Beringia Research Articles

Holarctic genetic structure and range dynamics in the woolly mammoth

Ancient DNA analyses have provided enhanced resolution of population histories in many Pleistocene taxa. However, most studies are spatially restricted, making inference of species-level biogeographic histories difficult. Here, we analyse mitochondrial DNA (mtDNA) variation in the woolly mammoth from across its Holarctic range to reconstruct its history over the last 200 thousand years (kyr). We identify a previously undocumented major mtDNA lineage in Europe, which was replaced by another major mtDNA lineage 32–34 kyr before present (BP). Coalescent simulations provide support for demographic expansions at approximately 121 kyr BP, suggesting that the previous interglacial was an important driver for demography and intraspecific genetic divergence. Furthermore, our results suggest an expansion into Eurasia from America around 66 kyr BP, coinciding with the first exposure of the Bering Land Bridge during the Late Pleistocene. Bayesian inference indicates Late Pleistocene demographic stability until 20–15 kyr BP, when a severe population size decline occurred.

Miocene–Pliocene speciation, introgression, and migration of Patis and Ptilagrostis (Poaceae: Stipeae)

Genetic interchange between American and Eurasian species is fundamental to our understanding of the biogeographical patterns, and we make a first attempt to reconstruct the evolutionary events in East Asia that lead to the origin and dispersal of two genera, Patis and Ptilagrostis. We conducted a molecular phylogenetic study of 78 species in the tribe Stipeae using four plastid DNA sequences (ndhF, rpl32-trnL, rps16-trnK, and rps16 intron) and two nuclear DNA sequences (ITS and At103). We use single copy nDNA gene At103 for the first time in the grasses to elucidate the evolutionary history among members of the Stipeae. Ampelodesmos, Hesperostipa, Oryzopsis, Pappostipa, Patis, and Stipa are found to be of multiple origins. Our phylograms reveal conflicting positions for Ptilagrostis alpina and Pt. porteri that form a clade with Patis coreana, P. obtusa, and P. racemosa in the combined plastid tree but are aligned with other members of Ptilagrostis in the ITS tree. We hypothesize that Ptilagrostis still retains the nucleotype of an extinct genus which transited the Bering land bridge from American origins in the late Miocene (minimum 7.35–6.37mya) followed by hybridization and two plastid capture events with a Trikeraia-like taxon (7.96mya) and para-Patis (between 5.32 and 3.76mya). Ptilagrostis porteri and Patis racemosa then migrated to continental North America 1.7–2.9mya and 4.3–5.3mya, respectively.

A new species of the bristletail genus Pedetontus silv. (Thysanura, Machilidae) from Thailand

A new bristletail species, Pedetontus phuketi sp. n., is described from Phuket Island, Thailand. It is most similar to P. hainanensis Yu, Zhang W.-W. et Zhang J.-Y., 2010 described from Hainan Island (China). The genus Pedetontus comprises 33 described species in two subgenera: Pedetontus s. str. (6 species) and Verhoeffilis (27 species). The subgenus Verhoeffilis has originated in the southeastern part of the Palaearctic Region. Its representatives migrated to North America in the Paleocene through the Bering Land Bridge which was sunken in the Eocene, so that the Nearctic centre of Pedetontus speciation became isolated and the subgenus Pedetontus s. str. has been formed. The Bering Land Bridge was formed at the end of the Miocene, and the backward migration of bristletails of the subgenus Pedetontus s. str. from the Nearctic to the Palaearctic occurred. Pedetontus palaearcticus was formed on Kamchatka. The southward migration of bristletails of the subgenus Verhoeffilis has led to formation of 10 Indo-Malayan species.

Seeds ofWeigela(Caprifoliaceae) from the Early Miocene of Weichang, China and the biogeographical history of the genus

AbstractSeeds of the genusWeigela(Caprifoliaceae) are described from the Early Miocene Hannuoba Formation of Weichang County, Hebei Province, China. They are flat, elliptic, with translucent membranous wings on three sides. Comparison with extant and fossil species ofWeigelaindicates that these seeds are different which therefore were assigned to a new species,Weigela weichangensis. On the basis of the fossil record, the distribution ofWeigelathrough geologic ages is shown on a series of palaeogeographic maps of the Northern Hemisphere. The oldest fossils ofWeigelaare seeds from the Oligocene of West Siberia, Asia. The genus later expanded into East Asia and Europe as well as into Arctic/Subarctic areas of North America via the North Atlantic Land Bridge and/or Bering Land Bridge in the Miocene.Weigeladisappeared from Europe and North America probably during the Pleistocene glaciations, but survived in Asia until now.

