Diversity and ecological adaptations in Palaeogene lichens

Lichens are highly specialized symbioses between heterotrophic fungi and photoautotrophic green algae or cyanobacteria. The mycobionts of many lichens produce morphologically complex thalli to house their photobionts. Lichens play important roles in ecosystems and have been used as indicators of environmental change. Here we report the finding of 152 new fossil lichens from European Palaeogene amber, and hence increase the total number of known fossil lichens from 15 to 167. Most of the fossils represent extant lineages of the Lecanoromycetes, an almost exclusively lichen-symbiotic class of Ascomycota. The fossil lichens show a wide diversity of morphological adaptations that attached epiphytic thalli to their substrates, helped to combine external water storage with effective gas exchange and facilitated the simultaneous reproduction and dispersal of both partners in symbiosis. The fossil thallus morphologies suggest that the climate of European Palaeogene amber forests was relatively humid and most likely temperate.Peer reviewe

Melting of Discrete Vortices via Quantum Fluctuations

We consider nonlinear boson states with a nontrivial phase structure in the three-site Bose-Hubbard ring, {\em quantum discrete vortices} (or {\em q-vortices}), and study their "melting" under the action of quantum fluctuations. We calculate the spatial correlations in the ground states to show the superfluid-insulator crossover and analyze the fidelity between the exact and variational ground states to explore the validity of the classical analysis. We examine the phase coherence and the effect of quantum fluctuations on q-vortices and reveal that the breakdown of these coherent structures through quantum fluctuations accompanies the superfluid-insulator crossover.Comment: Revised version, 4 pages, 5 figures, Accepted for publication in Physical Review Letter

Space station impact experiments

Four processes serve to illustrate potential areas of study and their implications for general problems in planetary science. First, accretional processes reflect the success of collisional aggregation over collisional destruction during the early history of the solar system. Second, both catastrophic and less severe effects of impacts on planetary bodies survivng from the time of the early solar system may be expressed by asteroid/planetary spin rates, spin orientations, asteroid size distributions, and perhaps the origin of the Moon. Third, the surfaces of planetary bodies directly record the effects of impacts in the form of craters; these records have wide-ranging implications. Fourth, regoliths evolution of asteroidal surfaces is a consequence of cumulative impacts, but the absence of a significant gravity term may profoundly affect the retention of shocked fractions and agglutinate build-up, thereby biasing the correct interpretations of spectral reflectance data. An impact facility on the Space Station would provide the controlled conditions necessary to explore such processes either through direct simulation of conditions or indirect simulation of certain parameters

Morphological stasis in the first myxomycete from the Mesozoic, and the likely role of cryptobiosis

Myxomycetes constitute a group within the Amoebozoa well known for their motile plasmodia and morphologically complex fruiting bodies. One obstacle hindering studies of myxomycete evolution is that their fossils are exceedingly rare, so evolutionary analyses of this supposedly ancient lineage of amoebozoans are restricted to extant taxa. Molecular data have significantly advanced myxomycete systematics, but the evolutionary history of individual lineages and their ecological adaptations remain unknown. Here, we report exquisitely preserved myxomycete sporocarps in amber from Myanmar, ca. 100 million years old, one of the few fossil myxomycetes, and the only definitive Mesozoic one. Six densely-arranged stalked sporocarps were engulfed in tree resin while young, with almost the entire spore mass still inside the sporotheca. All morphological features are indistinguishable from those of the modern, cosmopolitan genus Stemonitis, demonstrating that sporocarp morphology has been static since at least the mid-Cretaceous. The ability of myxomycetes to develop into dormant stages, which can last years, may account for the phenotypic stasis between living Stemonitis species and this fossil one, similar to the situation found in other organisms that have cryptobiosis. We also interpret Stemonitis morphological stasis as evidence of strong environmental selection favouring the maintenance of adaptations that promote wind dispersal.Peer reviewe

NMR Investigation and Conformational Analysis of a Synthetic Hexasaccharide

The structure of the hexasaccharide 1 has been examined by a spectroscopic investigation using one- and two-dimensional NMR spectroscopy. All 1H and 13C signals of the saccharide part were assigned. NOESY and ROESY experiments allowed to discuss the flexibility of the molecule

