicated by the presence of gene flow because extensive introgression was detected among these species. When exploring tree topology distributions, introgression, and regional variation in recombination rate, we find that many autosomal regions contain signatures of introgression and thus may mislead phylogenetic inference. Conversely, the phylogenetic signal is concentrated to regions with low-recombination rate, such as the Z chromosome, which are also more resistant to interspecific introgression. CONCLUSIONS: Collectively, our results suggest that phylogenomic inference should consider the underlying genomic architecture to maximize the consistency of phylogenomic signal.

The evolution of ancestral and species-specific adaptations in snowfinches at the Qinghai-Tibet Plateau.

Species in a shared environment tend to evolve similar adaptations under the influence of their phylogenetic context. Using snowfinches, a monophyletic group of passerine birds (Passeridae), we study the relative roles of ancestral and species-specific adaptations to an extreme high-elevation environment, the Qinghai-Tibet Plateau. Our ancestral trait reconstruction shows that the ancestral snowfinch occupied high elevations and had a larger body mass than most nonsnowfinches in Passeridae. Subsequently, this phenotypic adaptation diversified in the descendant species. By comparing high-quality genomes from representatives of the three phylogenetic lineages, we find that about 95% of genes under positive selection in the descendant species are different from those in the ancestor. Consistently, the biological functions enriched for these species differ from those of their ancestor to various degrees (semantic similarity values ranging from 0.27 to 0.5), suggesting that the three descendant species have evolved divergently from the initial adaptation in their common ancestor. Using a functional assay to a highly selective gene, DTL, we demonstrate that the nonsynonymous substitutions in the ancestor and descendant species have improved the repair capacity of ultraviolet-induced DNA damage. The repair kinetics of the DTL gene shows a twofold to fourfold variation across the ancestor and the descendants. Collectively, this study reveals an exceptional case of adaptive evolution to high-elevation environments, an evolutionary process with an initial adaptation in the common ancestor followed by adaptive diversification of the descendant species.

Patterns of phylogenetic diversification in the Dollarbird (Eurystomus orientalis) and Azure Roller (Eurystomus azureus) complex.

Genetic isolation and morphological differentiation are two important factors in the speciation process that not always act in concert. A rapid morphological change in a lineage can hide its close relationship to another lineage, while slight morphological differentiation between two taxa can give the appearance of a closer relationship than is actually the case. The Dollarbird (Eurystomus orientalis) and the Azure Roller (Eurystomus azureus) is such an example. Today the Dollarbird and the Azure Roller are unanimously considered to constitute two distinct species, but in a recent genetic study it has been shown that the latter taxon, despite being larger and having a distinctly different coloration, is phylogenetically nested within the former. Its precise placement within this complex has not been determined, however. In this study, we investigate the phylogenetic relationships within the Dollarbird/Azure Roller complex. We estimate divergence times and infer phylogenetic relationships using sequence data from 6,475 genome-wide intronic regions, as well as complete mitochondrial genomes, using both concatenation and multispecies coalescence approaches. We find that within the Dollarbird/Azure Roller complex there are several examples of discrepancies between genetic and morphological differentiation. The Dollarbird is currently divided into between nine to twelve subspecies. Some of these subspecies are poorly differentiated, whereas others are morphologically more clearly discernable. Our data suggest that the complex consist of at least seven distinct genetic lineages that do not entirely match the morphological variation within the group. For instance, our results show that the subspecies solomonensis from the Solomon Islands, despite being morphologically very similar to its geographically closest neighbors, in fact is a highly distinct lineage that became isolated more than 700,000 years ago. In contrast, the morphologically distinct Azure Roller, which is currently treated as a distinct species, is nested within the Dollarbird and forms a slightly younger lineage than solomonensis and is the sister group to a clade with Australian and New Guinean Dollarbirds. Our results also show a deep genetic split within the Dollarbirds on the Asian mainland. This stands in contrast to the apparent clinal morphological variation reported for the birds on the Asian mainland. We also find support for the presence of a genetically distinct clade in the Wallacea region. The birds from the Wallacea region has previously been recognized as a distinct subspecies, connectens, but is currently placed in synonymy of other subspecies. Our results are thus at odds with the current division of the Dollarbird/Azure Roller complex into two species. Given that the species status of azureus is undisputed, the apparent genetic isolation of solomonensis and its clear separation from the other lineages suggests that this taxon also warrants species status. Based on the genetic and morphological variation observed within the Dollarbird/Azure Roller complex there is little doubt that even more taxa should regarded as species, but this require further examination.

