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Two specimens of Borealosuchus collected from the lower facies of the Ravenscrag Formation (earliest Paleocene) in southern Saskatchewan are described. One largely complete individual featuring a partial skull, mandible, and postcrania can be unambiguously assigned to Borealosuchus griffithi Wu et al. 2001a. The other specimen consisting of skull and partial postcranial fragments is referred to Borealosuchus sternbergii Gilmore, 1910 based on diagnostic cranial features. These specimens confirm the earliest occurrence of this clade in the province of Saskatchewan and expand the known stratigraphic and geographic range of their respective species. The discovery of Borealosuchus griffithi and Borealosuchus sternbergii in proximity to each other within the same deposits suggests temporal and spatial range overlap in the Big Muddy area during the earliest Paleocene, hinting at possible niche partitioning or other ecological relationships between members of the same genus. Key words: range overlap, Puercan, crocodylians, crocodyliformes, niche partitioning Deux spécimens de Borealosuchu s prélevés du faciès inférieur de la Formation de Ravenscrag (début du Paléocène) dans le sud de la Saskatchewan sont décrits. Un individu presque complet présentant un crâne partiel, une mandibule et le post-crâne peut être affecté sans ambiguïté à Borealosuchus griffithi Wu et al., 2001a. L'autre spécimen, qui consiste en un crâne et des fragments post-crâniens partiels, est renvoyé à Borealosuchus sternbergii Gilmore, 1910 à la lumière de caractères crâniens diagnostiques. Ces spécimens confirment la présence la plus précoce de ce clade dans la province de la Saskatchewan et élargissent les aires de répartition stratigraphiques et géographiques connues de leurs espèces respectives. La découverte de Borealosuchus griffithi et Borealosuchus sternbergii à proximité l'un de l'autre dans les mêmes gisements indiquerait un chevauchement des aires de répartition temporelles et spatiales dans la région de Big Muddy au début du Paléocène, portant à croire à un possible partitionnement des niches ou d'autres relations écologiques entre des membres du même genre. [Traduit par la Rédaction] Mots-clés: chevauchement des aires de répartition, Puercéen, crocodiliens, crocodiliformes, partitionnement de niches, Introduction Crocodylians were once a common occurrence in the Western Interior of North America during the latest Cretaceous and early Cenozoic. Among the diverse lineages represented from the continent, Borealosuchus [...]

Twelve pairs of sister taxa in the speciose rockfish genus, Sebastes, overlap coastal distributions but are bathymetrically segregated. These pairs are ideal for comparative studies to understand how life-history traits, historical events, and environment interact to produce population genetic structure. Black rockfish, Sebastes melanops, forms one such pair. Its sister species, yellowtail rockfish (Sebastes flavidus), shows a genetic cline likely influenced by a dispersal barrier at Cape Mendocino, CA and northward range expansion. Due to geographic overlap and close systematic relationship, we predicted black rockfish was influenced by similar evolutionary processes and thus would show genetic pattern concordance with yellowtail rockfish. We analyzed ~ 1000 black rockfish from 22 sites spanning the species' range to test the null hypothesis of no structure, using the same markers that characterized yellowtail rockfish (i.e., 812 bp of the mitochondrial cytochrome b gene and six microsatellite loci). We reject the null hypothesis based on existence of at least three populations and microsatellite genetic divergence that separates the Alaskan and Continental U.S. populations (F.sub.CT = 0.021, p << 0.001), and a mitochondrial genetic cline near Cape Mendocino (F.sub.CT = 0.132, p < 0.01). We also found single collections genetically divergent from neighboring collections. Like yellowtail rockfish, oceanographic dispersal barriers and northern range expansion were inferred to influence black rockfish, however, unlike yellowtail rockfish, Cape Mendocino did not split the range into two stocks and was, therefore, inferred to be a less severe barrier. We hypothesize a higher frequency of extinction/recolonization events in black rockfish populations may have led to more complex genetic structure., Author(s): Jon E. Hess [sup.1] [sup.3] , John R. Hyde [sup.2] , Paul Moran [sup.1] Author Affiliations: (1) grid.420104.3, 0000 0001 1502 9269, Northwest Fisheries Science Center, , 2725 Montlake [...]

