Search publications of the members of the Royal Belgian institute of natural Sciences
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Practical key to identify entire edible insects sold as foodstuff or feedstuff in central Europe
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Delafossite structure of heterogenite polytypes (HCoO2) by Raman and infrared micro-spectroscopy
- Heterogenite is commonly referred in mineralogy literature as a cobalt oxy-hydroxide CoO(OH). However, detailed analysis of Raman and infrared spectra acquired on particularly well-crystallized natural samples of heterogenite suggests that the mineral can be characterized by a delafossite-type structure, with a general chemical formula ABO2. Indeed, the Raman spectrum of heterogenite, along the one with grimaldiite (HCrO2), lacks visible free OH-group vibrational modes, while the infrared spectrum shows strong hydrogen bond absorption bands. HCoO2 is thus a better formulation of heterogenite that describes more clearly its vibrational behavior and avoids the confusion in literature. Electronic backscattered diffraction (EBSD) is then used to distinguish and map the 2H and 3R heterogenite natural polytypes for the first time. The comparison of EBSD and Raman mappings clearly indicates that the 2H polytype is characterized by an additional peak at 1220 cm− 1. It's presence/absence is therefore an efficient tool to distinguish both polytypes.
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Manganese layered oxides (asbolane, lithipophorite and intermediates) identification and characterization by Raman and infrared spectroscopy
- In this study, Raman and infrared spectroscopy is applied to investigate two manganese oxide phases: lithiophorite [(Al,Li)Mn4+O2(OH)2] and asbolane [(Ni,Co)xMn4+(O,OH)4.nH2O], along with their intermediates (“Asbolane-Lithiophorite Intermediates”: ALI). These oxides typically incorporate variable concentrations of Co, Ni, Cu and Li. They represent a group of economically interesting phases that are difficult to identify and characterize with classical X-ray diffraction techniques. They were described in many places around the world, including the oxidized horizon of large ore deposits in New-Caledonia, Australia, the Democratic Republic of the Congo (DRC) amongst others. They also represents phases encountered as Ni-Co enriched manganese nodules of the deep ocean floors. Our results show that Lithium-bearing manganese oxides with typical X-ray diffraction lines of lithiophorite can exhibit two different Raman responses, namely the one of a typical lithiophorite and the one of ALI. This difference of reaction between X-ray and Raman methods strengthen the model developed in literature [2] that the X-ray diffraction lines of these oxides result primarily from one component of the structure, the MnO6 octahedra layers. In the same way, the reflectors associated with the unstructured Ni-Co oxide layers in asbolane are too weak to be visible on X-ray diffraction patterns. By contrast, the Raman responses are also driven by the chemical composition of the samples, allowing a more precise characterization. We propose reference Raman spectroscopic signatures for lithiophorite, asbolane and ALI phases. These spectra are mainly composed of two spectral domains, the first one is located between 370-630 cm-1 and the second one between 900-1300 cm-1. We then assess the impact of their highly variable chemistry on their Raman peak positions, intensities and FWHM using a semi-systematic curve-fitting method profiled for these phases. The strong affinities observed between the Raman spectral content of asbolane, lithiophorite and their intermediates, combined with the progressive trend observed for some peak parameters indicate that the studied phases represent probably a solid solution.