Utilizing museomics to trace the complex history and species boundaries in an avian-study system of conservation concern.

A taxonomic classification that accurately captures evolutionary history is essential for conservation. Genomics provides powerful tools for delimiting species and understanding their evolutionary relationships. This allows for a more accurate and detailed view on conservation status compared with other, traditionally used, methods. However, from a practical and ethical perspective, gathering sufficient samples for endangered taxa may be difficult. Here, we use museum specimens to trace the evolutionary history and species boundaries in an Asian oriole clade. The endangered silver oriole has long been recognized as a distinct species based on its unique coloration, but a recent study suggested that it might be nested within the maroon oriole-species complex. To evaluate species designation, population connectivity, and the corresponding conservation implications, we assembled a de novo genome and used whole-genome resequencing of historical specimens. Our results show that the silver orioles form a monophyletic lineage within the maroon oriole complex and that maroon and silver forms continued to interbreed after initial divergence, but do not show signs of recent gene flow. Using a genome scan, we identified genes that may form the basis for color divergence and act as reproductive barriers. Taken together, our results confirm the species status of the silver oriole and highlight that taxonomic revision of the maroon forms is urgently needed. Our study demonstrates how genomics and Natural History Collections (NHC) can be utilized to shed light on the taxonomy and evolutionary history of natural populations and how such insights can directly benefit conservation practitioners when assessing wild populations.

Parallel Evolution of Bower-Building Behavior in Two Groups of Bowerbirds Suggested by Phylogenomics.

The bowerbirds in New Guinea and Australia include species that build the largest and perhaps most elaborately decorated constructions outside of humans. The males use these courtship bowers, along with their displays, to attract females. In these species, the mating system is polygynous and the females alone incubate and feed the nestlings. The bowerbirds also include 10 species of the socially monogamous catbirds in which the male participates in most aspects of raising the young. How the bower-building behavior evolved has remained poorly understood, as no comprehensive phylogeny exists for the family. It has been assumed that the monogamous catbird clade is sister to all polygynous species. We here test this hypothesis using a newly developed pipeline for obtaining homologous alignments of thousands of exonic and intronic regions from genomic data to build a phylogeny. Our well-supported species tree shows that the polygynous, bower-building species are not monophyletic. The result suggests either that bower-building behavior is an ancestral condition in the family that was secondarily lost in the catbirds, or that it has arisen in parallel in two lineages of bowerbirds. We favor the latter hypothesis based on an ancestral character reconstruction showing that polygyny but not bower-building is ancestral in bowerbirds, and on the observation that Scenopoeetes dentirostris, the sister species to one of the bower-building clades, does not build a proper bower but constructs a court for male display. This species is also sexually monomorphic in plumage despite having a polygynous mating system. We argue that the relatively stable tropical and subtropical forest environment in combination with low predator pressure and rich food access (mostly fruit) facilitated the evolution of these unique life-history traits. [Adaptive radiation; bowerbirds; mating system, sexual selection; whole genome sequencing.].

Genomic signatures of rapid adaptive divergence in a tropical montane species.

