Beringia Research Articles

Plastome phylogenomics and historical biogeography of aquatic plant genus Hydrocharis (Hydrocharitaceae)

BackgroundHydrocharis L. and Limnobium Rich. are small aquatic genera, including three and two species, respectively. The taxonomic status, phylogenetic relationships and biogeographical history of these genera have remained unclear, owing to the lack of Central African endemic H. chevalieri from all previous studies. We sequenced and assembled plastomes of all three Hydrocharis species and Limnobium laevigatum to explore the phylogenetic and biogeographical history of these aquatic plants.ResultsAll four newly generated plastomes were conserved in genome structure, gene content, and gene order. However, they differed in size, the number of repeat sequences, and inverted repeat borders. Our phylogenomic analyses recovered non-monophyletic Hydrocharis. The African species H. chevalieri was fully supported as sister to the rest of the species, and L. laevigatum was nested in Hydrocharis as a sister to H. dubia. Hydrocharis-Limnobium initially diverged from the remaining genera at ca. 53.3 Ma, then began to diversify at ca. 30.9 Ma. The biogeographic analysis suggested that Hydrocharis probably originated in Europe and Central Africa.ConclusionBased on the phylogenetic results, morphological similarity and small size of the genera, the most reasonable taxonomic solution to the non-monophyly of Hydrocharis is to treat Limnobium as its synonym. The African endemic H. chevalieri is fully supported as a sister to the remaining species. Hydrocharis mainly diversified in the Miocene, during which rapid climate change may have contributed to the speciation and extinctions. The American species of former Limnobium probably dispersed to America through the Bering Land Bridge during the Miocene.

Phylotranscriptomics of Theaceae: generic-level relationships, reticulation and whole-genome duplication.

Theaceae, with three tribes, nine genera and more than 200 species, are of great economic and ecological importance. Recent phylogenetic analyses based on plastomic data resolved the relationships among the three tribes and the intergeneric relationships within two of those tribes. However, generic-level relationships within the largest tribe, Theeae, were not fully resolved. The role of putative whole-genome duplication (WGD) events in the family and possible hybridization events among genera within Theeae also remain to be tested further. Transcriptomes or low-depth whole-genome sequencing of 57 species of Theaceae, as well as additional plastome sequence data, were generated. Using a dataset of low-copy nuclear genes, we reconstructed phylogenetic relationships using concatenated, species tree and phylogenetic network approaches. We further conducted molecular dating analyses and inferred possible WGD events by examining the distribution of the number of synonymous substitutions per synonymous site (Ks) for paralogues in each species. For plastid protein-coding sequences , phylogenies were reconstructed for comparison with the results obtained from analysis of the nuclear dataset. Based on the 610 low-copy nuclear genes (858 606 bp in length) investigated, Stewartieae was resolved as sister to the other two tribes. Within Theeae, the Apterosperma-Laplacea clade grouped with Pyrenaria, leaving Camellia and Polyspora as sister. The estimated ages within Theaceae were largely consistent with previous studies based mainly on plastome data. Two reticulation events within Camellia and one between the common ancestor of Gordonia and Schima were found. All members of the tea family shared two WGD events, an older At-γ and a recent Ad-β; both events were also shared with the outgroups (Diapensiaceae, Pentaphylacaceae, Styracaceae and Symplocaceae). Our analyses using low-copy nuclear genes improved understanding of phylogenetic relationships at the tribal and generic levels previously proposed based on plastome data, but the phylogenetic position of the Apterosperma-Laplacea clade needs more attention. There is no evidence for extensive intergeneric hybridization within Theeae or for a Theaceae-specific WGD event. Land bridges (e.g. the Bering land bridge) during the Late Oligocene may have permitted the intercontinental plant movements that facilitated the putative ancient introgression between the common ancestor of Gordonia and Schima.

