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Diacodexis gigasei n. sp., le plus ancien Artiodactyle (Mammalia) belge, proche de la limite Paléocène-Eocène
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Les données acquises au cours de fouilles récentes ainsi que la mise en commun du matériel de plusieurs collections du gisement de Dormaal (localitt de référence du Niveau-Repère MP 7) ont permis de rassembler une douzaine de dents jugales de Diacodrxis. L'étude de ce matériel et sa comparaison avec diverses espèces primitives de Diacodrxis de I'Eocène inftrieur d'Europe, d'Amtrique du Nord et d'Asie ont permis de définir la nouvelle espèce, Diacodexis gigasri. Une position phylogénttique est proposée pour cette nouvelle espèce.
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Macrocranion germonprae n. sp., insectivore proche de la limite Paléocène-Eocène en Belgique
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La nouvelle espèce Macrocranion germonpreae du Membre de Dormaal (Groupe de Landen, Belgique) est décrite sur la base de dents jugales isolées. Cet insectivore érinacéomorphe est comparé aux autres espèces du genre Macrocranion d'Europe et d'AmCrique du Nord. M. germonpreae possède les caractères morphologiques d'un Dormaaliinae primitif.
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A new species of Kriptobaatar (Multituberculata): the first Late Cretaceous mammal from Inner Mongolia (P.R. China)
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Multituberculates are the best represented mammals of the Late Cretaceous in Asia and most of them are from Outer Mongolia. The djadochtatherioidean multituberculate Kr)ptobaut~im- andihuensis n. sp. is described on the basis of two skulls froin the Upper Cretaccous localiiy of Bayan Mandaliu (Inner Mongolia, People's Republic of China). The main characters that differentiate it from tlie type species K. dashzevegi Kielan-Jaworowska, 1970 are: the base of the zygomatic arch situated at the level of tlie anterior root of the P4 and the narrow anterior extent of the orbit, the "V" shape of the palatoinaxillary suture between the tlvo major palatine fonmina, the high and thick part of the dentary under the mandibular diastema. the long and low part of the dentary iinder the mandibular notch, the anteroposteriorly short coronoid process. the presence of 5 cusps on the middle row of Ml and on the labial row of ml, the long p4. the Iiigh ratio p4:ml length, and the robust il. The presence of this species in lnner Mongolia extends the palacogeographical distribution area of the djadochtatherioideans to the soutliern part of the Gobi Basin. Neveiiheless, morphological differences between K. tnandahitensis from lnner Mongolia and K. dushzevegi from Outer Mongolia suggest a palaeogeographical isolation within the Djadochtatherioidea group during the Campanian.
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Differentiation between two salt marsh beetle ecotypes: Evidence for ongoing speciation
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The plausibility of trait divergence under divergent natural selection in the presence of gene flow in natural populations is a contentious issue in evolutionary research. Its importance lies in the fact that this process is thought to be one of the key triggers in ecological speciation in which a species splits into ecologically distinct forms when separate niches are occupied. in this study we demonstrate strong genetic divergence at the IDH1 locus between pond- and canal-inhabiting individuals of the salt marsh beetle Pogonus chalceus from the Guerande salt fields. Moreover, wing size, a trait that has a heritable basis in this species, was significantly larger in the pond populations, which is in concordance with the unstable nature of this habitat. The relationship between IDH1 allele frequencies and wing size variation was consistent with patterns seen across western European populations. By means of neutral allozymes and microsatellites we detected a small but significant degree of sexual isolation between ecotypes. We conclude that speciation is ongoing and that divergence reflects a balance between selection and gene flow.
