Frankbaronia velata nov. sp., a putative peronosporomycete oogonium containing multiple oospores from the Lower Devonian Rhynie chert

Spherical to pyriform microfossils containing multiple smooth-walled spherules from the Lower Devonian Rhynie chert are described as oogonia of a new fossil peronosporomycete based on congruencies in basic morphology to the polyoosporous oogonia of certain extant Saprolegniales. Because the new fossils also resemble Frankbaronia polyspora, a putative peronosporomycete described previously from the Rhynie chert, they are assigned to the fossil genus Frankbaronia and formally proposed as a new species, F. velata. Surrounding the oogonium is a conspicuous sheath of consolidated mucilage, produced and secreted by the oogonium during development. The discovery of F. velata adds to our understanding of the microbial diversity in early terrestrial ecosystems, and contributes to the documentation of the evolutionary history of the Peronosporomycetes.Kugelige bis tropfenförmige, glattwandige kugelige Strukturen in großer Zahl enthaltende Mikrofossilien aus dem unterdevonischen Rhynie Chert werden als Oogonien eines neuen fossilen Peronosporomyzeten beschrieben, da sie den polyoosporen Oogonien einiger heutiger Saprolegniales morphologisch sehr ähnlich sind. Da die Fossilien auch mit Frankbaronia polyspora, einem bereits früher aus dem Rhynie Chert beschriebenen vermeintlichen Peronosporomyzeten, gut vergleichbar sind, werden sie ebenfalls in die Gattung Frankbaronia gestellt und als neue Art, F. velata, eingeführt. Die Oogonien sind von einer auffälligen Hülle aus konsolidiertem Schleim umgeben, welcher vom sich entwickelnden Oogonium produziert und sekretiert wurde. Frankbaronia velata trägt zu einem besseren Verständnis der mikrobiellen Diversität in frühen terrestrischen Ökosystemen sowie zur Dokumentation der Evolutionsgeschichte der Peronosporomycetes bei

Structurally preserved fungi from Antarctica: diversity and interactions in late Palaeozoic and Mesozoic polar forest ecosystems

Chert and silicified wood from the Permian through Cretaceous of Antarctica contain abundant information on fungal diversity and plant-fungal interactions. The chert deposits represent a particularly interesting setting for the study of plant-fungal interactions because they preserve remains of distinctive high latitude forest ecosystems with polar light regimes that underwent a profound climate change from icehouse to greenhouse conditions. Moreover, some of the cherts and wood show the predominance of extinct groups of seed plants (e.g. Glossopteridales, Corystospermales). Over the past 30 years, documentation of fossil fungi from Antarctica has shifted from a by-product of plant descriptive studies to a focused research effort. This paper critically reviews the published record of fungi and fungal associations and interactions in the late Palaeozoic and Mesozoic cherts and silicified wood from Antarctica;certain fungal palynomorphs and fungal remains associated with adpression fossils and cuticles are also considered. Evidence of mutualistic (mycorrhizal), parasitic and saprotrophic fungi associated with plant roots, stems, leaves and reproductive organs is presented, together with fungi occurring within the peat matrix and animal-fungus interactions. Special attention is paid to the morphology of the fungi, their systematic position and features that can be used to infer fungal nutritional modes

Structurally preserved fungi from Antarctica: diversity and interactions in late Palaeozoic and Mesozoic polar forest ecosystems

Chert and silicified wood from the Permian through Cretaceous of Antarctica contain abundant information on fungal diversity and plant-fungal interactions. The chert deposits represent a particularly interesting setting for the study of plant-fungal interactions because they preserve remains of distinctive high latitude forest ecosystems with polar light regimes that underwent a profound climate change from icehouse to greenhouse conditions. Moreover, some of the cherts and wood show the predominance of extinct groups of seed plants (e.g. Glossopteridales, Corystospermales). Over the past 30 years, documentation of fossil fungi from Antarctica has shifted from a by-product of plant descriptive studies to a focused research effort. This paper critically reviews the published record of fungi and fungal associations and interactions in the late Palaeozoic and Mesozoic cherts and silicified wood from Antarctica;certain fungal palynomorphs and fungal remains associated with adpression fossils and cuticles are also considered. Evidence of mutualistic (mycorrhizal), parasitic and saprotrophic fungi associated with plant roots, stems, leaves and reproductive organs is presented, together with fungi occurring within the peat matrix and animal-fungus interactions. Special attention is paid to the morphology of the fungi, their systematic position and features that can be used to infer fungal nutritional modes