Mountain regions contain extraordinary biodiversity. The environmental heterogeneity and glacial cycles often accelerate speciation and adaptation of montane species, but how these processes influence the genomic differentiation of these species is largely unknown. Using a novel chromosome-level genome and population genomic comparisons, we study allopatric divergence and selection in an iconic bird living in a tropical mountain region in New Guinea, Archbold's bowerbird (Amblyornis papuensis). Our results show that the two populations inhabiting the eastern and western Central Range became isolated ca 11 800 years ago, probably because the suitable habitats for this cold-tolerating bird decreased when the climate got warmer. Our genomic scans detect that genes in highly divergent genomic regions are over-represented in developmental processes, which is probably associated with the observed differences in body size between the populations. Overall, our results suggest that environmental differences between the eastern and western Central Range probably drive adaptive divergence between them.

Genomic differentiation tracks earth-historic isolation in an Indo-Australasian archipelagic pitta (Pittidae; Aves) complex.

BACKGROUND: Allopatric speciation has played a particularly important role in archipelagic settings where populations evolve in isolation after colonizing different islands. The Indo-Australasian island realm is an unparalleled natural laboratory of biotic diversification. Here we explore how the level of earth-historic isolation has influenced genetic differentiation across the region by investigating phylogeographic patterns in the Pitta sordida species complex. RESULTS: We generated a de novo genome and compared population genomics of 29 individuals of Pitta sordida from the entire distributional range and we reconstructed phylogenetic relationship using mitogenomes, a multi-nuclear gene dataset and single nucleotide polymorphisms (SNPs). We found deep divergence between an eastern and a western group of taxa across Indo-Australasia. Within both groups we have identified major lineages that are geographically separated into Philippines, Borneo, western Sundaland, and New Guinea, respectively. Although these lineages are genetically well-differentiated, suggesting a long-term isolation, there are signatures of extensive gene flow within each lineage throughout the Pleistocene, despite the wide geographic range occupied by some of them. We found little evidence of hybridization or introgression among the studied taxa, but forsteni from Sulawesi makes an exception. This individual, belonging to the eastern clade, is genetically admixed between the western and eastern clades. Geographically this makes sense as Sulawesi is not far from Borneo that houses a population of hooded pittas that belongs to the western clade. CONCLUSIONS: We found that geological vicariance events cannot explain the current genetic differentiation in the Pitta sordida species complex. Instead, the glacial-interglacial cycles may have played a major role therein. During glacials the sea level could be up to 120 m lower than today and land bridges formed within both the Sunda Shelf and the Sahul Shelf permitting dispersal of floral and faunal elements. The geographic distribution of hooded pittas shows the importance of overwater, "stepping-stone" dispersals not only to deep-sea islands, but also from one shelf to the other. The most parsimonious hypothesis is an Asian ancestral home of the Pitta sordida species complex and a colonization from west to east, probably via Wallacea.

Complete subspecies-level phylogeny of the Oriolidae (Aves: Passeriformes): Out of Australasia and return.

Old World orioles (Oriolidae) are medium-sized passerine birds confined largely to forested areas of Africa, Eurasia and Australasia. We present a new complete molecular (mtDNA) subspecies level phylogeny of the Oriolidae including all 113 taxa (35 species) together with a backbone phylogeny of 19 taxa from the main Oriolus clades based on (i) 21 nuclear genes, (ii) whole mito-genomes, and (iii) genome-wide ultraconserved elements. We use this phylogeny to assess systematic relationships and the biogeographical history of this avian family. Furthermore, we use morphological measurements to investigate the relationship between size and shape axes and upstream or back-colonization of this extensive island region from Asia. We show that several subspecies or groups of subspecies may warrant species rank and we find a continental example of two morphologically distinct species (O. mellianus/O. traillii) being genetically (mtDNA) very similar. Biogeographically, we confirm previous findings that members of the Oriolidae originated in Australo-Papua. Dispersal out of this area took place around 15 Mya to southeast Asia and Africa, and from Africa to the Palearctic followed by recolonization of the Indonesian and Philippine island region during the Plio-Pleistocene. Recolonisation of the Indonesian and Philippine islands coincided with an increase in body size, which may have facilitated the ability to co-exist with other congenerics.

Near-complete phylogeny and taxonomic revision of the world's babblers (Aves: Passeriformes).