Species distribution patterns in the Brazilian Marine Province (BMP) are extensively debated, nevertheless no study used a multi-taxa approach to investigate possible biotic distinctions and the role of environmental factors in determining biogeographical patterns in this province. Here, we compiled the largest distributional multi-taxa dataset in the southern Atlantic (2412 reef species) to address the following: (1) similarities among areas accounting for species composition and environmental characteristics; (2) the absolute species richness of nine taxonomic groups among geographical bins; and (3) how species biogeographical patterns are explained by the environmental similarities. We hypothesized sub-provinces' limits will be strongly correlated to environmental delimitations, being sea surface temperature a central component influencing biotic subdivision on the BMP. We found eight different geographical bins considering the environmental factors, while five considering species distributions. We also observed a latitudinal gradient of species richness for most taxa, some presenting a 'mid-domain' shape pattern. Beta diversity among sub-provinces was low, and the nestedness component more important, indicating high connectivity along the BMP. Using a db-RDA, we demonstrated that environmental variables explained 64% of species clustering patterns, with sea surface temperature, water turbidity and current velocity explaining the biotic clustering of the Brazilian northeastern coast. Sub-provinces North and Abrolhos Bank were the most distinct areas regarding environmental and biotic data. Our study highlights the importance of using a multi-taxa approach to understand the relationship between biogeographical patterns, as well as its response to environmental and historical factors., Author(s): Isadora Cord [sup.1] , Lucas T. Nunes [sup.1] , Cristiane X. Barroso [sup.2] , Andrea S. Freire [sup.3] , Otto B. F. Gadig [sup.4] , Paula B. Gomes [sup.5] [...]

The variability of leaf stoichiometry has been studied at different taxonomic levels across various geographic ranges. However, the intraspecific variations in leaf stoichiometry of widely distributed species are poorly understood. We characterize the biogeographical patterns and environmental controls of leaf nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S) concentrations of Quercus variabilis Blume, a widely distributed tree species of significant economic and ecological value in China. The stoichiometry of Q. variabilis leaves exhibited substantial variation, which was strongly affected by climatic factors and respective concentrations of soil nutrients but had little association with leaf mass per area. Climate was the dominant driver, apart from P and Ca, which were also strongly related to soil P and Ca, respectively. Concentrations of leaf N, P, K, and Mg decreased significantly with mean annual temperature and increased with aridity, albeit at different magnitudes, resulting in positive latitudinal trends of all elements except for Ca and S. The results indicate that Q. variabilis leaf stoichiometry shows a relevant degree of flexibility and that alterations in climatic factors and soil nutrient availability have diverse influences on patterns of the different elements. Our findings provide an important contribution toward an understanding of how widespread species regulate their stoichiometry to adapt to heterogeneous environments. Key words: climatic factors, intraspecific variability, latitudinal pattern, leaf stoichiometry, soil nutrients, leaf mass per area. La variability de la strechiometrie foliaire a ete etudiee a differents niveaux taxonomiques et a travers differentes etendues geographiques. Cependant, les variations intraspecifiques de la strechiometrie foliaire d'especes largement repandues sont mal comprises. Nous avons caracterise les profils biogeographiques et les controles environnementaux des concentrations d'azote (N), de phosphore (P), de potassium (K), de calcium (Ca), de magnesium (Mg) et de soufre (S) dans les feuilles de Quercus variabilis Blume, une espece d'arbre tres repandue en Chine qui aune grande valeur economique et ecologique. La strechiometrie foliaire de Q. variabilis variait beaucoup et cette variation etait fortement influencee par les facteurs climatiques et les concentrations respectives des nutriments dans le sol, mais elle etait peu reliee a la masse surfacique des feuilles. Le climat etait le facteur dominant, a l'exception de P et Ca qui etaient aussi etroitement relies respectivement a P et Ca dans le sol. Les concentrations de N, P, K et Mg dans les feuilles diminuaient de facon significative en fonction de la temperature annuelle moyenne et augmentaient en fonction de l'aridite, bien qu'avec une ampleur differente, ce qui se traduisait par des tendances latitudinales positives pour tous les elements, sauf pour Ca et S. Les resultats indiquent que la strechiometrie foliaire de Q. variabilis montre un degre approprie de flexibilite et que les changements dans les facteurs climatiques et la disponibilite des nutriments dans le sol ont diverses influences sur les profils des differents elements. Nos resultats apportent une importante contribution pour comprendre comment les especes largement repandues regulent leur strechiometrie pour s'adapter a des environnements heterogenes. [Traduit par la Redaction] Mots-cles: facteurs climatiques, variabilite intraspecifique, profil latitudinal, strechiometrie foliaire, nutriments du sol, masse surfacique des feuilles., Introduction Leaf stoichiometry is a key measure in the study of plant nutrient limitations, nutrient cycling, and plant response to climate change (Gusewell 2004; Reich 2005; Esser et al. 2011; [...]