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Experimental exposure to cadmium affects metallothionein-like protein levels but not survival and growth in wolf spiders from polluted and reference populations
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Both local adaptation and acclimation in tolerance mechanisms may allow populations to persist under metal pollution. However, both mechanisms are presumed to incur (energetic) costs and to trade-off with other life-history traits. To test this hypothesis, we exposed Pardosa saltans (Lycosidae) spiderlings originating from metal-polluted and unpolluted sites to a controlled cadmium (Cd) treatment, and compared contents of metal-binding metallothionein-like proteins (MTLPs), internal metal concentrations, and individual survival and growth rates with a reference treatment. While increased MTLP concentrations in offspring originating from both polluted and unpolluted populations upon exposure indicates a plastic tolerance mechanism, survival and growth rates remain largely unaffected, independent of the population of origin. However, MTLP and Cd concentrations were not significantly correlated. We suggest that MTLP production may be an important mechanism enabling P. saltans populations to persist in ecosystems polluted with heavy metals above a certain level. (C) 2010 Elsevier Ltd. All rights reserved.
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Human-Induced Expanded Distribution of Anopheles plumbeus, Experimental Vector of West Nile Virus and a Potential Vector of Human Malaria in Belgium
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For the majority of native species, human-created habitats provide a hostile environment that prevents their colonization. However, if the conditions encountered in this novel environment are part of the fundamental niche of a particular species, these low competitive environments may allow strong population expansion of even rare and stenotopic species. If these species are potentially harmful to humans, such anthropogenic habitat alterations may impose strong risks for human health. Here, we report on a recent and severe outbreak of the viciously biting and day-active mosquito Anopheles plumbeus Stephens, 1828, that is caused by a habitat shift toward human-created habitats. Although historic data indicate that the species was previously reported to be rare in Belgium and confined to natural forest habitats, more recent data indicate a strong population expansion all over Belgium and severe nuisance at a local scale. We show that these outbreaks can be explained by a recent larval habitat shift of this species from tree-holes in forests to large manure collecting pits of abandoned and uncleaned pig stables. Further surveys of the colonization and detection of other potential larval breeding places of this mosquito in this artificial environment are of particular importance for human health because the species is known as a experimental vector of West Nile virus and a potential vector of human malaria.
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Hydrological regime and salinity alter the bioavailability of Cu and Zn in wetlands
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In the context of the European Water Framework Directive, controlled flooding of lowlands is considered as a potential water management strategy to minimise the risk of flooding of inhabited areas. However, due to historical pollution and overbank sedimentation, metal levels are elevated in most wetlands, which can cause adverse effects on the ecosystem's dynamics. Additionally, salinity affects the bioavailability of metals present or imported into these systems. The effect of different flooding regimes and salinity exposure scenarios (fresh- and brackish water conditions) on Cu and Zn accumulation in the oligochaete Tubifex tubifex (Muller, 1774) was examined. Metal mobility was closely linked to redox potential, which is directly related to the prevalent hydrological regime. Flooded, and thus more reduced, conditions minimized the availability of metals, while oxidation of the substrates during a drier period was associated with a rapid increase of metal availability and accumulation in the oligochaetes. (C) 2009 Elsevier Ltd. All rights reserved.
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Loss of genetic diversity and increased genetic structuring in response to forest area reduction in a ground dwelling insect: a case study of the flightless carabid beetle Carabus problematicus (Coleoptera: Carabidae)
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Site Fidelity of Formica rufa: Micro-Scaled and Persistent Despite Disturbance (Hymenoptera: Formicidae)
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Long-term site fidelity or Ortstreue is an individual foraging strategy typical of ants exploiting stable and predictable food sources in space and time. Red wood ant workers (Formica s. str.) are central-place foragers feeding on honeydew secreted by stable aphid populations. In this field study, temporal site fidelity of Formica rufa honeydew tenders was investigated on a micro-scaled level for a period of time. Additionally, the effect of exchanging honeydew workers between two trees on site fidelity was examined. Site fidelity of the honeydew tenders was very high and they returned repeatedly to particular micro-sites (branches, set of leaves) on a tree. The transfer to a new feeding site apparently did not influence site fidelity as honeydew tenders mainly return to their initial tree. Small-scale site fidelity decreased with time and was not so rigid as larger-scale fidelity. We discuss how site fidelity on one hand and flexibility in foraging and recruiting on the other hand promote foraging efficiency of the colony.
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The boundary between the Middle Eocene Brussel Sand and the Lede Sand Formations in the Zaventem-Nederokkerzeel area (Northeast of Brussels, Belgium).
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