The babblers are a diverse group of passerine birds comprising 452 species. The group was long regarded as a "scrap basket" in taxonomic classification schemes. Although several studies have assessed the phylogenetic relationships for subsets of babblers during the past two decades, a comprehensive phylogeny of this group has been lacking. In this study, we used five mitochondrial and seven nuclear loci to generate a dated phylogeny for babblers. This phylogeny includes 402 species (ca. 89% of the overall clade) from 75 genera (97%) and all five currently recognized families, providing a robust basis for taxonomic revision. Our phylogeny supports seven major clades and reveals several non-monophyletic genera. Divergence time estimates indicate that the seven major clades diverged around the same time (18-20 million years ago, Ma) in the early Miocene. We use the phylogeny in a consistent way to propose a new taxonomy, with seven families and 64 genera of babblers, and a new linear sequence of names.

Phylogenetic relationships of rollers (Coraciidae) based on complete mitochondrial genomes and fifteen nuclear genes.

The rollers (Coraciidae) constitute a relative small avian family with ca. 12 species distributed in Africa, western and southern Eurasia, and eastern Australia. In this study we examine the phylogenetic relationships of all species currently recognized in the family, including two taxa whose taxonomic status is currently contested. By using shotgun sequencing on degraded DNA from museum study skins we have been able to recover complete mitochondrial genomes as well as 15 nuclear genes for in total 16 taxa. The gene sequences were analyzed both concatenated in a maximum likelihood framework as well in a species tree approach using MP-EST. The different analytical approaches yield similar, highly supported trees and support the current division of the rollers into two genera, Coracias and Eurystomus. The only conflict relates to the placement of the Blue-bellied Roller (C. cyanogaster), where the mitochondrial, and the concatenated nuclear and mitochondrial data set, place this taxon as sister to the other Coracias species, whereas nuclear data and the species tree analysis place it as the sister taxon of C. naevia and C. spatulatus. All analyses place the Eurasian roller (C. garrulus) with the two African species, Abyssinian Roller (C. abyssinica) and Liliac-breasted Roller (C. caudatus), and place this clade as the sister group to the Asian Coracias rollers. In addition, our results support a sister group relationship between the morphologically rather dissimilar Purple Roller (C. naevia) and Racquet-tailed Roller (C. spatulatus) and also support the division of Eurystomus in an African and an Asian clade. However, within the Asian clade the Azure Roller (E. azureus) from Halmahera appears to be nested within the Dollarbird (E. orientalis), indicating that that this taxon is a morphological divergent, but a rather recent offshoot, of the widespread Dollarbird. Similarly, the Purple-winged Roller (C. temminickii) from Sulawesi group together with C. benghalensis affinis from Southeast Asia and these two in turn comprises the sister group to C. benghalensis benghalensis from India and western Asia.

Relicts of the lost arc: High-throughput sequencing of the Eutrichomyias rowleyi (Aves: Passeriformes) holotype uncovers an ancient biogeographic link between the Philippines and Fiji.

Molecular studies have revealed a number of cases in which traditional assessments of evolutionary relationships have been incorrect. This has implications not only for systematics and taxonomy but also for our understanding of how diversity patterns on Earth have been formed. Here, we use high-throughput sequencing technology to obtain molecular data from the holotype specimen of the elusive Eutrichomyias rowleyi, which is endemic to the Indonesian island of Sangihe. We show that E. rowleyi unexpectedly is a member of the family Lamproliidae, which dates back some 20 Million years and only include two other species, Lamprolia victoriae from Fiji and Chaetorhynchus papuensis from New Guinea. Tectonic reconstructions suggest that the Melanesian island arc, which included land masses on the northern edge of the Australian plate (present day New Guinea) stretched as a string of islands from the Philippines (including proto-Sangihe) to Fiji from 25 to 20 My. Consequently, our results are indicative of an ancient distribution along the Melanesian island arc followed by relictualization, which led to members of the Lamproliidae to be distributed on widely separated islands across the Indo-Pacific.