Mortality episodes have regularly been affecting the shellfish industry throughout its history. Some of these mortalities, especially in the oyster industry, have been attributed to herpesviruses. Purification of viral particles and molecular characterization have led to the development of routine monitoring, as well as improved taxonomic classification. Ostreid herpesviruses (Malacoherpesviridae), mostly affecting Pacific oysters Crassostrea gigas, have been sporadically recorded in the French oyster industry since the early 1990s (OsHV-1 'reference'). From 2008, a new variant of ostreid herpesvirus (OsHV-1 μVar) has emerged and seriously impacted oyster production in France and other European countries. Consequently, the presence of ostreid herpesviruses has been monitored in different oyster producing areas around the world. The present study compiles molecular data that are available from survey efforts and takes a biogeographical approach, in order to infer an origin for ostreid herpesviruses. The highest genotype diversity was found in East Asia, despite a lower survey effort in that area than in Europe. Genotype network analyses show that both populations of ostreid herpesviruses present in Europe (OsHV-1 'reference' and OsHV-1 μVar) are closely related to genotypes recorded in Asia. Moreover, ostreid herpesviruses have been detected in wild and symptom-free populations of various Asian native Crassostrea species. In the rest of the world, ostreid herpesvirus genotypes were recorded from cultivated C. gigas, and mostly associated with mortality episodes. Results of this study are therefore highly suggestive of an Asian origin for these viruses, which can be pathogenic under farming conditions. It also highlights the risks of European stock improvements, by means of overseas shellfish imports., Introduction Modern shellfish aquaculture is frequently affected by mortality episodes, especially during summer seasons. Such episodes are usually related to pathologies caused by viruses, bacteria, or eukaryote parasites, but also [...]

At broad geographical scales, the variation in bivalve shell thickness can be modulated by environmental factors that vary with latitude, such as sea surface temperature (SST), seawater pH, or calcium carbonate availability. Mussels usually form multilayered beds, and shell thickness is also expected to be affected by density and layering due to intraspecific competition. In this work, we explored the geographical variation of shell thickness in the intertidal mussel Perumytilus purpuratus between 18° and 42°S along the southeastern Pacific coast. We tested the hypothesis that there was a positive relationship between shell thickness and SST, and then we explored other variables that could have an effect on thickness, such as density, number of layers, and others environmental variables (pH and calcite concentration). The expected positive linear relationship between shell thickness and sea surface temperature was not found, but when the other population variables were included in the analysis, an unexpected inverse SST-thickness relationships appeared as significant, probably because this species could be adapted to colder and more acid seawater as are those of the tips of South America. Thickness was also negatively affected by density, which was expected for a gregarious species showing high intraspecific competition. Finally, our results highlight the importance of including density and crowding effects when macroscale patterns are explored, particularly in gregarious species, since these patterns could also be modulated by density-dependent processes, which might then override latitudinal trends of shell thickness when they are not included in the analyses., Introduction In gastropods and bivalves, shell shape and thickness may be plastic or adaptive traits (Boulding and Hay, 1993; Parsons, 1997; Beadman et al., 2003; Ubukata, 2003; Nagarajan et al., [...]