Present trans‐Pacific disjunct distribution of Aristolochia subgenus Isotrema (Aristolochiaceae) was shaped by dispersal, vicariance and extinction

AbstractAimIsotrema is a monophyletic subgenus of Aristolochia with species in East Asia and North/Central America. Earlier studies, based on limited sampling, suggested that the Asian and American species do not form two reciprocal sister clades. We reconstructed phylogenetic relationships within Isotrema to infer the biogeographical events that have shaped its present‐day distribution.LocationEastern Asia, North America, Mexico, Central America.MethodsWe performed parsimony and Bayesian phylogenetic analyses of 54 accessions using three chloroplast regions. The temporal origins were traced with relaxed phylogenetics and penalized likelihood using fossil calibrations; these methods were combined with ancestral area reconstructions in a comparative approach using statistical dispersal–vicariance analysis (S‐DIVA) and dispersal–extinction–cladogenesis (DEC) analyses.ResultsThe ancestors of the herbaceous eastern North American species and the woody species probably diverged during the Oligocene. The woody species form a Neotropical and a North American/Eastern Asian clade. Diversification in the Neotropical and North American/Eastern Asian clades occurred mostly in the Miocene. In the latter clade, two further intercontinental splits are reconstructed: between the exclusively western North American Aristolochia californica and most of the Asian taxa, and between A. manshuriensis and A. tomentosa.Main conclusionsThe present distribution of Isotrema developed via a number of dispersal, vicariance and extinction events. The disjunct distributions observed may be the result mainly of non‐synchronous events (e.g. a decrease of mean annual temperature in the Oligocene and the development of unfavourable conditions across the Bering land bridge) that were responsible for the fragmentation of the mesophytic forests. Later diversifications may be correlated with events such as the orogeny of the Western Cordillera and Appalachian Mountains, the development of extensive grasslands in North America, and the mainland extension of Central America southwards to western and central Panama.

Historical biogeography of Eastern Asian–Eastern North American disjunct Melaphidina aphids (Hemiptera: Aphididae: Eriosomatinae) on Rhus hosts (Anacardiaceae)

Intercontinental biotic disjunctions have been documented and analyzed in numerous Holarctic taxa. Patterns previously synthesized for animals compared to plants suggest that the timing of animal disjunctions are mostly Early Tertiary and were generated by migration and vicariance events occurring in the North Atlantic, while plant disjunctions are mostly Mid-Late Tertiary and imply migration and vicariance over Beringia. Melaphidina aphids (Hemiptera: Aphididae: Fordini) exhibit host-alternating life cycles comprising an obligate seasonal shift between Rhus subgenus Rhus species (Anacardiaceae) and mosses (Bryophyta). Similar to their Rhus hosts, melaphidines are distributed disjunctly between Eastern Asia and Eastern North America. We examined evolutionary relationships within Melaphidina to determine the position of the North American lineage, date its divergence from Asian relatives, and compare these results to a previous historical biogeographic study of Rhus. We sampled nine species and three subspecies representing all six genera of Melaphidina. Data included sequences of mitochondrial cytochrome c oxidase subunits I and II+leucine tRNA, cytochrome b, and nuclear elongation factor 1α genes. Phylogenetic analyses (Bayesian, maximum-likelihood, parsimony) of the combined data (3282bp) supported the monophyly of all genera except Nurudea and Schlechtendalia, due to the position of N. ibofushi. While the exact position of the North American Melaphis was not well resolved, there was high support for a derived position within Asian taxa. The divergence of Melaphis from Asian relatives centered on the Eocene–Oligocene boundary (∼33–35Ma), which coincides with closure of Beringian Land Bridge I. This also corresponded to the Asian–North American disjunction previously estimated for subgenus Rhus spp. We suggest the late-Eocene Bering Land Bridge as the most likely migration route for Melaphis ancestors, as was also hypothesized for North American Rhus ancestors. Results for the Melaphidina disjunction depart from the modal pattern in animal lineages, and present a case where insect and host-plant taxa apparently responded similarly to Tertiary climate change.