Complete species-level phylogeny of the leaf warbler (Aves: Phylloscopidae) radiation.

The leaf warbler radiation (Aves: Phylloscopidae) has undergone a c. 50% increase in the number of recognised species over the last three decades, mainly as a result of analyses of vocalisations and DNA. Using a multilocus dataset for all of the species in this family, and multispecies coalescent-based as well as concatenation methods, we provide the first complete species-level phylogeny for this important group, as well as an estimate of the timing of diversification. The most recent common ancestor for the family was dated at 11.7 million years ago (mya) (95% highest posterior density 9.8-13.7 mya), and divergence times between sister species ranged from 0.5 mya (0.3-0.8 mya) to 6.1 mya (4.8-7.5 mya). Based on our results, we support synonymising Seicercus with Phylloscopus, which results in a monogeneric Phylloscopidae. We discuss the pros and cons of this treatment,and we argue againstproliferation of taxonomic names,and conclude that a large monogeneric Phylloscopidae leads to the fewest taxonomic changes compared to traditional classifications. We briefly discuss morphological evolution in the light of the phylogeny. The time calibrated phylogeny is a major improvement compared to previous studies based on a smaller number of species and loci and can provide a basis for future studies of other aspects of phylloscopid evolution.

The evolution of mimicry of friarbirds by orioles (Aves: Passeriformes) in Australo-Pacific archipelagos.

Observations by Alfred Wallace and Jared Diamond of plumage similarities between co-occurring orioles (Oriolus) and friarbirds (Philemon) in the Malay archipelago led them to conclude that the former represent visual mimics of the latter. Here, we use molecular phylogenies and plumage reflectance measurements to test several key predictions of the mimicry hypothesis. We show that friarbirds originated before brown orioles, that the two groups did not co-speciate, although there is one plausible instance of co-speciation among species on the neighbouring Moluccan islands of Buru and Seram. Furthermore, we show that greater size disparity between model and mimic and a longer history of co-occurrence have resulted in a stronger plumage similarity (mimicry). This suggests that resemblance between orioles and friarbirds represents mimicry and that colonization of islands by brown orioles has been facilitated by their ability to mimic the aggressive friarbirds.

The complex phylogeography of the Indo-Malayan Alophoixus bulbuls with the description of a putative new ring species complex.

The Indo-Malayan bioregion has provided some of the most spectacular discoveries of new vertebrate species (e.g. saola, khanyou, bare-faced bulbul) over the last 25 years. Yet, very little is known about the processes that led to the current biodiversity in this region. We reconstructed the phylogeographic history of a group of closely related passerines, the Alophoixus bulbuls. These birds are continuously distributed in Indo-Malaya around the Thailand lowlands such that their distribution resembles a ring. Our analyses revealed a single colonization event of the mainland from Sundaland with sequential divergence of taxa from southwest to northeast characterized by significant gene flow between parapatric taxa, and reduced or ancient gene flow involving the two taxa at the extremities of the ring. We detected evidence of population expansion in two subspecies, including one that was involved in the closing of the ring. Hence, our analyses indicate that the diversification pattern of Alophoixus bulbuls fits a ring species model driven by geographic isolation. To our knowledge, the Alophoixus bulbuls represent the first case of a putative broken ring species complex in Indo-Malaya. We also discuss the implications of our results on our understanding of the biogeography in Indo-Malaya.

Ecological and evolutionary determinants for the adaptive radiation of the Madagascan vangas.