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Aerial imagery from an high-altitude drifting balloon platform : applications in geohazards monitoring (Sierra Arana, Spain and Mons Province, Belgium)
- A new type of untethered balloon based mapping platform allows affordable remote sensing applications from higher altitudes and with a greater range and payload capacity than common motorized UAV’s. The airborne device, called « Stratochip » is based on a dual helium balloons configuration. At a defined altitude (comprised between 500 and 30000m), the first balloon is released, drastically reducing the platform climbing rate. The payload (up to 10kg) can then drift in a sub-horizontal trajectory until it leaves a pre-defined area of interest. Leaving the pre-defined area, the second balloon is released and the payload is recovered after a parachute landing. The predicted flight path of the Stratochip, launch site and surveyed area are calculated using both forecasted (NOAA model) and real-time (inborne instruments) meteorological data, along with the physical parameters of the balloons and parachute. The predicted recovery area can also be refined in real-time to secure and facilitate equipment retrieval. In this study, we present the results of two cartographic campaigns made in Belgium (Ground collapse near Mons) and Spain (karstic field in the Eastern part of Sierra Arana, Granada region). Those campaigns aimed to test the usability of the Stratochip to survey a large area (up to 900km² for Spain) at medium and low altitudes (8000m - 500m) and produce an updated Digital Elevation Model and orthophoto mosaic of those regions. For that purpose, the instrument installed in the Stratochip payload was constituted of a digital camera stabilized with two IMU’s and two brushless motors. An automated routine then tilted the camera at predefined angles while taking pictures of the ground. This technique allowed to maximize the photogrammetric information collected on a single pass flight, and improved the DEM reconstruction quality, using structure-from-motion algorithms. The quality of produced DEM were then evaluated by comparing the level and accuracy of details and surface artefacts between available topographic data (LIDAR, SRTM, topographic maps) and the Stratochip sets. This evaluation showed that the models were in good correlation with existing data, and can be readily be used in geomorphology, structural and natural hazard studies.
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Contrubution to the knowledge of Afrotropical Rutelinae IV (Coleoptera: Scarabaeoidea: Melolonthidae)
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New carnivoraforms from the Latest Paleocene of Europe and their bearing on the origin and radiation of Carnivoraformes (Carnivoramorpha, Mammalia)
- We report the discovery of the earliest European carnivoraforms, based on two new taxa from the latest Paleocene of France and Romania. A new species of Vassacyon, V. prieuri, from the locality of Rivecourt (MP6b; Oise, France) (MP D Mammalian Paleogene reference levels) is described based on a dentary fragment and isolated teeth. This species displays several primitive features compared with species of Vassacyon known from the early Eocene of North America and Europe. A second Paleocene carnivoraform, cf. Gracilocyon sp., is described based on fragmentary specimens from the locality of Jibou (MP6b; Transylvania, Romania). Carnivoraformes were previously unknown in Europe before the Eocene, and Vassacyon prieuri and cf. Gracilocyon sp. are their oldest records in Europe. These discoveries favor the hypothesis of a dispersal of these two genera from Europe to North America during the Paleocene-Eocene Thermal Maximum. Vassacyon prieuri and cf. Gracilocyon sp. strengthen support for the level MP6b and its correlation with the Clarkforkian. The geographic origin of the Carnivoraformes remains unknown. However, based on the observed biochronological and geographic distributions of the carnivoraforms, we infer a possible Asian origin for this group. In this scenario, Gracilocyon and Vassacyon dispersed to Europe during the Clarkforkian MP6b time, probably together with rodent taxa, whereas Uintacyon dispersed from Asia to North America shortly after rodents and tillodonts
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Compte rendu de l'assemblée générale du 30 octobre 2015
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First insights into the diversity of gill monogeneans of ‘Gnathochromis’ and Limnochromis (Teleostei, Cichlidae) in Burundi: do the parasites mirror host ecology and phylogenetic history?
- Monogenea is one of the most species-rich groups of parasitic flatworms worldwide, with many species described only recently, which is particularly true for African monogeneans. For example, Cichlidogyrus, a genus mostly occurring on African cichlids, comprises more than 100 nominal species. Twenty-two of these have been described from Lake Tanganyika, a famous biodiversity hotspot in which many vertebrate and invertebrate taxa, including monogeneans, underwent unique and spectacular radiations. Given their often high degrees of host specificity, parasitic monogeneans were also used as a potential tool to uncover host species relationships. This study presents the first investigation of the monogenean fauna occurring on the gills of endemic ‘Gnathochromis’ species along the Burundese coastline of Lake Tanganyika. We test whether their monogenean fauna reflects the different phylogenetic position and ecological niche of ‘Gnathochromis’ pfefferi and Gnathochromis permaxillaris. Worms collected from specimens of Limnochromis auritus, a cichlid belonging to the same cichlid tribe as G. permaxillaris, were used for comparison. Morphological as well as genetic characterisation was used for parasite identification. In total, all 73 Cichlidogyrus individuals collected from ‘G.’ pfefferi were identified as C. irenae. This is the only representative of Cichlidogyrus previously described from ‘G.’ pfefferi, its type host. Gnathochromis permaxillaris is infected by a species of Cichlidogyrus morphologically very similar to C. gillardinae. The monogenean species collected from L. auritus is considered as new for science, but sample size was insufficient for a formal description. Our results confirm previous suggestions that ‘G.’ pfefferi as a good disperser is infected by a single monogenean species across the entire Lake Tanganyika. Although G. permaxillaris and L. auritus are placed in the same tribe, Cichlidogyrus sp. occurring on G. permaxillaris is morphologically more similar to C. irenae from ‘G.’ pfefferi, than to the Cichlidogyrus species found on L. auritus. Various evolutionary processes, such as host-switching or duplication events, might underlie the pattern observed in this particular parasite-host system. Additional samples for the Cichlidogyrus species occuring on G. permaxillaris and L. auritus are needed to unravel their evolutionary history by means of (co-)phylogenetic analyses.