Conflicting nuclear and mitogenome phylogenies reveal ancient mitochondrial replacement between two North American species of collared lemmings (Dicrostonyx groenlandicus, D. hudsonius)

Collared lemmings (Dicrostonyx) are cold adapted rodents, keystone animals in the tundra communities and the model taxa in studies of Arctic genetic diversity and Quaternary paleontology. We examined mitochondrial and nuclear genomic variation to reconstruct phylogenetic relationships among the Eurasian D. torquatus and North American D. groenlandicus, D. hudsonius and evaluate biogeographic hypothesis of the two colonization events of North America from Eurasia based on morphological variation in dental traits. The nuclear and mitogenome phylogenies support reciprocal monophyly of each species but reveal conflicting relationships among species. The mitogenome tree likely reflects ancient mitochondrial replacement between currently isolated D. groenlandicus and D. hudsonius. The nuclear genome phylogeny reveals species cladogenesis and supports the hypothesis that D. hudsonius with primitive and distinct molar morphology represents a relic of the first migration event from Eurasia to North America. Species widely distributed in the North American Arctic, D. groenlandicus, with advanced dental morphology originated from a later colonization event across the Bering Land Bridge. This study shows ancient mitochondrial capture between two Arctic species and emphasizes the importance of multilocus approaches for phylogenetic inference.

Beringia and the Settlement of the Western Hemisphere

Previously, we addressed the problem of what variable(s) limited widespread human settlement of the Americas before ~15 ka. We concluded that while non-modern human taxa (e. g., Neanderthals) probably did not inhabit high-latitude environments (due to cold climate and/ or low plant and animal productivity) and thus could not disperse in the Western Hemispherevia Beringia, modern humans likely were denied access to mid-latitude North America >15 ka by coastal and interior ice sheets. Here we reexamine the problem with respect to modern humans in light of a revised chronology for glaciers and sea level, new research in paleo-genomics, and some new archaeological discoveries. During 35–30 ka, a lineage with west Eurasian roots occupied the Great Arctic Plain and may have expanded into eastern arctic Beringia and mid-latitude North America via an ice-free corridor. An East Asian lineage associated with microblade technology occupied the Lena Basin during the LGM and expanded onto the Great Arctic Plain >15 ka, possibly as early as the GI 2 interstadial (24–23 ka). Their immediate descendants probably occupied the southern Bering Land Bridge and Northwest Pacific coast >15 ka and dispersed widely in the Western Hemisphere during GI 1 (14.5–12.9 ka), primarily if not exclusively via a coastal route. The coalesced Laurentide and Cordilleran ice sheets blocked interior access to mid-latitude America until 13.8 ± 0.5 ka (and possibly later due to the length and narrow width of the ice-free corridor >13 ka).

Phylogenetic Relationships, Speciation, and Origin of Armillaria in the Northern Hemisphere: A Lesson Based on rRNA and Elongation Factor 1-Alpha.

Armillaria species have a global distribution and play various roles in the natural ecosystems, e.g., pathogens, decomposers, and mycorrhizal associates. However, their taxonomic boundaries, speciation processes, and origin are poorly understood. Here, we used a phylogenetic approach with 358 samplings from Europe, East Asia, and North America to delimit the species boundaries and to discern the evolutionary forces underpinning divergence and evolution. Three species delimitation methods indicated multiple unrecognized phylogenetic species, and biological species recognition did not reflect the natural evolutionary relationships within Armillaria; for instance, biological species of A. mellea and D. tabescens are divergent and cryptic species/lineages exist associated with their geographic distributions in Europe, North America, and East Asia. While the species-rich and divergent Gallica superclade might represent three phylogenetic species (PS I, PS II, and A. nabsnona) that undergo speciation. The PS II contained four lineages with cryptic diversity associated with the geographic distribution. The genus Armillaria likely originated from East Asia around 21.8 Mya in early Miocene when Boreotropical flora (56–33.9 Mya) and the Bering land bridge might have facilitated transcontinental dispersal of Armillaria species. The Gallica superclade arose at 9.1 Mya and the concurrent vicariance events of Bering Strait opening and the uplift of the northern Tibetan plateau might be important factors in driving the lineage divergence.

