scholarly journals An Updated Infrageneric Classification of the North American Oaks (Quercus Subgenus Quercus): Review of the Contribution of Phylogenomic Data to Biogeography and Species Diversity

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 786
Author(s):  
Paul S. Manos ◽  
Andrew L. Hipp
Keyword(s):  
North America ◽  
North American ◽  
Sister Group ◽  
Regional Patterns ◽  
Infrageneric Classification ◽  
Biogeographic Patterns ◽  
The North ◽  
Species Complexes ◽  
The Impact

The oak flora of North America north of Mexico is both phylogenetically diverse and species-rich, including 92 species placed in five sections of subgenus Quercus, the oak clade centered on the Americas. Despite phylogenetic and taxonomic progress on the genus over the past 45 years, classification of species at the subsectional level remains unchanged since the early treatments by WL Trelease, AA Camus, and CH Muller. In recent work, we used a RAD-seq based phylogeny including 250 species sampled from throughout the Americas and Eurasia to reconstruct the timing and biogeography of the North American oak radiation. This work demonstrates that the North American oak flora comprises mostly regional species radiations with limited phylogenetic affinities to Mexican clades, and two sister group connections to Eurasia. Using this framework, we describe the regional patterns of oak diversity within North America and formally classify 62 species into nine major North American subsections within sections Lobatae (the red oaks) and Quercus (the white oaks), the two largest sections of subgenus Quercus. We also distill emerging evolutionary and biogeographic patterns based on the impact of phylogenomic data on the systematics of multiple species complexes and instances of hybridization.

scholarly journals Novel Highly Pathogenic Avian A(H5N2) and A(H5N8) Influenza Viruses of Clade 2.3.4.4 from North America Have Limited Capacity for Replication and Transmission in Mammals

mSphere ◽  
2016 ◽  
Vol 1 (2) ◽  
Author(s):  
Bryan S. Kaplan ◽  
Marion Russier ◽  
Trushar Jeevan ◽  
Bindumadhav Marathe ◽  
Elena A. Govorkova ◽  
...  
Keyword(s):  
North America ◽  
Avian Influenza ◽  
North American ◽  
Influenza Viruses ◽  
Morbidity And Mortality ◽  
Avian Influenza Viruses ◽  
Highly Pathogenic ◽  
The North ◽  
Domestic Poultry ◽  
The Impact

ABSTRACT Highly pathogenic H5 influenza viruses have been introduced into North America from Asia, causing extensive morbidity and mortality in domestic poultry. The introduced viruses have reassorted with North American avian influenza viruses, generating viral genotypes not seen on other continents. The experiments and analyses presented here were designed to assess the impact of this genetic diversification on viral phenotypes, particularly as regards mammalian hosts, by comparing the North American viruses with their Eurasian precursor viruses. Highly pathogenic influenza A(H5N8) viruses from clade 2.3.4.4 were introduced to North America by migratory birds in the fall of 2014. Reassortment of A(H5N8) viruses with avian viruses of North American lineage resulted in the generation of novel A(H5N2) viruses with novel genotypes. Through sequencing of recent avian influenza viruses, we identified PB1 and NP gene segments very similar to those in the viruses isolated from North American waterfowl prior to the introduction of A(H5N8) to North America, highlighting these bird species in the origin of reassortant A(H5N2) viruses. While they were highly virulent and transmissible in poultry, we found A(H5N2) viruses to be low pathogenic in mice and ferrets, and replication was limited in both hosts compared with those of recent highly pathogenic avian influenza (HPAI) H5N1 viruses. Molecular characterization of the hemagglutinin protein from A(H5N2) viruses showed that the receptor binding preference, cleavage, and pH of activation were highly adapted for replication in avian species and similar to those of other 2.3.4.4 viruses. In addition, North American and Eurasian clade 2.3.4.4 H5NX viruses replicated to significantly lower titers in differentiated normal human bronchial epithelial cells than did seasonal human A(H1N1) and highly pathogenic A(H5N1) viruses isolated from a human case. Thus, despite their having a high impact on poultry, our findings suggest that the recently emerging North American A(H5N2) viruses are not expected to pose a substantial threat to humans and other mammals without further reassortment and/or adaptation and that reassortment with North American viruses has not had a major impact on viral phenotype. IMPORTANCE Highly pathogenic H5 influenza viruses have been introduced into North America from Asia, causing extensive morbidity and mortality in domestic poultry. The introduced viruses have reassorted with North American avian influenza viruses, generating viral genotypes not seen on other continents. The experiments and analyses presented here were designed to assess the impact of this genetic diversification on viral phenotypes, particularly as regards mammalian hosts, by comparing the North American viruses with their Eurasian precursor viruses.