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A 365-Million-Year-Old Freshwater Community Reveals Morphological and Ecological Stasis in Branchiopod Crustaceans
- Branchiopod crustaceans are represented by fairy, tadpole, and clam shrimps (Anostraca, Notostraca, Laevicaudata, Spinicaudata), which typically inhabit temporary freshwater bodies, and water fleas (Cladoceromorpha), which live in all kinds of freshwater and occasionally marine environments. The earliest branchiopods occur in the Cambrian, where they are represented by complete body fossils from Sweden such as Rehbachiella kinnekullensis and isolated mandibles preserved as small carbonaceous fossils from Canada. The earliest known continental branchiopods are associated with hot spring environments represented by the Early Devonian Rhynie Chert of Scotland (410 million years ago) and include possible stem-group or crown-group Anostraca, Notostraca, and clam shrimps or Cladoceromorpha, which differ morphologically from their modern counterparts. Here we report the discovery of an ephemeral pool branchiopod community from the 365-million-year-old Strud locality of Belgium. It is characterized by new anostracans and spinicaudatans, closely resembling extant species, and the earliest notostracan, Strudops goldenbergi. These branchiopods released resting eggs into the sediment in a manner similar to their modern representatives. We infer that this reproductive strategy was critical to overcoming environmental constraints such as seasonal desiccation imposed by living on land. The pioneer colonization of ephemeral freshwater pools by branchiopods in the Devonian was followed by remarkable ecological and morphological stasis that persists to the present day.
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Nouvelle contribution à l'étude du genre Autocrates Thomson, 1860 avec la description d'une nouvelle espèce du Vietnam: A. ivanovi n.sp. (Coleoptera: Trictenotomidae).
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Description de Patellapis (Chaetalictus- mpalaensis sp.nov. et redescription de P. (C.) virungae Timmerman, 2009 de l'Afrique orientale et centrale (Hymenoptera: Apoidea: Halictidae)
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Updating laternflies biodiversity knowledge in Cambodia (Hemiptera: Fulgoromorpha: Fulgoridae) by optimizing field work surveys with citizen science involvement through Facebook networking and data access in FLOW website
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Building a transnationally harmonised marine geological database
- Within the framework of marine resource management, a common knowledge base is being developed on the distribution, composition and dynamics of various geological resources. Focus is on data from the Belgian part of the North Sea, being representative of a typical sandbank sedimentary system. To ensure harmonised seabed mapping over large, supraregional areas and to facilitate the exchange of information, special attention was paid to compatibility with marine geodatabases from the adjacent Netherlands territory. With reference to the seabed and its subsurface, two main databases are being compiled: one comprising all available lithological descriptions and one with all numerical grain-size information. To enable standardisation of the data and make them easily query-able, non-numerical descriptions are being coded to an international standard (EU FP7 Geo-Seas; www.geoseas.eu), of which the Udden-Wentworth scale is the main classifier. Several other parameters were derived, such as percentages mud, sand, gravel, shells and organic material. For the sediment database, cumulative grain-size-distribution curves were compiled, enabling calculations of any desired granulometry parameter, such as percentages of the grain-size fractions (fine, medium, coarse sand) and percentiles that are relevant in seabed-habitat mapping or sediment-transport modelling (D35, D50, D84). For both databases, the completeness and accuracy of the metadata were considered highly important. Information about sampling and coring techniques, analytical methods, horizontal and vertical positioning accuracy, and the exact timing of data acquisition is pivotal in uncertainty analyses, which are an increasingly important element of seabed mapping. The time of seabed mapping is critical to convert measured water depths to a common datum such as TAW in Belgium, facilitating integration of sample data in bathymetry data and thus their incorporation in 4D-modelling studies on morphodynamic change. For Belgium, the geological databases will be imbedded in the data infrastructure of the Belgian Marine Data Centre (www.bmdc.be), ensuring compatibility with international standards and providing easy access to a wide user community. Following processing to generate data products such as resource-related subsurface models, visualisation is foreseen through Subsurface Viewer (GmbH INSIGHT). Applied maps and models thus disseminated are crucial in decision making, and invaluable for outreach and educational purposes. The newly developed database and its associated data products will contribute to the objectives of the projects TILES (Belspo Brain-be), EMODnet-Geology (EU DG MARE), and ZAGRI (private revenues from the marine-aggregate industry).