Phylogeography and Re-Evaluation of Evolutionary Rate of Powassan Virus Using Complete Genome Data.

Simple SummaryThe evolution of human pathogenic viruses is one of the pressing problems of modern biology and directly relevant to public health. Many important aspects of virus evolution (e.g., evolutionary rate, population size, and migration history) are ‘hidden’ from the naked eye of a researcher. Modern bioinformatics methods make it possible to evaluate and visualize such evolutionary particularities of viruses. In this paper, we reconstructed the migration history and estimated the evolutionary rate of one of the most dangerous neuroinvasive and neurotropic tick-borne flaviviruses—Powassan virus (POWV)—distributed in North America and the Far East of Russia. Using the dates obtained, we hypothesized that the divergence of the most recent common ancestor of POWV into two independent genetic lineages most likely occurred because of the melting of glaciers that began at 11.72 Kya in the Holocene due to the climate warming-caused flooding of the isthmus between Eurasia and North America.In this paper, we revealed the genetic structure and migration history of the Powassan virus (POWV) reconstructed based on 25 complete genomes available in NCBI and ViPR databases (accessed in June 2021). The usage of this data set allowed us to perform a more precise assessment of the evolutionary rate of this virus. In addition, we proposed a simple Bayesian technique for the evaluation and visualization of ‘temporal signal dynamics’ along the phylogenetic tree. We showed that the evolutionary rate value of POWV is 3.3 × 10−5 nucleotide substitution per site per year (95% HPD, 2.0 × 10−5–4.7 × 10−5), which is lower than values reported in the previous studies. Divergence of the most recent common ancestor (MRCA) of POWV into two independent genetic lineages most likely occurred in the period between 2600 and 6030 years ago. We assume that the divergence of the virus lineages happened due to the melting of glaciers about 12,000 years ago, which led to the disappearance of the Bering Land Bridge between Eurasia and North America (the modern Alaskan territory) and spatial division of the viral areal into two parts. Genomic data provide evidence of the virus migrations between two continents. The mean migration rate detected from the Far East of Russia to North America was one event per 1750 years. The migration to the opposite direction occurred approximately once per 475 years.

Phylogeography of Artemisia frigida (Anthemideae, Asteraceae) based on genotyping-by-sequencing and plastid DNA data: Migration through Beringia.

Artemisia frigida is a temperate grassland species that has the largest natural range among its genus, with occurrences across the temperate grassland biomes of Eurasia and North America. Despite its wide geographic range, we know little about the species' distribution history. Hence, we conducted a phylogeographical study to test the hypothesis that the species' distribution pattern is related to a potential historical migration over the 'Bering land bridge'. We applied two molecular approaches: genotyping-by-sequencing (GBS) and Sanger sequencing of the plastid intergenic spacer region (rpl32 - trnL) to investigate genetic differentiation and relatedness among 21 populations from North America, Middle Asia, Central Asia and the Russian Far East. Furthermore, we identified the ploidy level of individuals based on GBS data. Our results indicate that A.frigida originated in Asia, spread northwards to the Far East and then to North America across the Bering Strait. We found a pronounced genetic structuring between Middle and Central Asian populations with mixed ploidy levels, tetraploids in the Far East, and nearly exclusively diploids in North America except for one individual. According to phylogenetic analysis, two populations of Kazakhstan (KZ2 and KZ3) represent the most likely ancestral diploids that constitute the basally branching lineages, and subsequent polyploidization has occurred on several occasions independently. Mantel tests revealed weak correlations between genetic distance and geographical distance and climatic conditions, which indicates that paleoclimatic fluctuations may have more profoundly influenced A.frigida's spatial genetic structure and distribution than the current environment.

Lions and brown bears colonized North America in multiple synchronous waves of dispersal across the Bering Land Bridge.