Serpentine Hot Springs, Alaska: results of excavations and implications for the age and significance of northern fluted points

The dispersal of Homo sapiens across the New World is one of the greatest chapters in the history of our species; however, major questions about this late Pleistocene diaspora remain unanswered. Two contentious issues are the timing of colonization of the Bering Land Bridge and origin of Clovis, which at 13,000 calendar years ago is the earliest unequivocal complex of archaeological sites in temperate North America, known by its specialized fluted spear points. One hypothesis is that fluting technology emerged in Beringia and from there was carried southbound, with fluted points becoming the diagnostic “calling card” of early Paleoindians spreading across the Western Hemisphere. Fluted points have long been known from Alaska, yet until now they have never been found in a datable geologic context, making their relationship to Clovis a mystery. Here we show that a new archaeological site at Serpentine Hot Springs, Bering Land Bridge National Preserve, Alaska, contains fluted points in a stratified geologic deposit dating to no earlier than 12,400 calendar years ago. Our results suggest that Alaska's fluted-point complex is too young to be ancestral to Clovis, and that it instead represents either a south-to-north dispersal of early Americans or transmission of fluting technology from temperate North America. These results suggest that the peopling of the Americas and development of Paleoindian technology were much more complex than traditional models predict.

A New Material of Lindera (Lauraceae) of the Late Pliocene from Tengchong, Yunnan and the Genus' Biogeography Significance

Abstract:Lindera is a large genus of graceful, pleasantly scented and common native trees and shrubs of southern China and neighboring regions of SE Asia. There is a well‐documented Cenozoic fossil record not only in these regions but also from elsewhere. A new fossil leaf record has been found in diatomite beds from the Upper Pliocene Mangbang Formation of Tuantian, Tengchong County, Yunnan. The leaves are identified and assigned to Lindera acuminatissima K. Q. Dao et B. N. Sun sp. nov., by comparing their leaf architecture and epidermal characteristics with those of 51 extant Lauraceae species and with 15 known fossil Lindera taxa. The specimens have well‐preserved cuticles, with typical leaf architecture and epidermal characteristics of the Lauraceae, including entire leaf margin, intramarginal veins, basal ternate acrodromous primary veins, one‐cell trichome base, paracytic stomatal apparatus, sunken guard cells, subsidiary hardly staining cells and presence of oil cells. These characteristics are consistent with Lindera sect. Daphnidium but are different from reported fossil and extant species of Lindera. The cuticles of Lindera are fragile and delicate with only three Lindera fossils reported based on this tissue. In terms of paleobiogeography, the fossil record indicates that Lindera is distributed in high‐ to mid‐latitude regions of the Late Cretaceous to Paleocene northern hemisphere. Coincidentally, the records of Lindera located on both sides of the Bering Land Bridge possibly support the hypothesis that ancient plants extended via transcontinental exchanges through the Bering Corridor. In the Eocene, ancient Lindera spread to Europe through the Northern Degeer Route and the Southern Thulian Route. At the same time, ancient Lindera spread into Central Asia. Climatic changes and tectonization since the Neogene prevented the propagation of Lindera throughout Asia, North America and Europe, and hence the distribution areas have just regressed to the low‐latitude regions in Asia and North America. From the Paleogene to the Neogene, Lindera has changed its distribution by surviving extreme climate changes. Quaternary glaciations ultimately led to Lindera becoming extinct in Europe. The new record from Tengchong, Yunnan, with its lower latitude located in tropical and subtropical regions, indicates that Lindera has lived in those regions since the late Pliocene.

Rheumatoid Arthritis in Minorities

Rheumatoid Arthritis in Minorities

The Heinrich and Dansgaard-Oeschger climatic events during Marine Isotopic Stage 3: Searching for appropriate times for human colonization of the Americas

