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Biodiversity of ostracod communities (Crustacea, Ostracoda) in a tropical floodplain
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Neotropical floodplains harbour both floating and rooted plants and are associated with rich ostracod communities. After dry seasons, flooding causes recruitment in 2 ways: floods bring in allochthonous macrophytes with associated pleuston communities, and these rising water levels rehydrate plants and attached (ostracod) eggs that dried at the onset of the dry season. We analysed the ostracods communities in the Araguaia River floodplain (Brazil) during 2 hydrological periods (dry and rainy) and evaluated the species distribution in relation to abiotic and biotic factors. We compared the ostracod fauna of 6 lakes in the dry and rainy period and 17 lakes in the rainy period. We tested the hypothesis that the highest values of ostracod community attributes (richness, density, and evenness) occur in the rainy season owing to the influx of allochthonous individuals and the rehydration of the dried autochthonous macrophytes. We indeed observed the highest richness and diversity of ostracods in the rainy season; the homogenizing effect of the flood pulse at the onset of the rainy season caused a more homogeneous fauna (lower beta diversity) during that hydrological period. The distribution of species showed a significant effect of both abiotic factors (local) and hydrological period (regional).
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RBINS Staff Publications 2017
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Biodiversity, Biogeography and Nature Conservation in Wallacea and New Guinea. Volume IV
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RBINS Staff Publications 2021
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Biogeographic atlas of the Southern Ocean
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RBINS Staff Publications
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Biogeographic patterns of Southern Ocean benthic Amphipods
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RBINS Staff Publications
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Biogeography and phylogeography of non-marine Ostracoda (Crustacea). Crustacean conference
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RBINS Staff Publications
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Biological and taxonomic perspective of triterpenoid glycosides of sea cucumbers of the family Holothuriidae (Echinodermata, Holothuroidea)
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RBINS Staff Publications
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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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Biology and fisheries of the spotted flounder (Citharus linguatula) caught by multiple gears with partial spatiotemporal overlaps
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Obtaining data to study fish biology can be a challenge if a stock is fished by a variety of gears with different effort units and different selectivity, particularly if these gears only partially overlap in space and time. In this work, we attempted to study the biology of the spotted flounder Citharus linguatula in the Patraikos Gulf and the adjacent central Ionian Sea (eastern Mediterranean) and to evaluate the current fisheries management. We characterized age composition and growth, length-at-maturity, and catch-perunit- effort (CPUE) of spotted flounder from the catches of bottom trawls, gillnets and trammel nets for the period autumn 2013–2014. Variation of fish total length, gonadosomatic index, hepatosomatic index and condition factor was analyzed using generalized additive models (GAMs) with regard to sex, date, fishing gear and depth.We also modeled CPUE fluctuations of each gear by date, depth, longitude and latitude using GAMs. Fish age ranged from 1 to 5 years. A slightly allometric growth was documented with females attaining larger sizes than males. Length-at-maturity was 163mm for females and 169mm for males. The seasonal change of gonad maturity stages and the gonadosomatic index indicated spawning in late summerautumn. Changes in length frequencies indicated that recruitment to the fisheries occurred in late springearly winter in shallow depth (<40 m). The catch composition of trawls and the CPUE model results suggested that the selectivity of this gear should be regulated to reduce catching immature individuals of spotted flounder. The results further indicated that the seasonal trawl closure of the Patraikos Gulf contributes to reduce catching juveniles.
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RBINS Staff Publications 2017
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Biomimetic and bio-inspired uses of mollusc shells
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RBINS Staff Publications 2016
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Biomineralization in living hypercalcified demosponges: Toward a universal mechanism?
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Massive skeletons of living hypercalcified sponges, representative organisms of basal Metazoa, are uncommon models to improve our knowledge on biomineralization mechanisms and their possible evolution through time. Eight living species belonging to various orders of Demospongiae were selected for a comparative mineralogical characterization of their aragonitic or calcitic massive basal skeleton. The latter was prepared for scanning and transmission electron microscopy (SEM and TEM), selected-area electron diffraction (SAED) and X-ray diffraction (XRD) analyses. SEM results indicated distinctive macro- and micro-structural organizations of the skeleton for each species, likely resulting from a genetically dictated variation in the control exerted on their formation. However, most skeletons investigated shared submicron to nano-scale morphological and crystallographical patterns: (1) single-crystal fibers and bundles were composed of 20 to 100nm large submicronic grains, the smallest structural units, (2) nano-scale likely organic material occurred both within and between these structural units, (3) {110} micro-twin planes were observed along aragonitic fibers, and (4) individual fibers or small bundles protruded from the external growing surface of skeletons. This comparative mineralogical study of phylogenetically distant species brings further evidence to recent biomineralization models already proposed for sponges, corals, mollusks, brachiopods and echinoderms and to the hypothesis of the universal and ancestral character of such mechanisms in Metazoa.
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