Ecogeography and the Great American Interchange

Paleobiology ◽  
1991 ◽  
Vol 17 (3) ◽  
pp. 266-280 ◽  
Author(s):  
S. David Webb
Keyword(s):  
North America ◽  
South America ◽  
North American ◽  
Mammalian Fauna ◽  
The South ◽  
Land Bridge ◽  
Southern Mexico ◽  
The North ◽  
Land Mammal ◽  
The Impact

When the isthmian land bridge triggered the Great American Interchange, a large majority of land-mammal families crossed reciprocally between North and South America at about 2.5 Ma (i.e., Late Pliocene). Initially land-mammal dynamics proceeded as predicted by equilibrium theory, with roughly equal reciprocal mingling on both continents. Also as predicted, the impact of the interchange faded in North America after about 1 m.y. In South America, contrary to such predictions, the interchange became decidedly unbalanced: during the Pleistocene, groups of North American origin continued to diversify at exponential rates. Whereas only about 10% of North American genera are derived from southern immigrants, more than half of the modern mammalian fauna of South America, measured at the generic level, stems from northern immigrants. In addition, extinctions more severely decimated interchange taxa in North America, where six families were lost, than in South America, where only two immigrant families became extinct.This paper presents a two-phase ecogeographic model to explain the asymmetrical results of the land-mammal interchange. During the humid interglacial phase, the tropics were dominated by rain forests, and the principal biotic movement was from Amazonia to Central America and southern Mexico. During the more arid glacial phase, savanna habitats extended broadly right through tropical latitudes. Because the source area in the temperate north was six times as large as that in the south, immigrants from the north outnumbered those from the south. One prediction of this hypothesis is that immigrants from the north generally should reach higher latitudes in South America than the opposing contingent of land-mammal taxa in North America. Another prediction is that successful interchange families from the north should experience much of their phylogenetic diversification in low latitudes of North America before the interchange. Insofar as these predictions can be tested, they appear to be upheld.

scholarly journals The Impact of Large-Scale Orography on Northern Hemisphere Winter Synoptic Temperature Variability

2019 ◽  
Vol 32 (18) ◽  
pp. 5799-5814 ◽  
Author(s):  
Nicholas J. Lutsko ◽  
Jane Wilson Baldwin ◽  
Timothy W. Cronin
Keyword(s):  
North America ◽  
Northern Hemisphere ◽  
North American ◽  
Large Scale ◽  
Temperature Variability ◽  
Temperature Gradients ◽  
Northwest Pacific ◽  
Near Surface ◽  
The North ◽  
The Impact

Abstract The impact of large-scale orography on wintertime near-surface (850 hPa) temperature variability on daily and synoptic time scales (from days to weeks) in the Northern Hemisphere is investigated. Using a combination of theory, idealized modeling work, and simulations with a comprehensive climate model, it is shown that large-scale orography reduces upstream temperature gradients, in turn reducing upstream temperature variability, and enhances downstream temperature gradients, enhancing downstream temperature variability. Hence, the presence of the Rockies on the western edge of the North American continent increases temperature gradients over North America and, consequently, increases North American temperature variability. By contrast, the presence of the Tibetan Plateau and the Himalayas on the eastern edge of the Eurasian continent damps temperature variability over most of Eurasia. However, Tibet and the Himalayas also interfere with the downstream development of storms in the North Pacific storm track, and thus damp temperature variability over North America, by approximately as much as the Rockies enhance it. Large-scale orography is also shown to impact the skewness of downstream temperature distributions, as temperatures to the north of the enhanced temperature gradients are more positively skewed while temperatures to the south are more negatively skewed. This effect is most clearly seen in the northwest Pacific, off the east coast of Japan.