The Bering Land Bridge connecting North America and Eurasia was periodically exposed and inundated by oscillating sea levels during the Pleistocene glacial cycles. This land connection allowed the intermittent dispersal of animals, including humans, between Western Beringia (far northeast Asia) and Eastern Beringia (northwest North America), changing the faunal community composition of both continents. The Pleistocene glacial cycles also had profound impacts on temperature, precipitation and vegetation, impacting faunal community structure and demography. While these palaeoenvironmental impacts have been studied in many large herbivores from Beringia (e.g., bison, mammoths, horses), the Pleistocene population dynamics of the diverse guild of carnivorans present in the region are less well understood, due to their lower abundances. In this study, we analyse mitochondrial genome data from ancient brown bears (Ursus arctos; n=103) and lions (Panthera spp.; n=39), two megafaunal carnivorans that dispersed into North America during the Pleistocene. Our results reveal striking synchronicity in the population dynamics of Beringian lions and brown bears, with multiple waves of dispersal across the Bering Land Bridge coinciding with glacial periods of low sea levels, as well as synchronous local extinctions in Eastern Beringia during Marine Isotope Stage 3. The evolutionary histories of these two taxa underline the crucial biogeographical role of the Bering Land Bridge in the distribution, turnover and maintenance of megafaunal populations in North America.

Phylogenomics and biogeography of Catalpa (Bignoniaceae) reveal incomplete lineage sorting and three dispersal events

Catalpa Scop. (Bignoniaceae) is a small genus (8 spp.) of trees that is disjunctly distributed among eastern Asia, eastern United States, and the West Indies. Catalpa bears beautiful inflorescences and have been cultivated as important ornamental trees for landscaping, gardening, and timber. However, the phylogenetic relationships and biogeographic history of the genus have remained unresolved. In this study, we used a large genomic dataset that includes data from the chloroplast (plastomes), and nuclear genomes (ITS and 5,759 single-copy nuclear genes) to reconstruct phylogenetic relationship within Catalpa, test interspecific gene flow events within the genus, and infer its biogeographic history. Our phylogenetic results indicate that Catalpa is monophyletic containing two main clades, section Catalpa and section Macrocatalpa. Section Catalpa is further divided into three subclades. While most relationships are congruent between the chloroplast and nuclear datasets, the position of C. ovata differs, likely due to incomplete lineage sorting. Interspecific gene flow events include C. bungei s.s. with vectors of inheritance from C. duclouxii and C. fargesii, supporting a combination of these three species and recognizing a broadly circumscribed C. bungei s.l. Our biogeographic study suggests three main dispersal events, two of which occurred during the Oligocene. The first dispersal event occurred from southwestern North America and Mexico into the Greater Antilles giving rise to the ancestor of the section of Macrocatalpa. The second dispersal event also occurred from southwestern North America and Mexico, but led to central and northern North America, subsequently reaching China through the Bering land bridge, and also reaching Europe through the North Atlantic land bridge. The third dispersal event took place in the Miocene from China to North America and gave rise to a clade composed of C. bignonioides and C. speciosa. This study uses a phylogenomic approach and biogeographical methods to infer the evolutionary history of Catalpa, highlighting issues associated with gene tree discordance, and suggesting that incomplete lineage sorting likely played an important role in the evolutionary history of Catalpa.

Niche evolution and historical biogeography of lady slipper orchids in North America and Eurasia