Adaptive radiation is the rapid diversification of a single lineage into many species that inhabit a variety of environments or use a variety of resources and differ in traits required to exploit these. Why some lineages undergo adaptive radiation is not well-understood, but filling unoccupied ecological space appears to be a common feature. We construct a complete, dated, species-level phylogeny of the endemic Vangidae of Madagascar. This passerine bird radiation represents a classic, but poorly known, avian adaptive radiation. Our results reveal an initial rapid increase in evolutionary lineages and diversification in morphospace after colonizing Madagascar in the late Oligocene some 25 Mya. A subsequent key innovation involving unique bill morphology was associated with a second increase in diversification rates about 10 Mya. The volume of morphospace occupied by contemporary Madagascan vangas is in many aspects as large (shape variation)--or even larger (size variation)--as that of other better-known avian adaptive radiations, including the much younger Galapagos Darwin's finches and Hawaiian honeycreepers. Morphological space bears a close relationship to diet, substrate use, and foraging movements, and thus our results demonstrate the great extent of the evolutionary diversification of the Madagascan vangas.

Dating the diversification of the major lineages of Passeriformes (Aves).

BACKGROUND: The avian Order Passeriformes is an enormously species-rich group, which comprises almost 60% of all living bird species. This diverse order is believed to have originated before the break-up of Gondwana in the late Cretaceous. However, previous molecular dating studies have relied heavily on the geological split between New Zealand and Antarctica, assumed to have occurred 85-82 Mya, for calibrating the molecular clock and might thus be circular in their argument. RESULTS: This study provides a time-scale for the evolution of the major clades of passerines using seven nuclear markers, five taxonomically well-determined passerine fossils, and an updated interpretation of the New Zealand split from Antarctica 85-52 Mya in a Bayesian relaxed-clock approach. We also assess how different interpretations of the New Zealand-Antarctica vicariance event influence our age estimates. Our results suggest that the diversification of Passeriformes began in the late Cretaceous or early Cenozoic. Removing the root calibration for the New Zealand-Antarctica vicariance event (85-52 Mya) dramatically increases the 95% credibility intervals and leads to unrealistically old age estimates. We assess the individual characteristics of the seven nuclear genes analyzed in our study. Our analyses provide estimates of divergence times for the major groups of passerines, which can be used as secondary calibration points in future molecular studies. CONCLUSIONS: Our analysis takes recent paleontological and geological findings into account and provides the best estimate of the passerine evolutionary time-scale currently available. This time-scale provides a temporal framework for further biogeographical, ecological, and co-evolutionary studies of the largest bird radiation, and adds to the growing support for a Cretaceous origin of Passeriformes.

Long-term isolation and stability explain high genetic diversity in the Eastern Himalaya.

China's Southwest Mountainous Region in Eastern Himalaya is a 'biodiversity hotspot' of global interest for conservation. Yet little is known about what has driven this unique diversity. The dramatic topography of the Southwest Mountainous Region resulting from the tectonic uplift during the late Pliocene leads to dramatic ecological stratification, which creates physical barriers to migration and isolates organisms into different subregions and mountain systems. This agrees with the observation that the phylogeographical patterns found in four species of birds (Alcippe morrisonia, Stachyridopsis ruficeps, Parus monticolus and Aegithalos concinnus) distributed in this region are characterized by deep splits between lineages that coalesce between 0.8 and 2.1 Ma. Unlike other regions at this latitude, the Southwest Mountainous Region was largely unaffected by the Pleistocene glaciations. Genetically isolated populations of these birds could thus be maintained throughout the Pleistocene in these rather stable montane environments. In comparison, we found radically different phylogeographical patterns in populations of the same four species distributed in the adjacent lowland, the Central China region. This region has a distinctly different geological history with dramatic, climate-induced shifts in vegetation during the Pleistocene. Here, we found a considerably less geographical structure in the genetic variation and a much younger coalescence time (0.3-0.7 Ma). We also found evidence of genetic bottlenecks during the glacial periods and gene flow during the interglacial expansions. We conclude that the high genetic diversity in the Southwest Mountainous Region results from a long-term in situ diversification within these evolutionary isolated and environment stable montane habitats.

Phylogeny and historical biogeography of gnateaters (Passeriformes, Conopophagidae) in the South America forests.

We inferred the phylogenetic relationships, divergence time and biogeography of Conopophagidae (gnateaters) based on sequence data of mitochondrial genes (ND2, ND3 and cytb) and nuclear introns (TGFB2 and G3PDH) from 45 tissue samples (43 Conopophaga and 2 Pittasoma) representing all currently recognized species of the family and the majority of subspecies. Phylogenetic relationships were estimated by maximum likelihood and Bayesian inference. Divergence time estimates were obtained based on a Bayesian relaxed clock model. These chronograms were used to calculate diversification rates and reconstruct ancestral areas of the genus Conopophaga. The phylogenetic analyses support the reciprocal monophyly of the two genera, Conopophaga and Pittasoma. All species were monophyletic with the exception of C. lineata, as C. lineata cearae did not cluster with the other two C. lineata subspecies. Divergence time estimates for Conopophagidae suggested that diversification took place during the Neogene, and that the diversification rate within Conopophaga clade was highest in the late Miocene, followed by a slower diversification rate, suggesting a diversity-dependent pattern. Our analyses of the diversification of family Conopophagidae provided a scenario for evolution in Terra Firme forest across tropical South America. The spatio-temporal pattern suggests that Conopophaga originated in the Brazilian Shield and that a complex sequence of events possibly related to the Andean uplift and infilling of former sedimentation basins and erosion cycles shaped the current distribution and diversity of this genus.

Species-specific dynamics may cause deviations from general biogeographical predictions - evidence from a population genomics study of a New Guinean endemic passerine bird family (Melampittidae).

The family Melampittidae is endemic to New Guinea and consists of two monotypic genera: Melampitta lugubris (Lesser Melampitta) and Megalampitta gigantea (Greater Melampitta). Both Melampitta species have scattered and disconnected distributions across New Guinea in the central mountain range and in some of the outlying ranges. While M. lugubris is common and found in most montane regions of the island, M. gigantaea is elusive and known from only six localities in isolated pockets on New Guinea with very specific habitats of limestone and sinkholes. In this project, we apply museomics to determine the population structure and demographic history of these two species. We re-sequenced the genomes of all seven known M. gigantaea samples housed in museum collections as well as 24 M. lugubris samples from across its distribution. By comparing population structure between the two species, we investigate to what extent habitat dependence, such as in M. gigantaea, may affect population connectivity. Phylogenetic and population genomic analyses, as well as acoustic variation revealed that M. gigantaea consists of a single population in contrast to M. lugubris that shows much stronger population structure across the island. We suggest a recent collapse of M. gigantaea into its fragmented habitats as an explanation to its unexpected low diversity and lack of population structure. The deep genetic divergences between the M. lugubris populations on the Vogelkop region, in the western central range and the eastern central range, respectively, suggests that these three populations should be elevated to full species level. This work sheds new light on the mechanisms that have shaped the intriguing distribution of the two species within this family and is a prime example of the importance of museum collections for genomic studies of poorly known and rare species.

The spatio-temporal colonization and diversification across the Indo-Pacific by a 'great speciator' (Aves, Erythropitta erythrogaster).

The Indo-Pacific region has arguably been the most important area for the formulation of theories about biogeography and speciation, but modern studies of the tempo, mode and magnitude of diversification across this region are scarce. We study the biogeographic history and characterize levels of diversification in the wide-ranging passerine bird Erythropitta erythrogaster using molecular, phylogeographic and population genetics methods, as well as morphometric and plumage analyses. Our results suggest that E. erythrogaster colonized the Indo-Pacific during the Pleistocene in an eastward direction following a stepping stone pathway, and that sea-level fluctuations during the Pleistocene may have promoted gene flow only locally. A molecular species delimitation test suggests that several allopatric island populations of E. erythrogaster may be regarded as species. Most of these putative new species are further characterized by diagnostic differences in plumage. Our study reconfirms the E. erythrogaster complex as a 'great speciator': it represents a complex of up to 17 allopatrically distributed, reciprocally monophyletic and/or morphologically diagnosable species that originated during the Pleistocene. Our results support the view that observed latitudinal gradients of genetic divergence among avian sister species may have been affected by incomplete knowledge of taxonomic limits in tropical bird species.