The varied topography of human skin offers a unique opportunity to study how the body's microenvironments influence the functional and taxonomic composition of microbial communities. Phylogenetic marker gene-based studies have identified many bacteria and fungi that colonize distinct skin niches. Here metagenomic analyses of diverse body sites in healthy humans demonstrate that local biogeography and strong individuality define the skin microbiome. We developed a relational analysis of bacterial, fungal and viral communities, which showed not only site specificity but also individual signatures. We further identified strain-level variation of dominant species as heterogeneous and multiphyletic. Reference-free analyses captured the uncharacterized metagenome through the development of a multi-kingdom gene catalogue, which was used to uncover genetic signatures of species lacking reference genomes. This work is foundational for human disease studies investigating inter-kingdom interactions, metabolic changes and strain tracking, and defines the dual influence of biogeography and individuality on microbial composition and function., Human skin harbours an abundant microbial ecosystem with bidirectional metabolic exchanges supporting symbiotic and commensal processes. The skin's surface consists of diverse microenvironments with distinct pH, temperature, moisture, sebum content [...]

The Fayum Depression of Egypt has produced a great diversity of fossil material, including marine and freshwater fishes. In contrast to the Eocene formations of the Fayum, the Oligocene Jbel Qatrani Formation has been more or less consistently considered to be deposited in a freshwater environment; however, the ichthyofauna indicates a more complex picture. Cenozoic fishes have been convincingly used to interpret the palaeoenvironment in which sediments were deposited. Based on the elasmobranch and osteichthyan faunas of the Jbel Qatrani Formation, we interpret that this formation was not deposited entirely in fresh waters, but had some marine influence, particularly in the lower part of the formation. The mixture of freshwater elements, such as polypterids and alestids, with brackish and marine elements, including myliobatid stingrays, in the Quarry E site suggests a local palaeoenvironment that was very close to the shoreline, in a less protected area, or under more seasonal influence than the rest of the sites in the formation. Additionally, the early Oligocene elasmobranch fishes from Quarry E have a strong biogeographic relationship with sites in Oman and Pakistan, in the eastern Tethys, representing a restricted fauna possibly limited in distribution by cooling global temperatures. La depression du Fayoum en Egypte a produit une grande variete de materiel fossile, dont des poissons marins et d'eau douce. Contrairement aux formations eocenes de la depression, la Formation oligocene de Jbel Qatrani est plus ou moins uniformement consideree comme ayant ete deposee dans un milieu dulcicole. Son ichtyofaune reflete toutefois un portrait plus complexe. Des poissons cenozoiques ont ete utilises de maniere convaincante pour interpreter le paleomilieu dans lequel les sediments ont ete deposes. A la lumiere des faunes d'elasmobranches et d'osteichtyens de la Formation de Jbel Qatrani, nous proposons que cette formation n'a pas ete deposee exclusivement en eau douce, mais qu'elle a egalement subi des influences marines, particulierement en ce qui concerne sa partie inferieure. Le melange, dans le site de la carriere E, d'elements d'eau douce, comme des polypterides et des alestides, et d'elements de milieu saumatre et marin, comme des myliobatides, donne a penser que le paleomilieu local etait tres proche du rivage, dans une zone moins protegee ou sous influence plus saisonniere que les autres sites de la formation. En outre, les elasmobranches de l'Oligocene precoce de la carriere E presentent un fort lien biogeographique avec des sites a Oman et au Pakistan, dans la Tethys orientale, representant une faune restreinte dont le refroidissement des temperatures planetaires a possiblement limite la repartition. [Traduit par le Redaction], Introduction The late Eocene to early Oligocene marked a period of transition from the warmer climates of the early Eocene to cooler global temperatures associated with the onset of glaciation [...]

