245 research outputs found

    New Early Cretaceous weevil taxa from Spain (Coleoptera, Curculionoidea)

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    New genera Distenorrhinoides (type species D. simulator n.sp.) and Microbrenthorrhinus (type species M. martinezi n.sp.) (Nemonychidae, Brenthorrhininae) are described as well as the new species Brenthorrhinoides lacasai (Nemponychidae), Gobicar hispanicus and Cretonanophyes rugosithorax ( Eccoptarthridae)

    An Early Jurassic insect fauna in the Holy Cross Mountains

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    This note reports on a new locality of Early Jurassic insects in Poland and offers a preliminary list of its entomofauna

    New Early Cretaceous weevil taxa from Spain (Coleoptera, Curculionoidea)

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    New genera Distenorrhinoides (type species D. simulator n.sp.) and Microbrenthorrhinus (type species M. martinezi n.sp.) (Nemonychidae, Brenthorrhininae) are described as well as the new species Brenthorrhinoides lacasai (Nemponychidae), Gobicar hispanicus and Cretonanophyes rugosithorax ( Eccoptarthridae).New genera Distenorrhinoides (type species D. simulator n.sp.) and Microbrenthorrhinus (type species M. martinezi n.sp.) (Nemonychidae, Brenthorrhininae) are described as well as the new species Brenthorrhinoides lacasai (Nemponychidae), Gobicar hispanicus and Cretonanophyes rugosithorax ( Eccoptarthridae)

    Relief and geology of the north polar region of the planet Venus

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    Description of topographic features is given for the North polar region of the planet Venus. Principal geomorphic types of terrain are characterized as well as their geologic relations. Relative ages of geologic units in Venus North polar region are discussed

    Coherence Enhanced Transient Lasing in XUV Regime

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    We report the effect of a coherent drive on transient lasing in three-level Λ\Lambda and Ξ\Xi configurations (cabc\leftrightarrow a\leftrightarrow b). We show that the presence of a resonant coherent drive on the aca\leftrightarrow c optical transition can yield an order of magnitude enhancement of the output laser energy on a aba\rightarrow b XUV or X-ray transition than with no coherent drive. We demonstrate the crucial role of coherence ϱac\varrho_{ac} for the laser power enhancement. Contrary to the forward direction (with respect to the pump), where forward gain can be enhanced for some choice of the drive Rabi frequency Ωc\Omega_{c}, coherent drive on the acac transition always suppresses the backward gain.Comment: 8 pages, 11 figure

    Hyptiogastrites electrinus Cockerell, 1917, from Myanmar (Burmese) amber: Redescription and its placement within the Evanioidea (Insecta: Hymenoptera)

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    © The Natural History MuseumThe wasp Hyptiogastrites electrinus Cockerell, 1917, from the Lower Cretaceous (Upper Albian) Myanmar (Burmese) amber is redescribed from the well-preserved holotype and its relationship with extant Aulacidae and Gasteruptiidae (Hymenoptera: Evanioidea) evaluated. Although the wing venation is identical to the majority of extant Hyptiogastrinae (Gasteruptiidae), phylogenetic analysis places H. electrinus as sister taxon to the Aulacidae s.str., (i.e. Aulacus + Pristaulacus). Thus, Hyptiogastrinae is confirmed as having a restricted Southern Hemisphere distribution (i.e. Australasia and South America). Consistent with this result, H. electrinus is included within a slightly more broadly defined Aulacidae rather than being placed in a new monotypic family. Characters that align this species with the Aulacidae include: having small circular eyes, percurrent Y-shaped notauli, pyramidal shape of the propodeum and the presence of a groove or ovipositor guide on the hind coxae.John T. Jennings, Andrew D. Austin and Nicholas B. Steven

    Molecular evolution of cyclin proteins in animals and fungi

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    <p>Abstract</p> <p>Background</p> <p>The passage through the cell cycle is controlled by complexes of cyclins, the regulatory units, with cyclin-dependent kinases, the catalytic units. It is also known that cyclins form several families, which differ considerably in primary structure from one eukaryotic organism to another. Despite these lines of evidence, the relationship between the evolution of cyclins and their function is an open issue. Here we present the results of our study on the molecular evolution of A-, B-, D-, E-type cyclin proteins in animals and fungi.</p> <p>Results</p> <p>We constructed phylogenetic trees for these proteins, their ancestral sequences and analyzed patterns of amino acid replacements. The analysis of infrequently fixed atypical amino acid replacements in cyclins evidenced that accelerated evolution proceeded predominantly during paralog duplication or after it in animals and fungi and that it was related to aromorphic changes in animals. It was shown also that evolutionary flexibility of cyclin function may be provided by consequential reorganization of regions on protein surface remote from CDK binding sites in animal and fungal cyclins and by functional differentiation of paralogous cyclins formed in animal evolution.</p> <p>Conclusions</p> <p>The results suggested that changes in the number and/or nature of cyclin-binding proteins may underlie the evolutionary role of the alterations in the molecular structure of cyclins and their involvement in diverse molecular-genetic events.</p

    Changes to the Fossil Record of Insects through Fifteen Years of Discovery

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    The first and last occurrences of hexapod families in the fossil record are compiled from publications up to end-2009. The major features of these data are compared with those of previous datasets (1993 and 1994). About a third of families (>400) are new to the fossil record since 1994, over half of the earlier, existing families have experienced changes in their known stratigraphic range and only about ten percent have unchanged ranges. Despite these significant additions to knowledge, the broad pattern of described richness through time remains similar, with described richness increasing steadily through geological history and a shift in dominant taxa, from Palaeoptera and Polyneoptera to Paraneoptera and Holometabola, after the Palaeozoic. However, after detrending, described richness is not well correlated with the earlier datasets, indicating significant changes in shorter-term patterns. There is reduced Palaeozoic richness, peaking at a different time, and a less pronounced Permian decline. A pronounced Triassic peak and decline is shown, and the plateau from the mid Early Cretaceous to the end of the period remains, albeit at substantially higher richness compared to earlier datasets. Origination and extinction rates are broadly similar to before, with a broad decline in both through time but episodic peaks, including end-Permian turnover. Origination more consistently exceeds extinction compared to previous datasets and exceptions are mainly in the Palaeozoic. These changes suggest that some inferences about causal mechanisms in insect macroevolution are likely to differ as well
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