scholarly journals Case studies of ozone transport between North America and Europe in summer 2000

2005 ◽  
Vol 5 (4) ◽  
pp. 6127-6184 ◽  
Author(s):  
G. Guerova ◽  
I. Bey ◽  
J.-L. Attié ◽  
R. V. Martin
Keyword(s):  
North America ◽  
North American ◽  
North Atlantic Ocean ◽  
Conveyor Belt ◽  
Tropospheric Chemistry ◽  
Pollution Transport ◽  
The North ◽  
Range Transport ◽  
European Mountain ◽  
The Impact

Abstract. This paper reports on Long Range Transport (LRT) of ozone and related species over the North Atlantic ocean and its impact on Europe. Measurements of NO2 and O3 columns from the GOME and MOPITT satellite instruments are first used in conjunction with the GEOS-CHEM global model of transport and tropospheric chemistry to identify the major events of LRT that reach Europe over the course of the summer 2000. Model simulations are then used to examine surface O3 observations at a European mountain site and O3 vertical profiles over several European cities to quantify the impact of the LRT events on the European ozone distributions. Over the course of summer 2000, we identified nine major episodes of pollution transport between North America and Europe, which are in majority associated with WCB/post-frontal outflow (7 events) and zonal transport (2 events). We find that on average three episodes occur per month with the strongest ones being in June. The number and frequency of LRT events that reach Europe after leaving North America is strongly driven by the position and strength of the Azores anticyclone. After leaving North America, the plumes can either i) travel in the North American cyclones, mostly in the Warm Conveyor Belt (WCB), tracking poleward and thus reach Europe at high latitudes; ii) be transported zonally between 40° and 55° N directly to Europe; iii) be incorporated into the Azores anticyclone and reach Europe at mid-latitudes. Based on model sensitivity simulation it can be concluded that on average the North American sources of ozone contribute between 2–8 ppb in PBL and 10–13 ppb in FT. During particular episodes the North American sources resulted in O3 enhancement up to 25–28 ppb in the layer between 800–600 hPa and 10–12 ppb in PBL. For some episodes a substantial North American contribution (30% or higher) does not translate into a well marked enhancement of the total O3.

REVISION OF NORTH AMERICAN AGABUS LEACH (COLEOPTERA: DYTISCIDAE): INTRODUCTION, KEY TO SPECIES GROUPS, AND CLASSIFICATION OF THE AMBIGUUS-, TRISTIS-, AND ARCTICUS-GROUPS

1989 ◽  
Vol 121 (10) ◽  
pp. 861-919 ◽  
Author(s):  
D.J. Larson
Keyword(s):  
North America ◽  
North American ◽  
North American Species ◽  
Key To Species ◽  
Diagnostic Characters ◽  
Ecological Information ◽  
The North ◽  
Species Groups ◽  
Diving Beetle

AbstractThe first of a planned series of papers revising the Nearctic species of the predaceous diving beetle genus, Agabus Leach, is presented. The genus is defined in the broad sense of Sharp (1882) and Fall (1922). The North American species are divided into species groups and diagnostic characters for group recognition are summarized in a key. Assignment of species to these groups is indicated in a checklist of North American species. The ambiguus-, tristis-, and arcticus-groups are defined, their relationships discussed, and included species revised. The ambiguus-group, which is restricted to North America, contains the species A. ambiguus (Say), A. strigulosis (Crotch), A. erythropterus (Say), A. austinii Sharp, and A. klamathensis sp.nov. The tristis-group, which has a Holarctic distribution, contains two species in North America, A. tristis Aubé and A. leptapsis (LeConte). The Holarctic arcticus-group is represented by A. arcticus (Paykull) and A. anthracinus (Mannerheim) in North America. For each species, patterns of variation are described, the North American distributions mapped, and ecological information summarized.

scholarly journals Cortinarius subgenus Leprocybe, unexpected diversity and significant differences in species compositions between western and eastern North America

2021 ◽  
Author(s):  
J. Ammirati ◽  
K. Liimatainen ◽  
D. Bojantchev ◽  
U. Peintner ◽  
R. Kuhnert-Finkernagel ◽  
...  
Keyword(s):  
North America ◽  
North American ◽  
Molecular Data ◽  
North American Species ◽  
Eastern North America ◽  
Type Specimens ◽  
European Species ◽  
The North ◽  
Morphological And Molecular Data

