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Multi-scale Mineralogical Characterization of the Mediterranean Hypercalcified Sponge Petrobiona massiliana (Porifera, Calcarea, Calcaronea)
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The massive basal skeleton of a few remnant living hypercalcified sponges rediscovered since the 1960s are valuable representatives of ancient calcium carbonate biomineralization mechanisms in basal Metazoa. A multi-scale mineralogical characterization of the easily accessible Mediterranean living hypercalcified sponge belonging to Calcarea, Petrobiona massiliana (Vacelet and Lévi, 1958), was conducted. Oriented observations in light and electron microscopy of mature and growing areas of the Mg-calcite basal skeleton were combined in order to describe all structural levels from the submicronic to the macroscopic scale. The smallest units produced are ca. 50–100 nm grains that are in a mushy amorphous state before their crystallization. Selected area electron diffraction (SAED) further demonstrated that submicronic grains are assembled into crystallographically coherent clusters or fibers, the latter are even laterally associated into single-crystal bundles. A model of crystallization propagation through amorphous submicronic granular units is proposed to explain the formation of coherent micron-scale structural units. Finally, XRD and EELS analyses highlighted, respectively, inter-individual variation of skeletal Mg contents and heterogeneous spatial distribution of Ca ions in skeletal fibers. All mineralogical features presented here cannot be explained by classical inorganic crystallization principles in super-saturated solutions, but rather underlined a highly biologically regulated formation of the basal skeleton. This study extending recent observations on corals, mollusk and echinoderms confirms that occurrence of submicronic granular units and a possible transient amorphous precursor phase in calcium carbonate skeletons is a common biomineralization strategy already selected by basal metazoans.
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RBINS Staff Publications
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Multi-stage evolution of the monzonitic Larvik Plutonic Complex (Oslo Rift, Norway) and its implications for the formation of the Kodal Fe-Ti-P (− REE) deposit
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RBINS Staff Publications 2024
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Multimodal defensive strategies in larvae of two Hemichroa sawfly species
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RBINS Staff Publications
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Multimodality of a particle size distribution of cohesive suspended particulate matters in a coastal zone
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Particle size distributions (PSDs) of suspended particulate matters in a coastal zone are lognormal and multimodal in general. The multimodal PSD, which is caused by the mixing of multiple particle and aggregate size groups under flocculation and erosion/resuspension, is a record of the particle and aggregate dynamics in a coastal zone. Curve-fitting software was used to decompose the multimodal PSD into subordinate lognormal PSDs of primary particles, flocculi, microflocs, and macroflocs. The curve-fitting analysis for a time series of multimodal PSDs in the Belgian coastal zone showed the dependency of the multimodality on (1) shear-dependent flocculation in a flood and ebb tide, (2) breakage-resistant flocculation in the spring season, and (3) silt-sized particle erosion and advection in a storm surge. Also, for modeling and simulation purposes, the curve-fitting analysis and the settling flux estimation for the multimodal PSDs showed the possibility of using discrete groups of primary particles, flocculi, microflocs, and macroflocs as an approximation of a continuous multimodal PSD.
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Multiple dating approach (14C, 230Th/U and 36Cl) of tsunami-transported reef-top boulders on Bonaire (Leeward Antilles) – Current achievements and challenges
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RBINS Staff Publications 2018
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Multiple genetic species in a halophilic non-marine ostracod (Crustacea)
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The discovery of animal genetic (mostly also cryptic) species has known an exponential increase since molecular techniques became available. Also in non-marine ostracods (small, bivalved crustaceans with an excellent fossil record), several morphospecies have been shown to comprise several genetic species. Here, we screen 13 populations from Central Europe and the circum-Mediterranean region of the halophilic continental ostracod species Heterocypris salina with DNA sequences from a mitochondrial (COI) and a nuclear (28S) marker. We apply four species delimitation methods to show that this nominal species consists of four genetic species in both DNA datasets, and that these two sets of genetic species show mitonuclear discordance. Most investigated specimens belonged to one of these four genetic species. There was no clear correlation between geographic and genetic distances, but we found that, apart from historical processes, environmental factors such as ecoregion, seasonality and salinity might have been important drivers shaping discrete genetic diversity. Following the palaeontological literature, the H. salina species cluster is at least 11–9 Myr old.
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RBINS Staff Publications 2024
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Multiple oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)
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RBINS Staff Publications 2017
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Multiples oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)
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RBINS Staff Publications 2017
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Multituberculate mammal of possible North American affinity in the Maastrichtian of the Russian Far East
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RBINS Staff Publications 2025 OA
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Mystacodon selenensis, the earliest known toothed mysticete (Cetacea, Mammalia) from the late Eocene of Peru: anatomy, phylogeny, and feeding adaptations
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RBINS Staff Publications 2019