AbstractAimDispersal and subsequent adaptation to local environmental and climatic conditions play major roles in the evolution and current‐day distribution of plants and animals, but their relative importance is not always easy to disentangle. The aim of this study was to provide a comprehensive phylogenetic analysis of the terrestrial orchid genus Cypripedium to better understand the role of niche evolution and historical dispersal events in driving the radiation of the genus in North America and Eurasia.LocationNorthern Hemisphere.TaxonCypripedium (Orchidaceae).MethodsWe used a relaxed molecular clock analysis to infer phylogenetic relationships among 45 Cypripedium species and to estimate divergence times. Niche modelling was used to assess the potential distribution of each species in both continents, whereas ancestral area reconstructions using BioGeoBEARS were used to estimate changes in historical biogeography. Subsequently, the ancestral state of niche conditions was assessed for each species using maximum likelihood methods and we tested for phylogenetic signal in the evolution of niche conditions using Blomberg's K and Pagel's λ. A mantel test was used to test for a correlation between phylogenetic distances and niche overlap in Cypripedium.ResultsWe found that Cypripedium originated in Central America and underwent multiple dispersal events between North America and Eurasia after long‐distance seed dispersal or dispersal via the Bering land bridge. The mountainous area of Southwest China provided refuge areas for Cypripedium orchids during episodes of increased glaciation. Our results further showed that Cypripedium has gradually increased its tolerance to seasonal temperature changes, providing evidence for significant niche evolution through time. No significant correlation between current niches and phylogenetic relatedness was observed.Main conclusionsOur study provides clear evidence that repeated dispersal and adaptation to increased cooling after the Eocene−Oligocene Transition has contributed to the radiation of Cypripedium in the Northern Hemisphere.

Phylogenomic framework of the IRLC legumes (Leguminosae subfamily Papilionoideae) and intercontinental biogeography of tribe Wisterieae

The inverted repeat-lacking clade (IRLC) is one of the most derived clades within the subfamily Papilionoideae of the legume family, and includes various economically important plants, e.g., chickpeas, peas, liquorice, and the largest genus of angiosperms, Astragalus. Tribe Wisterieae is one of the earliest diverged groups of the IRLC, and its generic delimitation and spatiotemporal diversification needs further clarifications. Based on genome skimming data, we herein reconstruct the phylogenomic framework of the IRLC, and infer the inter-generic relationships and historical biogeography of Wisterieae. We redefine tribe Caraganeae to contain Caragana only, and tribe Astragaleae is reduced to the Erophaca-Astragalean clade. The chloroplast capture scenario was hypothesized as the most plausible explanation of the topological incongruences between the chloroplast CDSs and nuclear ribosomal DNA trees in both the Glycyrrhizinae-Adinobotrys-Wisterieae clade and the Chesneyeae-Caraganeae-Hedysareae clade. A new name, Caragana lidou L. Duan & Z.Y. Chang, is proposed within Caraganeae. Thirteen genera are herein supported within Wisterieae, including a new genus, Villosocallerya L. Duan, J. Compton & Schrire, segregated from Callerya. Our biogeographic analyses suggest that Wisterieae originated in the late Eocene and its most recent common ancestor (MRCA) was distributed in continental southeastern Asia. Lineages of Wisterieae remained in the ancestral area from the early Oligocene to the early Miocene. By the middle Miocene, Whitfordiodendron and the MRCA of Callerya-Kanburia-Villosocallerya Clade became disjunct between the Sunda area and continental southeastern Asia, respectively; the MRCA of Wisteria migrated to North America via the Bering land bridge. The ancestor of Austrocallerya and Padbruggea migrated to the Wallacea-Oceania area, which split in the early Pliocene. In the Pleistocene, Wisteria brachybotrys, W. floribunda and Wisteriopsis japonica reached Japan, and Callerya cinerea dispersed to South Asia. This study provides a solid phylogenomic for further evolutionary/biogeographic/systematic investigations on the ecologically diverse and economically important IRLC legumes.

Ancient horse genomes reveal the timing and extent of dispersals across the Bering Land Bridge.

The Bering Land Bridge (BLB) last connected Eurasia and North America during the Late Pleistocene. Although the BLB would have enabled transfers of terrestrial biota in both directions, it also acted as an ecological filter whose permeability varied considerably over time. Here we explore the possible impacts of this ecological corridor on genetic diversity within, and connectivity among, populations of a once wide-ranging group, the caballine horses (Equus spp.). Using a panel of 187mitochondrial and eight nuclear genomes recovered from present-day and extinct caballine horses sampled across the Holarctic, we found that Eurasian horse populations initially diverged from those in North America, their ancestral continent, around 1.0-0.8million years ago. Subsequent to this split our mitochondrial DNA analysis identified two bidirectional long-range dispersals across the BLB ~875-625 and ~200-50 thousand years ago, during the Middle and Late Pleistocene. Whole genome analysis indicated low levels of gene flow between North American and Eurasian horse populations, which probably occurred as a result of these inferred dispersals. Nonetheless, mitochondrial and nuclear diversity of caballine horse populations retained strong phylogeographical structuring. Our results suggest that barriers to gene flow, currently unidentified but possibly related to habitat distribution across Beringia or ongoing evolutionary divergence, played an important role in shaping the early genetic history of caballine horses, including the ancestors of living horses within Equus ferus.