The focus of this paper is the North American species of Cortinarius in subg. Leprocybe. Eighteen species, including twelve new ones, and two tentative (aff.) species, are delimited based on morphological and molecular data (DNA ITS-LSU sequences). Existing type specimens of species in subg. Leprocybe were also studied, and neo- or epitypes designated for C. cotoneus, C. melanotus, C. phrygianus and C. venetus to stabilize the nomenclature. In addition, to improve the infrasubgeneric classification of Leprocybe three new sections are proposed: sect. Fuscotomentosi, sect. Melanoti and sect. Squamiveneti. This study adds substantial information to the knowledge of subg. Leprocybe in North America against a background of European species. To date only two species, C. phrygianus and C. squamivenetus have been reported from both continents.

Ordovician

1992 ◽  
Vol 13 (1) ◽  
pp. 19-36 ◽  
Author(s):  
R. E. Bevins ◽  
B. J. Bluck ◽  
P. J. Brenchley ◽  
R. A. Fortey ◽  
C. P. Hughes ◽  
...  
Keyword(s):  
General Practice ◽  
North America ◽  
North American ◽  
Direct Application ◽  
Geological Society ◽  
Central Belt ◽  
The North ◽  
Upper Limit

AbstractSince the publication of the Cambrian and Ordovician correlation charts by the Geological Society (Cowie et al. 1972; Williams et al. 1972) it has become more general practice to include the Tremadoc Series in the Ordovician, and although the precise level at which the base of the Ordovician is to be drawn is not finally decided, the limits of the system are generally understood. The upper limit has now been precisely defined at the base of Parakidograptus acuminatus Biozone, as exposed at Dob's Linn in the central belt of the Southern Uplands in south Scotland, the underlying Glyptograptus persculptus Biozone being relegated to the Hirnantian Stage of the Ashgill Series in the Ordovician System (Cocks & Rickards 1988).Standard international series for the Ordovician are yet to be decided upon but in Britain the series usually employed are those which have been defined and refined over a period of more than a hundred years, based on successions in Wales, the Welsh Borderland and the north of England, namely: Tremadoc Arenig, Llanvirn, Llandeilo, Caradoc and Ashgill. These have ready application in the Anglo-Welsh area and further afield, particularly in continental Europe and Asia, but the demonstration that the faunas of Scotland and northwestern Ireland have much more in common with those of Laurentia (North America, Greenland and Spitsbergen) makes the direct application of many of these chronostratigraphical terms less relevant than the scheme which has developed for the classification of the North American Ordovician. The latter is still to some extent

Diversification of the North American Doellingeria-Eucephalus Clade (Astereae: Asteraceae) Inferred from Molecular and Morphological Evidence

2019 ◽  
Vol 44 (4) ◽  
pp. 930-942
Author(s):  
Geraldine A. Allen ◽  
Luc Brouillet ◽  
John C. Semple ◽  
Heidi J. Guest ◽  
Robert Underhill
Keyword(s):  
North American ◽  
Sequence Data ◽  
Phylogenetic Analyses ◽  
Sister Group ◽  
Morphological Evidence ◽  
South American ◽  
New Combinations ◽  
The North ◽  
Hybridization Event ◽  
Ancient Hybridization

Abstract—Doellingeria and Eucephalus form the earliest-diverging clade of the North American Astereae lineage. Phylogenetic analyses of both nuclear and plastid sequence data show that the Doellingeria-Eucephalus clade consists of two main subclades that differ from current circumscriptions of the two genera. Doellingeria is the sister group to E. elegans, and the Doellingeria + E. elegans subclade in turn is sister to the subclade containing all remaining species of Eucephalus. In the plastid phylogeny, the two subclades are deeply divergent, a pattern that is consistent with an ancient hybridization event involving ancestral species of the Doellingeria-Eucephalus clade and an ancestral taxon of a related North American or South American group. Divergence of the two Doellingeria-Eucephalus subclades may have occurred in association with northward migration from South American ancestors. We combine these two genera under the older of the two names, Doellingeria, and propose 12 new combinations (10 species and two varieties) for all species of Eucephalus.

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