We conducted a phylogeographic study of the Gambel's Quail (Callipepla gambelii) using sequences of the mitochondrial control region and NADH dehydrogenase subunit 2 (ND2) obtained from 167 specimens including hunter-harvested wings and museum study skins. The Gambel's Quail exhibited strong phylogeographic structure, large genetic gaps, and relatively high levels of haplotype (Hd = 0.79) and nucleotide diversity (π = 0.01). Thirty-four Gambel's Quail haplotypes clustered into two distinct haplogroups, with two additional highly divergent haplotypes. Distribution of the haplogroups was not concordant with sampled subspecies or ecogeographic regions; however, the overall distribution of the two haplogroups suggests that the Gambel's Quail may have been isolated in separate refugia of the Chihuahuan and Sonoran deserts during the Pleistocene. Both haplogroups appear to have undergone recent demographic expansion, possibly related to climatic changes associated with the onset of drier conditions in southwestern North America following the end of the Last Glacial Maximum. Received 17 July 2013. Accepted 7 December 2013. Key words: Callipepla gambelii, Gambel's Quail, mitochondrial DNA, phylogeography, population structure., Gambel's Quail (Callipepla gambelii) is a common resident of brushland and thorn-scrub habitats of southwestern North America. The geographic range of Gambel's Quail is centered in the Sonoran Desert and [...]

The Ucayali River is a major tributary of the Amazon, but it narrows considerably toward its headwater at the base of the Andes. This region, the upper Ucayali Valley, is of biological interest for the large number of closely related birds elsewhere separated from each other by major rivers that come into close proximity and potential contact. Between 2006-2011, we conducted the first modern ornithological inventory of the upper Ucayali River and sampled localities in all major avian habitats on either side of the river. We document the continued importance of the Ucayali River as a biogeographic barrier, even at the headwater, but also find that some mixing occurs, both in the form of taxa crossing to the 'wrong' bank and in the potential intergradation of distinct forms. We describe the biogeography of birds in the region, characterize the avifaunas of major habitats, and discuss in detail species of particular biogeographical interest. Received 25 August 2013. Accepted 10 January 2014. Key words: Amazonia, biogeography, range extension, river barrier, river island, Ucayali, white sand., The rivers of the Amazon Basin are important barriers to the distributions of terrestrial animals (Wallace 1852), even for relatively vagile taxa such as birds (Sick 1967, Haffer 1969). The [...]

This study provides an overview of the historical biogeography of the major clades of Apiales based on extensive taxon sampling from all major lineages of the order, and character sampling of sequence data from the plastid rpll6 intron and trnD-trY-trnE-trnT intergenic spacers. Divergence times were estimated in BEAST using relaxed molecular clocks and six calibration points from three families. Biogeographic reconstructions were estimated in DIVA and Lagrange using stratified and nonstratified models, addressing alternative scenarios for taxa with conflicting or poorly supported placements. Our analyses in BEAST estimated the origin of Apiales to Australasia in the Early Cretaceous (c.117 Ma). Most major clades also appear to have originated in Australasia, with the youngest family (Apiaceae) originating in the Late Cretaceous, c. 87 Ma. Diversification of the early lineages appears to be influenced by vicariance events related to the break up of Africa and Australasia (Torricelliaceae from Griseliniaceae and Apiineae), Australasia from Zealandia (e.g., Myodocarpaceae and Araliaceae), and Antarctica from South America, Australia, and possibly Africa (main lineages of Apiaceae). Long-distance dispersal appears as the likely explanation for many younger lineages within major clades, including Subantarctic pathways (e.g., Griseliniaceae and Azorelloideae), across the Pacific and Indian Ocean Basins (e.g., Pittosporaceae and Araliaceae), from Asia across Europe into the Americas (Araliaceae). Keywords Apiales * Apiaceae * Araliaceae * Australasia * Antarctica * Cretaceous, Introduction The dicot order Apiales exhibits a worldwide geographic distribution, in which its two most speciose families have a center of diversity either in the north temperate zone (Apiaceae) or [...]

