Search publications of the members of the Royal Belgian institute of natural Sciences
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L'intrusion de la Helle (Hautes-Fagnes, Belgique) et la minéralisation cupro-molybdenifère associée: synthèse bibliographique, données des sondages et interprétation globale
- The Helle intrusion is located in the eastern part of Belgium and was discovered by the end of last century. Geochronology (U-Pb isotopic ratios ofzircon) indicates that the magma emplacement took place between Silurian and Lower Devonian (minimum age of emplacement: around 381 ± 16 Ma). Previous studies have shown that the Helle intrusion is a sill structure with most of its outcropping rocks characterized by a petrographic composition of quartz-diorite (tonalite). The low degree of thermic metamorphism related to the intrusion is reflected by a very thin aureole of hornfels. The rather large zone of pyritic rocks surrounding the igneous rocks was probably generated by an extensive hydrothermal (mainly a sulphidization) episod possibly contemporary of the thermic metamorphism phase. Finally, a main episode of regional metamorphism contemporary of the variscan orogeny induced a metamorphism of low-grade (ACF : paragenesis prehnite-chlorite-epidote) in the igneous rocks of la Helle. In 1976-1977, at the initiative of Union Minière S.A., the concealed magmatic rocks were recognized by four drillings down to a depth of approximately 100 m. The Belgian Geological Survey supervised the study. Results are included in the present memoir divided into 3 parts. The first part is devoted to a bibliographic synthesis of the geology and the mineralization of the Helle area. In a second part, results of lithological and petrographical observations are presented. The study under the microscope emphasizes a large variation of petrographic composition ranging from diorites to granodiorites and monzodiorites. Mineralogic variations seem to be related to mechanisms of magmatic differentiation (mainly fractional crystallization) but also to a complex post-magmatic hydrothermal alteration process, which mainly affected the superficial area of the intrusion. That zone is characterized by a secondary K-feldspar occurrence. The hydrothermal alteration also produced silicification and partial albitization with the development of a network of veinlets (locally mineralized) in the magmatic and surrounding Revinian metaquartzopelitic rocks. In this part, lithogeochemical logs of metallic elements are shown. A three dimensional reconstruction of the intrusion indicates that the structure corresponds to a laccolitic sill-shaped of: ± 500 m of NE-SW length, 125 m of maximal thickness and 30° SE dip. Small dykes are also connected to the main sill. The third part concerns the petrological and metallogenical interpretations. The primary mineralization is mainly formed by sulphide components (chalcopyrite, bornite, molybdenite). The average Cu and Mo content of the igneous rock is low (Cu = 0,17 % ; Mo = 0,02 %). The low metal stock of the intrusion (Cu: ± 35 000 tons; Mo: ± 4 000 tons) is the consequence of a reduced volume of mineralized rock as weIl as common low metal contents. Metallogenically, this type of mineralization can be compared to the porphyry copper model although some important differences appear. The difficulty to distinguish the various concentric patterns of alteration suggests the smash of the alteration zones and is probably due to the small size of the intrusion. Résumé L'intrusion de la Helle, située dans l'Est de la Belgique (Hautes Fagnes), a été découverte à la fin du XIXème siècle. Des études antérieures ont établi qu'il s'agit d'un sill présentant une composition de diorite quartzique, ou, plus restrictivement, de tonalite. A cette intrusion, sont associés, d'une part un faible métamorphisme se traduisant par une ceinture pluridécimétrique de cornéennes et, d'autre part, un dynamométamorphisme caractérisé par une auréole plurihectométrique de schistes tachetés. En outre, une minéralisation cupro-molybdénifère est également présente. Une datation radiométrique par la méthode U-Pb sur zircon attribue à cette intrusion un âge minimum de mise en place vers 381 ± 16 Ma, c'est à dire silurien ou dévonien inférieur. Enfin, un métamorphisme régional contemporain de l'orogenèse varisque, a donné naissance à une paragenèse A CF (préhnite - chlorite - épidote) de faible degré. En 1976-1977, l'Union Minière a financé 4 sondages dans le but de préciser la forme de