Marine Isotope Stage 3 (MIS 3) was an interstadial stage, a relatively warm climatic period which developed roughly between 60 and 50 and 30 cal. ka BP. Several very cold periods, known as Heinrich (H) events, developed during MIS 3 as a result of partial collapse of the North American ice sheet margins, with formation of huge amounts of icebergs which, after melting in more temperate latitudes, would have inundated the North Atlantic Ocean with low salinity waters which would have impeded the reach of the Gulf Stream into the North Atlantic Ocean. Several paleoclimatic moments with relatively warmer conditions, known as the Dansgaard-Oeschger (D-O) events, took place in between the Heinrich (H) events, throughout MIS 3. These H and D-O cycles would have been very short (perhaps even only around 1 ky each in some cases) and intense, with mean annual temperatures in the area of Beringia ca. 5–8 C° higher than those active at the Last Glacial Maximum (LGM; ca. 24 cal. ka B.P.) and perhaps close to those occurring in past interglacial periods, respectively. Even though climate was warmer, total melting of the continental ice sheets did not take place; thus, global sea level was perhaps still low enough to allow the persistence of the Beringia land bridge between Siberia and North America, without any interruptions throughout the entire MIS 3. The aims of this paper are to present paleoclimatic and paleogeographic information about MIS 3 and to discuss the most favorable chronology for human displacement through Beringia. At the times of MIS 3, there would have been no coalescence between the Laurentide and Cordilleran ice sheets; thus, both the hinterland path from Beringia southwards and the coastal route would have been open and enjoying moderate climate ecosystems, and thus available for humans. In this case, it is now possible to suggest possible moments for human penetration in North America, sometime between ca. 60–50 to 28 cal. ka B.P, during one or more D-O events (most likely sometime between the D-O 16 and D-O 3 events) throughout MIS 3. Other routes of human colonization of the Americas following other routes rather than that of Siberia-Beringia, if they ever existed, are not discussed in this paper.

Phylogenetics and biogeography of Theaceae based on sequences of plastid genes

AbstractDespite several morphological and molecular analyses of Theaceae, several outstanding issues remain in the phylogenetics and biogeography of the family including the disputed relationships among the tribes Gordonieae, Stewartieae, and Theeae, the controversial taxonomic status of Hartia and Stewartia, and the unclear biogeographic history of Gordonieae and Stewartieae. In this study we gathered DNA sequences of multiple plastid genes from 27 species of Theaceae representing all genera except Laplacea, conducted phylogenetic analyses using parsimony, likelihood, and Bayesian methods, and estimated divergence times within a Bayesian framework with fossil calibrations and molecular data. Our data provided further support for the three tribes in the family and for the sister‐group relationship of Theeae to Stewartieae plus Gordonieae. Within Gordonieae, our study for the first time offered strong molecular support for the sister relationship of Franklinia and Schima. Within Stewartieae, our data supported the paraphyly of Stewartia including Hartia. Within Stewartia, our data for the first time suggested that North American (NA) species Stewartia ovata was more closely related to eastern Asian (EA) species than to the other NA species Stewartia malacodendron. Biogeographic analyses indicated that disjunct endemic species of Gordonieae might have originated from NA and those of Stewartieae from EA. Divergence times of the EA‐NA disjunct pairs identified in this study (Franklinia and Schima in Gordonieae and S. ovata (NA) and Asian species of Stewartia) were estimated to be in the Mid‐Miocene. Population exchanges in Gordonieae and Stewartieae may have occurred over the Bering land bridge prior to the Mid‐Miocene.

Detection of Ancestry Informative HLA Alleles Confirms the Admixed Origins of Japanese Population

The polymorphisms in the human leukocyte antigen (HLA) region are powerful tool for studying human evolutionary processes. We investigated genetic structure of Japanese by using five-locus HLA genotypes (HLA-A, -B, -C, -DRB1, and -DPB1) of 2,005 individuals from 10 regions of Japan. We found a significant level of population substructure in Japanese; particularly the differentiation between Okinawa Island and mainland Japanese. By using a plot of the principal component scores, we identified ancestry informative alleles associated with the underlying population substructure. We examined extent of linkage disequilibrium (LD) between pairs of HLA alleles on the haplotypes that were differentiated among regions. The LDs were strong and weak for pairs of HLA alleles characterized by low and high frequencies in Okinawa Island, respectively. The five-locus haplotypes whose alleles exhibit strong LD were unique to Japanese and South Korean, suggesting that these haplotypes had been recently derived from the Korean Peninsula. The alleles characterized by high frequency in Japanese compared to South Korean formed segmented three-locus haplotype that was commonly found in Aleuts, Eskimos, and North- and Meso-Americans but not observed in Korean and Chinese. The serologically equivalent haplotype was found in Orchid Island in Taiwan, Mongol, Siberia, and Arctic regions. It suggests that early Japanese who existed prior to the migration wave from the Korean Peninsula shared ancestry with northern Asian who moved to the New World via the Bering Strait land bridge. These results may support the admixture model for peopling of Japanese Archipelago.