Phylogenomics and biogeography of Wisteria: Implications on plastome evolution among inverted repeat‐lacking clade (IRLC) legumes

AbstractThe genus Wisteria (Fabaceae) is disjunctly distributed in eastern Asian and eastern North American temperate deciduous forests, and it is widely cultivated around the world as spectacular garden plants. It is a member of inverted repeat‐lacking clade (IRLC). The IRLC Species are characterized by the loss of an IR region in their plastomes, which has long been of great interest. In this research, we report whole plastome sequences from all four Wisteria species and a Wisteriopsis japonica, combining these with existing data to explore phylogenetic relationships and biogeography of Wisteria, as well as plastome evolution of IRLC species. Phylogenetic analyses recognized a clade containing Glycyrrhiza–Wisteriopsis–Wisteria as sister to the remaining genera of IRLC. North American Wisteria frutescens and the three Asian species formed reciprocal clades, and Wisteria brachybotrys was sister to Wisteria floribunda and Wisteria sinensis. Wisteria may have originated in Japan near the boundary of the Oligocene and Miocene. The disappearance of Bering Land Bridge in the late Miocene might lead to the Eastern Asian–Eastern North American disjunction of Wisteria. Allopatric speciation of Wisteria between the Japanese archipelago and the Asian continent in the Quaternary increased the species richness of eastern Asia in comparison with eastern North America. Synonymous substitution rates (dS) of protein‐coding genes in the IRLC species were around 2‐fold (SC genes) or 11‐fold (IR genes) higher than those of non‐IRLC species. For both SC and IR genes, herbaceous legumes have around 3‐fold higher dS than woody ones. Both loss of one IR region and herbaceous habit elevated substitution rates of the plastomes.

Molecular phylogeny of Megasternini terrestrial water scavenger beetles (Hydrophilidae) reveals repeated continental interchange during Paleocene‐Eocene thermal maximum

AbstractMegasternini is the largest group of terrestrial water scavenger beetles (Coleoptera: Hydrophilidae) represented by ca. 600 described species distributed worldwide. The highest species diversity is known from tropical areas of all continents. In this study, we used sequences of eight gene regions (five nuclear and three mitochondrial) to investigate the phylogenetic relationships and historical biogeography of this group, implementing maximum likelihood (ML) and Bayesian topology inference, Bayesian divergence dating, ML‐based ancestral area estimation and Bayesian diversification analyses. Topology analyses reveal two main lineages of Megasternini characterized by the morphology of male genitalia and surrounding sclerites; these lineages are defined here as subtribes Megasternina Mulsant and Oosternina new subtribe. We identify 12 principal clades of Megasternini, three in Oosternina and nine in Megasternina. These clades group the taxa largely by their geographic distribution rather than morphology, indicating a parallel evolution of morphological characters. Genera Cercyon Leach, Oosternum Sharp, Cetiocyon Hansen, Australocyon Hansen and Pelosoma Mulsant were not recovered as monophyletic. Species of Cercyon, the most diverse genus in the tribe, are found in all principal clades in both subtribes. These results suggest a need for the reorganization of generic concepts in the tribe. The historical biogeography analysis reveals a series of parallel intercontinental dispersal events, including the colonization of South America by Australian members of Oosternina ca. 90 million years ago (mya) and at least five dispersal events between Asia and America ca. 63–55 mya via the Beringia land bridge. The timing of the Asia‐America faunal interchange corresponds to the hyperthermal climate of the Late Paleocene and Early Eocene that allowed the expansion of tropical and subtropical biomes towards polar regions. Diversification analyses revealed no effect of intercontinental dispersals on speciation or extinction rates and suggested a possible effect of declining global temperatures in the last 20 million years.

Awards of JSE Outstanding Papers (2019)

Awards of JSE Outstanding Papers (2019)

Around the world in 10 million years: Rapid dispersal of a kleptoparasitoid spider wasp (Pompilidae: Ceropales)

ABSTRACTAimCosmopolitan distributions have classically been explained by Pangaean vicariance. However, evidence of recently diverged cosmopolitan groups has re‐opened consideration on the processes involved. Our aim is to estimate the processes leading to the worldwide distribution of the kleptoparasitoid genus Ceropales.LocationWorldwide.TaxonCeropales spider wasps (Pompilidae).MethodsData from three molecular markers for 52 specimens of Ceropales and two calibration points from previous analyses were used to reconstruct a dated phylogeny under a relaxed molecular clock. We compared the fit of 12 models using BioGeoBEARS: DEC (subset sympatry, narrow vicariance), DIVALIKE (narrow and wide vicariance), BAYAREALIKE (widespread sympatry), and these same models with an added jump dispersal parameter and constraining dispersal rates among areas. Using the AIC best‐fit model (DEC+J), we performed Biogeographic Stochastic Mapping (BSM) to infer biogeographic processes by simulating 200 BSM on the BEAST chronogram.ResultsThe origin of crown‐group Ceropales was ca. 10.6 Ma (15.7–6.5 95% HPD), and 11 jump‐dispersal events explain its distribution. A constrained DEC+J model, allowing adjacent area dispersal was the best‐fit AIC model. Dispersals across the Bering land bridge, Isthmus of Panama, Mediterranean Sea, and Sunda Plains took place from the late Miocene to present times.Main conclusionsCeropales is a recently diverged group that originated in Eurasia in the Miocene and dispersed to occupy the Americas, Africa, and Australia. Colonization was probably favored by the already diversified hosts (Pompilinae and Pepsinae), which reduced limiting factors such as food resource and nest construction. The evolution of a generalist parasitic lifestyle could facilitate long‐distance dispersal. This is the first study addressing the global historical biogeography of a cosmopolitan spider wasp.

Ultraconserved element phylogenomics and biogeography of the agriculturally important mason bee subgenus Osmia (Osmia)

AbstractOne of the most important non‐Apis groups of bees for agriculture is the mason bee subgenus Osmia Panzer (Osmia), or Osmia s.s. (Hymenoptera: Megachilidae). Out of the 29 known species, four have been developed as managed pollinators of orchards. In addition, the group is important as a source of non‐native pollinators, given that several species have been introduced into new areas. Osmia s.s. occurs naturally throughout the northern temperate zone with greatest species richness in Europe and Asia. Here, we integrate phylogenomic data from ultraconserved elements (UCEs), near complete taxon sampling, and a diversity of analytical approaches to infer the phylogeny, divergence times and biogeographic history of Osmia s.s. We also demonstrate how mitochondrial sequence data can be extracted from ultraconserved element data and combined with sequences from public repositories in order to test the phylogeny, examine species boundaries and identify specimen‐associated, non‐bee DNA. We resolve the phylogeny of Osmia s.s. and show strong support that Nearctic Osmia ribifloris is the sister group to the rest of the subgenus. Biogeographic analyses indicate that the group originated during the Late Miocene in the West Nearctic plus East Palearctic region following dispersal from the East Palearctic to the West Nearctic across the Bering land bridge prior to its closure 5.5–4.8 Ma. The mitochondrial DNA results reveal potential taxonomic synonymies involving Osmia yanbianensis and Osmia opima, and Osmia rufina, Osmia rufinoides and Osmia taurus.