l'intrusion et son potentiel minier. Ils ont été confiés au Service géologique de Belgique qui en a supervisé l'étude dont les résultats sont présentés dans le présent mémoire divisé en 3 parties. Dans une première partie, on effectue une synthèse bibliographique sur la géologie et la minéralisation de la région de la Helle. Dans une deuxième partie, on présente les résultats des descriptions lithologiques détaillées et des observations pétrographiques consacrées aux sondages. Les observations diascopiques soulignent une importante variation de la composition minéralogique, caractérisée par une gamme de roches allant de la diorite à la diorite quartzique et de la monzodiorite à la granodiorite éventuellement quartzique. Les variations minéralogiques semblent associées à des mécanismes de différenciation magmatique (principalement la cristallisation fractionnée), mais aussi à un processus hydrothermal post-magmatique complexe qui a principalement affecté la partie superficielle de la colonne magmatique actuellement dégagée par l'érosion. Cette zone est marquée par l'occurrence de feldspath potassique. L'altération hydrothermale a également produit une silicification et une albitisation partielle avec développement d'un réseau de veinules/veines localement minéralisées dans la roche magmatique et l'encaissant quartzopélitique revinien. Dans cette partie, on précise également les variations lithogéochimiques des roches ignées pour les éléments métalliques et la géométrie en trois dimensions de l'intrusion. Il s'agit d'un silllaccolitique d'environ 500 m d'extension NE-SW, épais en son centre de 125 m maximum, plongeant à 30° vers le SE, duquel se dégagent des petits dykes. Une troisième partie est consacrée aux interprétations pétrologiques et métallogéniques. On peut établir un certain parallélisme qualitatif entre l'intrusion faiblement minéralisée de la Helle et un porphyre cuprifère classique. Bien qu'à la Helle, la plupart des zones d'altération hydrothermale soient mélangées et donc quasi indiscernables, la variation spatiale du feldspath potassique semble suggérer la présence d'un début d'altération potassique dans les secteurs périphériques de l'intrusion. Le télescopage des différentes zones d'altération est probablement du à la petite dimension de l'intrusion. Comme les teneurs sont également faibles (en moyenne: Cu = O,17 % ; Mo = 0,02 %), le stock métal estimé en première approximation (Cu: environ 35 000 tonnes; Mo: environ 4 000 tonnes) est également très modeste. Samenvatting De intrusie van de Helle, gelegen in het oosten van België (Hoge Venen), werd ontdekt op het einde van de XIXste eeuw. Vroegere studiën hebben aangetoond dat het om een sill gaat, met de samenstelling van kwartsdioriet of strikter genomen uit tonaliet. Aan deze intrusie is enerzijds een zwak metamorfisme geassocieerd dat zich vertaald door een gordel van verscheidene dm hoornrots, anderzijds een dynamometamorfisme, gekenmerkt door een aureool van verscheidene honderden m gedekte schisten. Daarnaast is eveneens een koper-molybdeen- mineralisatie aanwezig. Een radiometrische datering met de U-Pb-methode op zirkoon verleent die intrusie een minimum leeftijd van ontstaan rond 381 ± 16 Mj, d.w.z. Silurisch of Onder-Devoon. Tenslotte is door regionaal metamorfisme tijdens de varistische orogenese een zwake ACF-paragenese gevormd (prehniet-chloriet-epidoot). In 1976-1977, heeft Union Minière 4 boringen gefinancierd met de bedoeling de vorm van de intrusie en haar ontginbaarheid nauwkeurig te bepa1en. Ze werden toevertrouwd aan de Geologische Dienst van België die de studie begeleidde waarvan de resultaten voorgesteld worden in deze toelichtingen verdeeld in 3 delen. Een eerste deel bevat een bib1iographische synthese van de geologie en mineralisatie van de Hellestreek. Een tweede deel geeft de resultaten van de gedetailleerde lithologische beschrijvingen en de petrographische waarnemingen in de boringen. De diascopische waarnemingen wijzen op een belangrijke variatie van de mineralogische samenstelling, gekenmerkt door een gamma gesteenten gaande van dioriet naar kwartsdioriet en van monzodioriet naar eventueel kwartsgranodioriet. De mineralogische variaties blijken samen te gaan met magmatische differentiemechanismen (voornamelijk de gefractioneerde kristallisatie), maar ook met de ingewikkeld post-magmatisch hydrothermaal proces dat hoofdzakelijk heeft ingewerkt op het bovenste deel van de magmazui1 nu blootgelegd door erosie. Die zone wordt gekenmerkt door het voorkomen van ka1iumveldspaat. De