Late Quaternary lake records from the Anadyr Lowland, Central Chukotka (Russia)

Three lake cores provide insight into the vegetation and climate history of the past ∼45,000 14C yr in the Anadyr Lowland, a key paleogeographic link between the Bering Land Bridge (BLB) and interior Western Beringia (WB). Although not without chronological issues, these records suggest that the Late Pleistocene interstade (approximating Oxygen Isotope Stage (OIS) 3) was a time of unstable environments consistent with previous interpretations for southern areas of WB and in contrast to more stable conditions inferred for northern WB. A hiatus in the records during OIS2 implies dry, frigid environments in the Anadyr Lowland. Previous research suggested that Chuktoka was a westward extension of relatively mesic environments of the BLB, which acted as a “filter” to intercontinental migrations. The Lowland data indicate that Chukotka may have been more of a transitional zone between mesic BLB and more xeric regions of western WB. A structurally novel biome dominated by deciduous forest and high-shrub tundra was proposed as occupying much of Beringia between ∼11,000 and 9000 14C yr BP. The unusual pollen assemblage that characterizes the Lowland suggests that perhaps a second biome was also present in Beringia, one that was dominated by meadows with Betula shrub thickets.

A Review of the Fossil Record of the Genus Itea (Iteaceae, Saxifragales) with Comments on its Historical Biogeography

Itea is a genus of about 20 species of trees and shrubs that are today native to southeastern North America, eastern Asia, and eastern Africa. In this paper, I review the fossil record of Itea, which is based on four types of fossils: diporate, psilate pollen attributed to Itea or the dispersed pollen genus Iteapollis; carpofossils representing fruits and seeds attributed to Itea europaea; flowers preserved in amber and assigned to Adenanthemum iteoides; and leaf impressions attributed to Itea. The distributions of these fossils indicate that Itea was present in western North America from the early Eocene to Miocene, in eastern North America beginning no later than the early Miocene, and in western Eurasia from the late Eocene to Pliocene. Only one datapoint is known from eastern Asia; it is early Miocene in age. Based on the fossil record, it can be inferred that Itea crossed between continents over both the Bering Land Bridge and North American Land Bridge, and that it reached Africa from Europe via Anatolia. Thus, it is predicted that the sole extant North American species, I. virginica, may be most closely related to the sole extant African species, I. rhamnoides. The potential application of Itea fossils to calibrating phylogenetic trees generated from molecular sequence data is also discussed.

Molecular phylogenetics and biogeography of the eastern Asian-eastern North American disjunctMitchellaand its close relativeDamnacanthus(Rubiaceae, Mitchelleae)

Mitchella is a small genus of the Rubiaceae with only two species. It is the only herbaceous semishrub of the family showing a disjunct distribution in eastern Asia and eastern North America, extending to Central America. Its phylogeny and biogeographical diversification remain poorly understood. In this study, we conducted phylogenetic and biogeographical analyses for Mitchella and its close relative Damnacanthus based on sequences of the nuclear internal transcribed spacer (ITS) and four plastid markers (rbcL, atpB-rbcL, rps16 and trnL-F). Mitchella is monophyletic, consisting of an eastern Asian M. undulata clade and a New World M. repens clade. Our results also support Michella as the closest relative to the eastern Asian Damnacanthus. The divergence time between the two intercontinental disjunct Mitchella species was dated to 7.73 Mya, with a 95% highest posterior density (HPD) of 3.14-12.53 Mya, using the Bayesian relaxed clock estimation. Ancestral area reconstructions suggest that the genus originated in eastern Asia. The semishrub Mitchella appears to have arisen from its woody ancestor in eastern Asia and then migrated to North America via the Bering land bridge in the late Miocene. (C) 2013 The Linnean Society of London Botanical Journal of the Linnean Society, 2013, 171, 395-412.

The enigmatic history of the European, Asian and American plethodontid salamanders

Recently published research addressing the question of relationships and biogeography of European plethodontid salamanders has refined time estimates for divergence from American relatives. The recently discovered Korean plethodontid Karsenia is either the sister-taxon of Hydromantes (which has members in Europe and California), or a close relative and co-member of a larger clade that originated in western North America, not eastern North America as formerly thought. The new information strengthens the biogeographical hypothesis that Hydromantes entered Eurasia via the Bering Land Bridge. Arguments are made favoring the placement of European and American relatives in a genus Hydromantes, with an American clade (subgenus Hydromantes) and a European clade (subgenera Atylodes and Speleomantes).

Molecular phylogeny and biogeography ofAstilbe(Saxifragaceae) in Asia and eastern North America

Phylogenetic analyses were conducted for Astilbe (Saxifragaceae), an Asian/eastern North American disjunct genus, using sequences of nuclear ribosomal internal transcribed spacer (ITS) and plastid matK, trnL-trnF and psbA-trnH regions. The monophyly of Astilbe is well supported by both ITS and plastid sequences. Topological incongruence was detected between the plastid and the ITS trees, particularly concerning the placement of the single North American species, A. biternata, which may be most probably explained by its origin involving hybridization and/or allopolyploidy with plastid capture. In Astilbe, all species with hermaphroditic flowers constitute a well-supported clade; dioecious species form a basal grade to the hermaphroditic clade. Astilbe was estimated to have split with Saxifragopsis from western North America at 20.69 Ma (95% HPD: 12.14–30.22 Ma) in the early Miocene. This intercontinental disjunction between Astilbe and Saxifragopsis most likely occurred via the Bering land bridge. The major clade of Astilbe (all species of the genus excluding A. platyphylla) was inferred to have a continental Asian origin. At least three subsequent migrations or dispersals were hypothesized to explain the expansion of Astilbe into North America, Japan and tropical Asian islands. The intercontinental disjunct lineage in Astilbe invokes a hybridization event either in eastern Asia or in North America. This disjunction in Astilbe may be explained by a Beringian migration around 3.54 Ma (95% high posterior density: 1.29–6.18 Ma) in the late Tertiary, although long-distance dispersal from eastern Asia to North America is also likely. The biogeographical connection between continental Asia, Taiwan, the Philippines and other tropical Asian islands in Astilbe provides evidence for the close floristic affinity between temperate or alpine south-western China and tropical Asia.

Phylogeny and biogeography of highly diverged freshwater fish species (Leuciscinae, Cyprinidae, Teleostei) inferred from mitochondrial genome analysis

The distribution of freshwater taxa is a good biogeographic model to study pattern and process of vicariance and dispersal. The subfamily Leuciscinae (Cyprinidae, Teleostei) consists of many species distributed widely in Eurasia and North America. Leuciscinae have been divided into two phyletic groups, leuciscin and phoxinin. The phylogenetic relationships between major clades within the subfamily are poorly understood, largely because of the overwhelming diversity of the group. The origin of the Far Eastern phoxinin is an interesting question regarding the evolutionary history of Leuciscinae. Here we present phylogenetic analysis of 31 species of Leuciscinae and outgroups based on complete mitochondrial genome sequences to clarify the phylogenetic relationships and to infer the evolutionary history of the subfamily.Phylogenetic analysis suggests that the Far Eastern phoxinin species comprised the monophyletic clades Tribolodon, Pseudaspius, Oreoleuciscus and Far Eastern Phoxinus. The Far Eastern phoxinin clade was independent of other Leuciscinae lineages and was closer to North American phoxinins than European leuciscins. All of our analysis also suggested that leuciscins and phoxinins each constituted monophyletic groups. Divergence time estimation suggested that Leuciscinae species diverged from outgroups such as Tincinae to be 83.3million years ago (Mya) in the Late Cretaceous and leuciscin and phoxinin shared a common ancestor 70.7Mya. Radiation of Leuciscinae lineages occurred during the Late Cretaceous to Paleocene. This period also witnessed the radiation of tetrapods. Reconstruction of ancestral areas indicates Leuciscinae species originated within Europe. Leuciscin species evolved in Europe and the ancestor of phoxinin was distributed in North America. The Far Eastern phoxinins would have dispersed from North America to Far East across the Beringia land bridge. The present study suggests important roles for the continental rearrangements during the Late Cretaceous to form the present-day distribution of organisms. Furthermore, the Late Cretaceous biotic turnover influenced for the modern terrestrial biodiversity.