One Market, One Law: EU Enlargement in light of the economic theory of optimal legal areas

Drawing on a new analytical framework provided by the economic theory of optimal legal areas, this paper identifies the factors determining the optimal size of the European Union. It applies this theory to the question of how enlargement affects the welfare of the current and the new members of the European Union as well as that of the non-qualified countries. A welfare analysis reveals that enlargement can be a pareto-superior move. But, it also shows that enlargement can impose a negative externality on those countries left behind. In this case the results of a Kaldor-Hicks test are mixed. Furthermore, it is shown that the enlargement decision of the Union is unlikely to maximize overall welfare

Sareomycetes cl. nov. : A new proposal for placement of the resinicolous genus Sarea (Ascomycota, Pezizomycotina)

Resinicolous fungi constitute a heterogeneous assemblage of fungi that live on fresh and solidified plant resins. The genus Sarea includes, according to current knowledge, two species, S. resinae and S. difformis. In contrast to other resinicolous discomycetes, which are placed in genera also including non-resinicolous species, Sarea species only ever fruit on resin. The taxonomic classification of Sarea has proven to be difficult and currently the genus, provisionally and based only on morphological features, has been assigned to the Trapeliales (Lecanoromycetes). In contrast, molecular studies have noted a possible affinity to the Leotiomycetes. Here we review the taxonomic placement of Sarea using sequence data from seven phylogenetically informative DNA regions including ribosomal (ITS, nucSSU, mtSSU, nucLSU) and protein-coding (rpb1, rpb2, mcm7) regions. We combined available and new sequence data with sequences from major Pezizomycotina classes, especially Lecanoromycetes and Leotiomycetes, and assembled three different taxon samplings in order to place the genus Sarea within the Pezizomycotina. Based on our data, none of the applied phylogenetic approaches (Bayesian Inference, Maximum Likelihood and Maximum Parsimony) supported the placement of Sarea in the Trapeliales or any other order in the Lecanoromycetes. A placement of Sarea within the Leotiomycetes is similarly unsupported. Based on our data, Sarea forms an isolated and highly supported phylogenetic lineage within the "Leotiomyceta". From the results of our multilocus phylogenetic analyses we propose here a new class, order, and family, Sareomycetes, Sareales and Sareaceae in the Ascomycota to accommodate the genus Sarea. The genetic variability within the newly proposed class suggests that it is a larger group that requires further infrageneric classification.Peer reviewe

Crustose lichens with lichenicolous fungi from Paleogene amber

Lichens, symbiotic consortia of lichen-forming fungi and their photosynthetic partners have long had an extremely poor fossil record. However, recently over 150 new lichens were identified from European Paleogene amber and here we analyse crustose lichens from the new material. Three fossil lichens belong to the extant genus Ochrolechia (Ochrolechiaceae, Lecanoromycetes) and one fossil has conidiomata similar to those produced by modern fungi of the order Arthoniales (Arthoniomycetes). Intriguingly, two fossil Ochrolechia specimens host lichenicolous fungi of the genus Lichenostigma (Lichenostigmatales, Arthoniomycetes). This confirms that both Ochrolechia and Lichenostigma already diversified in the Paleogene and demonstrates that also the specific association between the fungi had evolved by then. The new fossils provide a minimum age constraint for both genera at 34 million years (uppermost Eocene).Peer reviewe

A microworld in Triassic amber

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The sporophyte of the Paleogene liverwort Frullania varians Caspary

We document the sporophyte of the extinct Frullania varians based on an inclusion in Late Oligocene Bitterfeld amber from Germany. The sporophyte consists of a short, ca. 45 µm thick seta that exceeds the perianth only slightly; the elongate-ovate, acute valves of the opened capsule are about 225 µm long, curved backwards and consist of an epidermal and an internal layer. Cell walls of both layers possess nodulose trigones. Several trumpet-shaped, unispiral elaters are fixed to the upper third of the internal valve layer. They have a length of ca. 150 µm and a diameter of 15–18 µm. A subglobose structure of 19 µm diameter is interpreted as a degraded spore. Fossil elaters and spores as well as capsule wall details of Frullaniaceae are described for the first time.doi:10.1002/mmng.20120000