hydrotherma1e verwering heeft eveneens geleid tot silicificatie en gedeeltelijke albitisatie, gepaard gaand met de vorming van een netwerk van gedeeltelijke aders/adertjes in het magmatische gesteente en de omgevende kwartsopelitische Reviniaan eenheden. In dit deel uiten zich ook duidelijk de lithogeochemische variaties van de stollingsgesteenten voor de metallische elementen en de driedimensionele geometrie van de intrusie. Het betreft een laccolitische sill met een omvang van ongeveer 500 m in de NO-ZW richting, in het midden maximum 125 m dik, 30° naar het ZO duikend, waarvan kleine dykes loskomen. Een derde deel is gewijd aan de petrologische en metallogenetische interpretaties. Men kan een zeker kwalitatief parallelisme vaststellen tussen de zwak gemineraliseerde intrusie van de Helle en een klassieke koperhoudende porfier. Hoewel in het geval van de Helle, de meeste hydrothermale verweringszones vermengd en dus vrijwel niet te onderscheiden zijn, blijkt de ruimtelijke variatie van kaliumveldspaat toch te wijzen op de aanwezigheid van een beginnende potassische verwering in de randzones van de intrusie. Het telescoperen van de verschillende verweringszones is waarschijnlijk toe te schrijven aan de geringe afmetingen van de intrusie. Daar de gehalten eveneens la ag zijn (gemiddeld : Cu = O,17%; Mo = 0,02%) wordt de metaalreserve in een eerste benadering (Cu ongeveer 35 000 ton; Mo: ongeveer 4000 ton) eveneens als zeer bescheiden aanzien.
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Le « Calcaire D’Etroeungt » dans les coupes historiques d’Etroeungt et d’Avesnelles (Avesnois, Nord, France).
- Le « Calcaire d’Etroeungt», extrême sommet du Famennien, reconnu historiquement par Gosselet, fait l’objet d’une représentation détaillée, avec positionnement des niveaux qui ont fourni des faunes, dans les coupes de la carrière du Parcq à Etroeungt, stratotype historique, et dans celle de la tranchée d’Avesnelles, proposée antérieurement comme parastratotype, car la série est incomplète dans la carrière du Parcq. Toutefois la recherche d’un nouveau parastratotype est indispensable car la limite supérieure est masquée dans la coupe de la tranchée d’Avesnelles qui par ailleurs s’avère être très pauvre en faune. The Uppermost Famennian “Etroeungt Limestone”, historically recognized by Gosselet, is the subject of a detailed presentation. Levels providing faunas are situated in the historic stratotype du Parcq quarry section at Etroeungt, and in the Avesnelles railway section, that has earlier been proposed as a parastratotype, because the sequence is incomplete in the du Parcq quarry. However, investigation for a new parastratotype is necessary because the upper limit is hidden in the Avesnelles railway section which also proves to be very poor in fauna.
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The Earliest Bats from Europe
- Chiroptera is one of the few modern mammal orders for which no fossil record has been associated with the Paleocene-Eocene Thermal Maximum that happened 55.8 million years ago. With the exception of complete skeletons from the early Middle Eocene of the Messel Formation in Germany and the late Early Eocene Green River Formation in Wyoming, all early bats are only represented by isolated elements, mainly teeth and fragmentary jaws, making the diversity and taxonomic affinities more difficult to establish. Here we revise all of the Early Eocene bats from Europe based on dental features, including digitally reconstructed teeth using micro-CT scanning technology of some complete skeletons. The diversity of European early bats is composed of the families Onychonycteridae, Icaronycteridae, Archaeonycteridae, Palaeochiropterygidae, and some of undetermined affinities. Dental features and synapomorphies of each family are characterized for the first time. The earliest bats are dated from the early Early Eocene and are all of small size with lower molars less than 1.3 mm in length. They are represented by: Eppsinycteris anglica from Abbey Wood, east London, England, an onychonycterid with reduced lower p4 and long molars; Archaeonycteris? praecursor from Silveirinha, Portugal, an archaeonycterid with long postcristid on wide lower molars; a new archaeonycterid genus and species from Meudon, North France with long trigonid and shorter postcristid on wide lower molars. These results indicate that the diversity of European Early Eocene bats is higher than previously recognized and that diversification began early in the Early Eocene.
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New primate postcrania from the Eraly Eocene of Vastan Mine, Gujarat, India
- The Cambay Formation at Vastan Mine in Gujarat yields the oldest fossil primates known from India. New age estimates suggest that the fossils date from approximately 54.5 Ma (early Ypresian), about 2 million years older than initially thought and comparable in age to early Wasatchian Wa-4 faunas from North America. The Vastan primate fauna comprises predominantly the asiadapine adapoids Marcgodinotius and Asiadapis. Two species of omomyid primates, Vastanomys gracilis and V. major, are much rarer, each known from a single dental specimen. In addition to primate dental remains, Vastan Mine has produced the best preserved early Eocene primate postcranial elements known from anywhere in the world. Here we present new limb bones, including humeri, ulnae, femora, tibiae, and a talus, from three of the recognized primate species. They include the first omomyid postcrania from India: two femora, a talus, and a potential proximal tibia. We also report additional asiadapine postcrania: a pristine femur of Marcgodinotius and the first complete tibia of Asiadapis. Five new humeri (two complete) consist of one asiadapine and four that lack specializations of either group, making allocation difficult. Two ulnae are attributed to indeterminate euprimates due to lack of adequate comparative material. The elements attributed to Vastanomys are more primitive than any other known omomyid postcrania and are only subtly different from those of asiadapines, in contrast to the more distinct postcranial bones of their middle and late Eocene relatives. The femora attributed to Vastanomys exhibit features suggestive of leaping behavior (cylindrical femoral heads, lateral condyle higher than medial, proximal position of the third trochanter), as in other omomyids. However, while the talus of Vastanomys resembles those of omomyids more than those of other primates, features such as the relatively short, medially angled neck, and oval rather than spherical head suggest that Vastanomys was not as specialized for leaping as younger omomyids. Although asiadapines have been described as close to notharctids in morphology, the relatively wider distal femur and symmetrical condyles of Marcgodinotius resemble adapids more than notharctids and may also reflect less leaping. The revised age of the fossils, together with the similarity in morphology of omomyid and asiadapine postcrania, suggests that the postcrania, like the teeth of the most primitive members of each family, are converging toward a common morphology as we approach the base of the Eocene.
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Prionus antonkozlovi n. sp. de Chine (Coleoptera, Cerambycidae, Prioninae)
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Biology and fisheries of the spotted flounder (Citharus linguatula) caught by multiple gears with partial spatiotemporal overlaps
- 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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A risk-based approach to cumulative effect assessments for marine management
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Monitoring en Modellering van het cohesieve sedimenttransport en evaluatie van de effecten op het mariene ecosysteem ten gevolge van bagger- en stortoperatie (MOMO). Activiteitsrapport 1 januari 2017 – 30 juni 2017
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Redescription of Cichlidogyrus tiberianus Paperna, 1960 and C. dossoui Douëllou, 1993 (Monogenea: Ancyrocephalidae), with special reference to the male copulatory organ
- The flatworms of the genus Cichlidogyrus Paperna, 1960 (Monogenea: Ancyrocephalidae) are gill parasites of freshwater fish, affecting predominantly the family Cichlidae. Cichlidogyrus tiberianus Paperna, 1960 and Cichlidogyrus dossoui Doue¨llou, 1993 are among the most widely distributed species of the genus, occurring in several African river basins and infecting many different host species, including the economically important Nile tilapia Oreochromis niloticus (Linnaeus) and redbreast tilapia Coptodon rendalli (Boulenger). Despite their wide distribution, C. tiberianus and C. dossoui have so far been studied only by light microscopy. In this paper they are redescribed on the basis of scanning electron microscopy of newly-collected material. The new material was obtained from redbreast tilapia caught in the Luapula River (D. R. Congo). The haptoral sclerites and genitalia are redescribed and illustrated in detail. Special attention is given to the complex morphology of the male copulatory organ.
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Capacity building for the Monitoring, Reporting and Verficiation (MRV) of biodiversity and ecosystem services in Africa
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Dusty baseline: the merit of museum collections in biological invasion studies
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Spatial and seasonal variation of biomineral suspended particulate matter properties in high-turbid nearshore and low-turbid offshore zones
- Suspended particulate matter (SPM) is abundant and essential in marine and coastal waters, and comprises a wide variety of biomineral particles, which are practically grouped into organic biomass and inorganic sediments. Such biomass and sediments interact with each other and build large biomineral aggregates via flocculation, therefore controlling the fate and transport of SPM in marine and coastal waters. Despite its importance, flocculation mediated by biomass-sediment interactions is not fully understood. Thus, the aim of this research was to explain biologically mediated flocculation and SPM dynamics in different locations and seasons in marine and coastal waters. Field measurement campaigns followed by physical and biochemical analyses had been carried out from 2004 to 2011 in the Belgian coastal area to investigate bio-mediated flocculation and SPM dynamics. Although SPM had the same mineralogical composition, it encountered different fates in the turbidity maximum zone (TMZ) and in the offshore zone (OSZ), regarding bio-mediated flocculation. SPM in the TMZ built sediment-enriched, dense, and settleable biomineral aggregates, whereas SPM in the OSZ composed biomass-enriched, less dense, and less settleable marine snow. Biological proliferation, such as an algal bloom, was also found to facilitate SPM in building biomass-enriched marine snow, even in the TMZ. In short, bio-mediated flocculation and SPM dynamics varied spatially and seasonally, owing to biomass-sediment interactions and bio-mediated flocculation.
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Benthic and fish aggregation inside an offshore wind farm: Which effects on the trophic web functioning?
- As part of the energy transition, the French government is planning the construction of three offshore wind farms in Normandy (Bay of Seine and eastern part of the English Channel, north-western France) in the next years. These offshore wind farms will be integrated into an ecosystem already facing multiple anthropogenic disturbances such as maritime transport, fisheries, oyster and mussel farming, and sediment dredging. Currently no integrated, ecosystem-based study on the effects of the construction and exploitation of offshore wind farms exists, where biological approaches generally focused on the conservation of some valuable species or groups of species. Complementary trophic web modelling tools were applied to the Bay of Seine ecosystem (to the 50 km2 area covered by the wind farm) to analyse the potential impacts of benthos and fish aggregation caused by the introduction of additional hard substrates from the piles and the turbine scour protections. An Ecopath ecosystem model composed of 37 compartments, from phytoplankton to seabirds, was built to describe the situation “before” the construction of the wind farm. Then, an Ecosim projection over 30 years was performed after increasing the biomass of targeted benthic and fish compartments. Ecological Network Analysis (ENA) indices were calculated for the two periods, “before” and “after”, to compare network functioning and the overall structural properties of the food web. Our main results showed (1) that the total ecosystem activity, the overall system omnivory (proportion of generalist feeders), and the recycling increased after the construction of the wind farm; (2) that higher trophic levels such as piscivorous fish species, marine mammals, and seabirds responded positively to the aggregation of biomass on piles and turbine scour protections; and (3) a change in keystone groups after the construction towards more structuring and dominant compartments. Nonetheless, these changes could be considered as limited impacts of the wind farm installation on this coastal trophic web structure and functioning.