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Transcription, signaling receptor activity, oxidative phosphorylation and fatty acid metabolism mediate the presence of closely-related cryptic species in distinct intertidal and cold-seep habitats
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Dynamics of very-large dunes in sandbank areas subjected to marine aggregate extraction, Belgian continental shelf
- Dynamics of very-large dunes were investigated over sandbanks subdued to marine aggregate extraction in the Belgian continental shelf. In the Flemish Banks, six areas were regularly monitored with a multibeam echosounder (MBES) providing high resolution bathymetric data. An optimization procedure was set up to estimate the dune migration distance and direction between successive campaigns. These dune migration data were compared to simulated hydrodynamic forces and indicated that dune migration was mostly driven by tidal currents, with the direction and magnitude of migration being dependent on the relative position of the dunes on the sandbanks. Closer investigation in a heavily extracted area suggested a local reorganization of sediments in the area: an accretional trend in the extraction pit is observed at the expense of the surrounding very-large dunes which presented an erosive and flattening pattern.
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Taxonomic challenges in freshwater fishes: a mismatch between morphology and DNA barcoding in fish of the north-eastern part of the Congo basin
- This study evaluates the utility of DNA barcoding to traditional morphology-based species identifications for the fish fauna of the north-eastern Congo basin. We compared DNA sequences (COI) of 821 samples from 206 morphologically identified species. Best match, best close match and all species barcoding analyses resulted in a rather low identification success of 87.5%, 84.5% and 64.1%, respectively. The ratio ‘nearest-neighbour distance/maximum intraspecific divergence’ was lower than 1 for 26.1% of the samples, indicating possible taxonomic problems. In ten genera, belonging to six families, the number of species inferred from mtDNA data exceeded the number of species identified using morphological features; and in four cases indications of possible synonymy were detected. Finally, the DNA barcodes confirmed previously known identification problems within certain genera of the Clariidae, Cyprinidae and Mormyridae. Our results underscore the large number of taxonomic problems lingering in the taxonomy of the fish fauna of the Congo basin and illustrate why DNA barcodes will contribute to future efforts to compile a reliable taxonomic inventory of the Congo basin fish fauna. Therefore, the obtained barcodes were deposited in the reference barcode library of the Barcode of Life Initiative.
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A new early Pliocene species of Mesoplodon: a calibration mark for the radiation of this species-rich beaked whale genus
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Comparative phylogeographies of six species of hinged terrapins (Pelusios spp.) reveal discordant patterns and unexpected differentiation in the P. castaneus/P. chapini complex and P. rhodesianus
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The new Oriental lanternfly genus £Bhaskaraena gen.nov. with two new species (Hemiptera: Fulgoromorpha: Fulgoridae)
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Fossil marine vertebrates of Cerro Los Quesos: Distribution of cetaceans, seals, crocodiles, seabirds, sharks, and bony fish in a late Miocene locality of the Pisco Basin, Peru