Fungi associated with Glossopteris (Glossopteridales) leaves from the Permian of Antarctica

Fungi today occur on virtually every plant part, living and dead, and represent a significant proportion of fungal diversity. Arborescent seed ferns characterized by large, tongue-shaped leaves with reticulate venation (Glossopteris) represent the dominant floral element in the Permian of Gondwana. However, documented evidence of fungi associated with the leaves of these plants is exceedingly rare. Partially degraded Glossopteris leaves from two upper Permian permineralized peat deposits from Antarctica yield scattered evidence of fungal colonization in the form of hyphae, spores, sporangia, and mycelia. Intact leaves from the same deposits are typically free of fungi, suggesting that the fungi in the degraded leaves were saprotrophs on the forest floor, rather than colonizers of living leaves. We hypothesize that the scarcity of fungi associated with Antarctic Glossopteris leaves may be related to structural and physiological adaptions of the plants to the extreme conditions that governed late Paleozoic polar ecosystems.Lebende und tote Pflanzenteile besiedelnde Pilze stellen heute einen großen Teil der Gesamtdiversität der Pilze dar. BaumförmigeSamenfarne mit großen, zungenförmigen Blättern mit Netznervatur (Glossopteris) waren sehr weit verbreitet im Perm von Gondwana. Nachweise für Pilze auf und in den Blättern dieser Pflanzen sind allerdings bis heute sehr selten. Verrottete und zum Teil zerstörte Glossopteris Blätter aus permineralisiertem Torf von zwei Fundstellen in der Antarktis weisen Spuren einer Besiedlung durch Pilze in Form von Hyphen, Sporen, Sporangien und Myzelien auf. Intakte Blätter aus denselben Torfen sind allerdings in der Regel frei von Pilzen, was vermuten läßt, dass die Pilze in den verotteten Blättern saprotroph waren und nicht lebende Blätter besiedelten. Das Fehlen von Pilzen auf/in intakten Glossopteris Blättern könnte mit bestimmten Anpassungen der Pflanzen an die extremen Bedingungen zusammenhängen, denen die jungpaläozoischen polaren Ökosysteme ausgesetzt waren

Early Jurassic silicified woods from Carapace Nunatak, South Victoria Land, Antarctica

The Jurassic vegetation of Antarctica remains poorly known and, while there have been several reports of large fossil trees from that time period across the continent, detailed anatomical studies of their wood are extremely scarce. Here we describe new silicified woods of Early Jurassic (probably Toarcian) age from Carapace Nunatak, South Victoria Land. The genera Agathoxylon and Brachyoxylon are formally recognized for the first time in the Jurassic of Antarctica. The preservation of the woods is imperfect, which is likely explained by the presence in some of the specimens of fungi, whose anatomical structures are described in detail. Combined with previous reports of pollen, leaves, and cones from South and North Victoria Land, these new specimens support the presence of several conifer families in the Early Jurassic floras of the region

Low-Altitude UAV Imaging Accurately Quantifies Eelgrass Wasting Disease From Alaska to California

Declines in eelgrass, an important and widespread coastal habitat, are associated with wasting disease in recent outbreaks on the Pacific coast of North America. This study presents a novel method for mapping and predicting wasting disease using Unoccupied Aerial Vehicle (UAV) with low-altitude autonomous imaging of visible bands. We conducted UAV mapping and sampling in intertidal eelgrass beds across multiple sites in Alaska, British Columbia, and California. We designed and implemented a UAV low-altitude mapping protocol to detect disease prevalence and validated against in situ results. Our analysis revealed that green leaf area index derived from UAV imagery was a strong and significant (inverse) predictor of spatial distribution and severity of wasting disease measured on the ground, especially for regions with extensive disease infection. This study highlights a novel, efficient, and portable method to investigate seagrass disease at landscape scales across geographic regions and conditions

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde