44 research outputs found

    The taxonomic impediment: a shortage of taxonomists, not the lack of technical approaches

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    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

    Gallenblasenwanddicke bei nichtbiliären Erkrankungen

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    The Konservat-Lagerstätte Menat (Paleocene; France) – an overview and new insights

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    The Konservat-Lagerstätte Menat (Puy-de-Dôme, France) is an outstanding archive of a Paleocene ecosystem, which was deposited in a former maar lake. Excavations during the last century have yielded an extensive flora and fauna record, therefore an overview of the current state of paleontological investigations is given in this paper. Additionally, new results based on excavations from the years 2012 to 2014 are presented. The preservation of organic matter differed strongly between excavation sites, probably influenced by weathering processes. The stratigraphic succession consists mostly of organic-rich clays, intercalated with hard, silicified claystones. In 2013 and 2014 both impression and compression fossils were collected from different outcrops. Compression fossils from organic-rich clays were exceptionally well-preserved and included three-dimensional plant remains. A new database on insect paleobiodiversity was compiled. The occurrence of charcoal in almost all horizons investigated suggests that paleowildfires were frequent during the Paleocene in the vicinity of the paleolake. The results confirm the high potential of the Konservat-Lagerstätte Menat for future paleontological research
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