Discriminating genotypes within plant collections is imperative, and DNA sequence approaches for detecting single nucleotide polymorphisms (SNPs) have proved essential in any modern analysis of germplasm. By sequencing the α-Phs and PvFROl genes that, respectively, encode phaseolin and an iron reductase, we prospected for SNPs in exonic and intronic regions of both genes in a sample of 31 accessions of Phaseolus vulgaris from Mesoamerican and Andean gene pools, and one accession of Phaseolus lunatus, chosen as an outgroup. Sequence alignment showed 95 SNPs in α-Phs and 83 in PvFROl, but diversity along the nucleotide sequences was not evenly distributed in both genes. Accessions from the same gene pool showed greater similarity than those from different gene pools, and the cluster patterns obtained in this study were consistent with the hierarchical organization into two P. vulgaris gene pools. The polymorphisms detected in the α-Phs gene allowed better discrimination among the accessions within each cluster than the PvFROl polymorphisms. Furthermore, some variations within exons changes amino acids in both predicted protein sequences. In an unprecedented result, the phaseolin-predicted amino acid variation allowed most of the accessions to be typified. Key words: common bean, nucleotide diversity, single nucleotide polymorphism, phaseolin, iron reductase, predicted amino acid variation. La capacite de distinguer des genotypes au sein de collections de materiel genetique est capitale et les analyses de sequences d'ADN, permettant de detecter des polymorphismes mononucleotidiques (SNP), se sont averees essentielles dans toute analyse moderne du germoplasme. En sequencant les genes α-Phs et PvFRO1, lesquels codent respectivement pour la phaseoline et une reductase du fer, les auteurs ont cherche a identifier des SNP au sein des exons et introns des deux genes au sein d'un echantillon de 31 accessions du Phaseolus vulgaris provenant des pools geniques mesoamericain et andeen, ainsi qu'une accession du Phaseolus lunatus comme groupe externe. L'alignement des sequences a revele 95 SNP au sein de l'α-Phs et 83 au sein de PvFRO1, mais cette diversite n'etait pas uniformement repartie au sein des genes. Les accessions d'un meme pool genique presentaient une plus grande similarite que celles appartenant a des pools differents, et les groupements observes dans ce travail etaient conformes a une organisation hierarchique au sein des deux pools geniques du P. vulgaris. Les polymorphismes detectes dans le gene α-Phs ont permis une meilleure discrimination entre les accessions au sein de chaque groupe que les polymorphisms au sein de PvFRO1. De plus, certains variants au sein des exons entrainaient des changements dans chacune des sequences peptidiques predites. De maniere inattendue, la variation notee au niveau de la sequence peptidique predite de la phaseoline permettait de distinguer pratiquement toutes les accessions. [Traduit par la Redaction] Mots-cles: haricot, diversite nucleotidique, polymorphismes mononucleotidiques, phaseoline, reductase du fer, variation dans la sequence peptidique predite., Introduction The geographical origins of the common bean (Phaseolus vulgaris L.) are well documented, and two large gene pools have been recognized in Mesoamerica and in the Andes where domestication [...]

Ectothermal organisms distributed along environmental gradients in a wide geographical distribution display extensive phenotypic variation. This is particularly pervasive along latitudinal clines, which are linked to gradual changes in environmental factors. Widespread species may also be distributed among biogeographic breaks, which in contrast to smooth clines, often show abrupt changes in phenotypic traits. In species with widespread latitudinal distribution that also encompass important biogeographical breaks, it is not clear which of those factors prevails on shaping the phenotypic variation or if some traits are particularly more sensitive to one or the other. To evaluate this, we measured 4 fitness-related traits in 6 populations of the intertidal snapping shrimp Betaeus truncatus, as its distribution along Chile expands over 40° in latitude and three major biogeographical provinces. Here, we statistically evaluated the role of both, latitude and biogeographic breaks, on mean population values of fitness-related traits but also on the variances and covariances (i.e., P-matrix) between them. Overall, our results (1) indicate that latitude is more important than breaks in shaping the phenotypic variation of most of these fitness-related traits, (2) show that the differences in the variance-covariance relationship among traits between the extremes of the gradient arises from gradual increases in variance and rather sharp changes in covariance at mid-latitudes and (3) show that at present, it is difficult to unambiguously determine whether natural selection or plasticity is responsible for the observed pattern in means, variances and covariances and only further work might disentangle these possibilities., Introduction Ectothermal organisms distributed along environmental gradients in a wide geographical distribution display extensive variation in life-history (Lardies et al. 2010), morphological (Hoffmann and Sgro 2011) and physiological traits (Lardies [...]