Global biogeographical pattern of swallowtail diversification demonstrates alternative colonization routes in the Northern and Southern hemispheres

AbstractAimSwallowtail butterflies (Papilionidae) are a diverse and widespread group of insects that constitute a popular model system for ecological and evolutionary studies. We reconstruct the historical biogeography of Papilionidae to identify the dispersal or vicariance events that best explain their present‐day distribution, and test several proposed biogeographical hypotheses about the processes that shape distribution patterns in cosmopolitan groups.LocationWorld‐wide, with disjunct elements.MethodsThe phylogenetic relationships of 203 swallowtail species were determined by Bayesian inference using DNA data from mitochondrial (COI and COII) and nuclear (EF‐1α) genes. Divergence time estimates were inferred using Bayesian relaxed clock approaches. To investigate competing biogeographical hypotheses, geographical range evolution was reconstructed using recently developed approaches: (1) a Bayesian empirical approach to dispersal–vicariance analysis that takes phylogenetic uncertainty into account, and (2) a likelihood approach implementing the dispersal–extinction–cladogenesis model that uses time‐dependent stratified palaeogeographical matrices.ResultsOur biogeographical results are congruent regardless of the biogeographical approaches or dating estimates used and support the importance of dispersal events in shaping swallowtail distributions. Contrary to common observations for other groups, the origins and diversification of northern taxa are better explained by range expansion through the Bering land bridge than by the Thulean or De Geer routes. We also stress that the seemingly Gondwanan biogeographical pattern in the Southern Hemisphere is more likely to have resulted from multiple, independent, long‐distance dispersals than old vicariance events. The role of alternative colonization routes is also demonstrated for Madagascar, which facilitated multiple stepping‐stone colonizations from India or Southeast Asia to Africa, and also for South America via the Caribbean land bridge.Main conclusionsOverall, the present geographical distributions of swallowtails can be better explained by dispersal events than by the long‐held view of ancient vicariance events. This biogeographical study represents one of the most comprehensive phylogenetic and biogeographical studies on swallowtails. This work highlights the importance of using novel methodological approaches that provide the robust statistical frameworks needed to distinguish between competing biogeographical hypotheses. We emphasize the value of extensive taxonomic coverage for assessing the direction and frequency of supposedly rare events such as the multiple independent colonizations of Madagascar.

A rare case of Herpes zoster oticus in an immunocompetent patient

Varicella zoster virus (VZV) is an ancient virus. Herpes viruses have existed since the Devonian period, 400 milion years ago [1], when living creatures were represented by sharks, fish, amphibians. The origins of the ancestral VZV date from about 70-100 milion years ago (Cretaceous period) [2], the living creatures were dinosaurs, reptiles, snakes, amphibians, birds and mammals. Between 50-70 milion years ago VZV evolved in ancestral primates (derived from small mammals). In Africa 6 milion years ago VZV existed in hominids, then Homo erectus and finally Homo sapiens carried for a long period of time VZV. Homo sapiens migrated from Africa to China, India, subsequently to Europe. In North America Homo sapiens brought VZV from Asia (via Bering land bridge) 10.00015.000 years ago [2]. VZV causes two different disease: chickenpox (typically occurs in children) and herpes zoster (shingles) most often in adults and elderly persons (by the reactivation of latent VZV). Herpes zoster is a neurocutaneous disease characterised by cutaneous lesionsin a the areas of a cranial or spinal nerve. A few short remarks: usually a prodrome of dermatomal pain precedes the appearance of the rash and subsequent of typical lesions; the duration and intensity of zoster pain vary greatly even in immnucompetent persons, sometimes postherpetic neuralgia (PHN) may persist months-years and requires neurological consult; there are patients who experience acute segmental neuralgia without cutaneous eruption (zoster sine herpete); in these cases the rise of VZV antibodies represents a proof of diagnosis; zoster oticus is rare, even in immnuocompromised persons; facial paresis is reported in zoster oticus in immunocompetent patients; viral culture is the golden diagnostic standard; PCR detects VZV-DNA in fluids and tissues in some difficult cases; direct immunfluorescence assay with labeled VZV-specific monoclonal antibodies is rare recommended in practice, where we prefer Tzanck-test; Tzanck test is simple, not expensive, easy to perform, but unable to distinguish between VZV and HSV (herpes simplex virus) infection; extremely rare we perform skin biopsy to confirm diagnosis, even in zoster oticus; regarding the treatment we prescribe also Brivudin 125mg/ day 7 days to limit acute symptoms, to prevent PHN and complications of herpes.