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Arthropod diversity in a tropical forest
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Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields 60\% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.
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Parallel phenotypic evolution in a wolf spider radiation on Galápagos.
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Within island archipelagos, repeated ecological settings may lead to radiations wherein similar niches are recurrently occupied. Although it has been shown that species with common habitat requirements share particular traits, it remains relatively unexplored to what extent this may lead to the repeated evolution of almost identical phenotypes (phenocopies) and how this correlates with traits subjected to sexual selection. Exploring divergence patterns of ecological and sexual relevant traits within spiders seem promising to enhance our understanding of the relative role of natural and sexual selection. Here, we conduct a detailed morphological analysis on a large set of genital and non-genital traits (morphometrics, colour pattern) within a radiation of the wolf spider genus Hogna Simon, 1885 on Galápagos and interpret these data, taking into account their known phylogenetic relationship. Our results show that recurrent environmental gradients have led to the parallel evolution of almost identical phenotypes, which not only proves that natural selection has driven morphological divergence, but also suggests that a similar genetic or developmental basis most likely underlies this divergence. Among-species variation in genital traits in contrast rather reflects the phylogenetic relationships on Santa Cruz and San Cristóbal. The combination of these data indicate that speciation in this system is driven by the combined effect of ecological mechanisms and allopatric divergence in sexual traits.
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Les élasmobranches de la transition Paléocène-Eocène de Dormaal (Belgique): implications biostratigraphiques et paléobiogéographiques
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The Dormaal Sands and the Palaeocene/Eocene boundary in Belgium
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Het archeologisch onderzoek in Raversijde (Oostende) in de periode 1992-2005
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Phytolith Evidence for the Early Presence of Domesticated Banana (Musa) in Africa
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Biologically-controlled mineralization in the hypercalcified sponge Petrobiona massiliana (Calcarea, Calcaronea)
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Hypercalcified sponges, endowed with a calcium carbonate basal skeleton in addition to their spicules, form one of the most basal metazoan group engaged in extensive biomineralization. The Mediterranean species Petrobiona massiliana was used to investigate biological controls exerted on the biomineralization of its basal skeleton. Scanning and transmission electron microscopy (SEM, TEM) confirmed that basopinacocytes form a discontinuous layer of flattened cells covering the skeleton and display ultrastructural features attesting intense secretory activity. The production of a highly structured fibrillar organic matrix framework by basopinacocytes toward the growing skeleton was highlighted both by potassium pyroantimonate and ruthenium red protocols, the latter further suggesting the presence of sulfated glycosaminoglycans in the matrix. Furthermore organic material incorporated into the basal skeleton was shown by SEM and TEM at different structural levels while its response to alcian blue and acridine orange staining might suggest a similar acidic and sulfated chemical composition in light microscopy. Potassium pyroantimonate revealed in TEM and energy electron loss spectroscopy (EELS) analysis, heavy linear precipitates 100–300 nm wide containing Ca2+ and Mg2+ ions, either along the basal cell membrane of basopinacocytes located toward the decalcified basal skeleton or around decalcified spicules in the mesohyl. Based on the results of the previous mineralogical characterization and the present work, an hypothetical model of biomineralization is proposed for P. massiliana: basopinacocytes would produce an extracellular organic framework that might guide the assemblage of submicronic amorphous Ca- and Mg-bearing grains into higher structural units.
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On the use of endosteal layers and medullary bone from domestic fowl in archaeozoological studies
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The very high incidence of medullary bone in two archaeozoological assemblages of the Roman period was believed to reflect systematic slaughtering of older hens at the end of the egg laying season. In an attempt to test this hypothesis, histological analyses were carried out. Histological data in the literature on ageing of modern fowl and on the development of medullary bone in hens are insufficient for application to archaeozoological material. Bones of modern fowl of known age were analysed with the aim of validating the use of endosteal layers for ageing. In addition, hens with known egg laying stage were studied in order to try and document differences in medullary bone development that could be related to the time of slaughtering (just before, during, or just after the egg laying season).
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An Industrial Site at al Shaykh Sa’id/Wadi Zabayda
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The status of the northeastern Atlantic and Mediterranean small mussel drills of the Ocinebrina aciculata complex (Mollusca: Gastropoda: Muricidae) with the description of a new species
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The northeastern Atlantic and Mediterranean small mussel drills of the Ocinebrina aciculata complex are here revised and consist of at least 3 species. The type species, Ocinebrina aciculata (Lamarck, 1822), characterized by a slender shell with rounded whorls and primary and secondary spiral cords of approximately similar size, lives throughout the northeastern Atlantic and Mediterranean Sea at depths usually ranging between 0 and 105 m. Its synonymy is here stabilized by a neotype selection for Murex corallinus Scacchi, 1836. Ocinebrina corallinoides Pallary, 1912 (=Ocinebrina buzzurroi Cecalupo and Mariani, 2008, new synonymy), characterized by a strongly elongate and weakly convex shell and primary and secondary spiral cords of approximately similar size, is endemic to the Gulf of Gabès and is here considered a distinct species, pending genetic studies. Ocinebrina reinai n. sp. is here described from the central Mediterranean Sea (where it is sympatric with O. aciculata) on the basis of morphological diagnostic features of shell (rarest presence of labral tooth, commoner presence of infrasutural apertural denticle, dark spots on the ribs and spiral sculpture with differently sized primary and secondary cords and smaller threads) and radula, confirmed by genetic data. Divergence in COI sequences with sympatric samples of O. aciculata (>7%), confirm their status as a distinct species. A comparative table reporting diagnostic features of the congeneric species of the complex and those with which the new species was previously misidentified is offered.
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