Fossil fruits of Firmiana and Tilia from the middle Miocene of South Korea and the efficacy of the Bering land bridge for the migration of mesothermal plants

Determining whether the high-latitude Bering land bridge (BLB) was ecologically suitable for the migration of mesothermal plants is significant for Holarctic phytogeographic inferences. Paleobotanical studies provide a critical source of data on the latitudinal positions of different plant lineages at different times, permitting assessment of the efficacy of the BLB for migration. Here we report exceptionally preserved fossils of Firmiana and Tilia endochrysea from the middle Miocene of South Korea. This represents a new reliable record of Firmiana and the first discovery of the T. endochrysea lineage in the fossil record of Asia. The occurrence of these fossils in South Korea indicates that the two lineages had a distribution that extended much farther north during the middle Miocene, but they were still geographically remote from the BLB. In light of the broader fossil record of Asia, our study shows that, in the middle Miocene, some mesothermal plants apparently inhabited the territory adjacent to the BLB and thus they were possibly capable of utilizing the BLB as a migratory corridor. Some other mesothermal plants, such as Firmiana and the T. endochrysea lineages, however, are restricted to more southern regions relative to the BLB based on current fossil evidence. These lineages may have been ecologically unable to traverse the BLB, which raises questions about the efficacy of the BLB as a universal exchange route for mesothermal plants between Asia and North America during the middle Miocene.

Phylotranscriptomics reveals the complex evolutionary and biogeographic history of the genus Tsuga with an East Asian-North American disjunct distribution

The disjunct distribution between East Asia and North America is one of the best established biogeographic patterns. A robust phylogeny is fundamental for understanding the biogeographic histories of taxa with this distribution pattern. Tsuga (hemlock) is a genus of Pinaceae with a typical intercontinental disjunct distribution in East Asia and eastern and western North America, and its phylogeny has not been completely reconstructed in previous studies. In this study, we reconstructed a highly resolved phylogeny of Tsuga using 881 nuclear genes, 60 chloroplast genes and 23 mitochondrial genes and explored its biogeographic and reticulate evolutionary history. The results of phylogenetic analysis, molecular dating and ancestral area reconstruction indicate that Tsuga very likely originated from North America in the late Oligocene and dispersed from America to East Asia via the Bering Land Bridge during the middle Miocene. In particular, we found complex reticulate evolutionary pattern among the East Asian hemlock species. T. sieboldii possibly originated from hybridization with the ancestor of T. chinensis from mainland China and T. forrestii as the paternal donor and the ancestor of T. diversifolia and T. ulleungensis as the maternal donor. T. chinensis (Taiwan) could have originated by hybridization together with T. sieboldii and then evolved independently after dispersal to the Taiwan Island, subsequently experiencing mitochondrial DNA introgression with T. chinensis from mainland China. Moreover, our study found that T. chinensis from western China is more closely related to T. forrestii than to T. chinensis from eastern China. The nonmonophyletic T. chinensis needs taxonomic reconsideration.

Historical biogeography of Acer L. (Sapindaceae): genetic evidence for Out-of-Asia hypothesis with multiple dispersals to North America and Europe

Biogeography is the study of where, when, and how modern species evolved and diversified. Acer L. (maple) is one of the most diverse and widespread genera in the Northern Hemisphere. It comprises 124–156 species in the world, approximately 80% species of Acer are native in Asia. The current diversity center of Acer is not congruent with the distribution of the oldest fossils of the genus. Therefore, we herein used 84 species and subspecies to reconstruct the phylogeny and investigate the biogeographic history of Acer using nuclear ITS and three cpDNA fragments (psbA-trnH spacer, rpl16 intron, and trnL-trnF spacer) with maximum likelihood, maximum parsimony, and Bayesian inference methods. The analyses showed that the current diversity center and the origin center of Acer is Asia. Additionally, the North American and Euro-Mediterranean species originated from multiple sources from Asia via the North Atlantic Land Bridge and the Bering Land Bridge, and intercontinental migration has mainly occurred since the Miocene. This study not only provides a novel insight of the origin and dispersal routes of Acer but also exemplifies how past climatic changes affect the diversification-rates of Northern Hemisphere forest trees.