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Treeline and timberline dynamics on the northern and southern slopes of the Retezat Mountains (Romania) during the late glacial and the Holocene
- Abstract To investigate treeline and timberline dynamics in the Retezat Mountains (Romanian Carpathians), late glacial and Holocene sediment sequences from four lakes were studied. The south and north slopes of the mountain range were compared using two lakes from the north flank (Lake Brazi, 1740 m a.s.l. and Lake Gales, 1990 m a.s.l) and two from the south flank (Lake Lia, 1910 m a.s.l. and Lake Bucura, 2040 m a.s.l.). Macrofossil and stomata analyses were performed to assess changes in the local vegetation, supplemented by pollen, charcoal and loss-on-ignition analyses. Our results show that treeline reached Lake Brazi on the northern side during the late glacial (ca. 14,000 cal yr BP) and then Lake Gales between 11,000 and 10,800 cal yr BP. During the early Holocene the upper limit of closed forest, the timberline, reached and passed Lake Brazi and has stayed above it since, but it has never reached Lake Gales at 1990 m a.s.l. The expansion of Larix decidua in the late glacialand early Holocene around Lake Brazi is unique. Stomata and macrofossils of Abies alba are also more abundant in the northern records. On the southern flank, treeline reached Lake Lia at around 12,000 cal yr BP, and was either very close to or at the elevation of Lake Bucura between ca. 8600 and 3000 cal yr BP. Timberline reached Lake Lia at ca. 8000 cal yr BP, some 3000 years after Lake Brazi, only 170 m lower on the north slope. Local fire events delayed the advance of timberline around Lake Lia in the early Holocene in a dry continental climate. The surrounding forest was dominated by Picea abies with individuals of Pinus cembra and stands of P. mugo until about 3000 cal yr \BP\ when timberline retreated below the lake. Maximum elevation of timberline was attained between ca. 8000 and 3000 cal yr BP, after which it descended in response to climate cooling. Regional climate change appears to be the main driver of treeline dynamics, but it was modified by local climatic differences due to slope aspect. The first signs of human disturbance appeared ca. 4200 cal yr BP, when naturally open areas were used as alpine pastures. Human impact in the treeline ecotone, mainly burning and grazing, was intensified after ca. 2600 cal yr BP, contributing to the widening of the ecotone and the lowering of the timberline.
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Design of flying robots inspired by the evolution of avian flight
- Bionic design of flying robots based on natural models has become a hot topic in mechanical engineering. The research going on in this direction considers that there is a lot to learn from flying animals such as birds, insects, and bats, from walking on the ground to getting enough power to be airborne. To get an efficient design of flying robots, we must better understand the origin of flight. This paper focuses on the review of avian flight and its possible application in the design of flying robots. Different hypotheses have been proposed to tackle the origin and evolution of avian flight from cursorial dinosaurs to modern birds, including the famous ground-up and tree-down theories. During the past decade, discoveries of feathered and winged dinosaurs from Liaoning, China, strongly supported the theory that birds originated from theropod dinosaurs. The transition from running on the ground to maneuver in the sky involves various stages of flights and plumages, which can be now illustrated by several representative paravian dinosaurs from Liaoning. Those fossils provide good research bases for the design of flying robots. Microraptor is one of those important transitional stages in the evolution of flight. This paravian dinosaur is characterized by the presence of pennaceous feathers along both its arms and its legs, but how it could actually fly is still debated. It is of course difficult to evaluate the flight performances of an extinct animal, but aerodynamics of a four-wing robot can be developed to get some knowledge about its flying capacity. Fossil and living flying animals with different morphologies, stability, and control mechanism can be a source of inspiration for designing socially relevant products.
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Shaking the wings and preening feathers with the beak help a bird to recover its ruffled feather vane
- The feather of a bird consists of barbs which again comprise numerous barbules with micro-hooklets. This hierarchically organized feather structure provides a smooth vane to bear the load from the airflow; however, the feather vane is vulnerable to disruption by external pulling forces during collision with the branches of a tree and hitting some small obstacles in flight or strong turbulence. The feather is unable to carry the weight of the bird's body if the vane could not be recovered immediately. Here we discovered that the feather vane can be re-established easily by birds themselves. A bird can always recover its feather vane from ruffled state by shaking its wings and preening its feathers with its beak because of the cascaded geometries of barbs and barbules. This biophysical mechanism of self-healing suggests that the hierarchical vane structure can be used to design artificial feathers for a flapping robot.
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The oldest freshwater crabs: claws on dinosaur bones
- With approximately 1,500 extant species, freshwater crabs (Decapoda: Brachyura) are among the most diverse decapod crustaceans. nevertheless, their fossil record is extremely limited: only potamidae, potamonautidae and trichodactylidae are reported up to the eocene of the neotropics so far. this work documents unusually large decapod claws from the Upper Cretaceous (Campanian) continental deposits of Velaux and vicinity (southern France), in close association with large vertebrate remains. In addition to (1) the systematic assignment of these claws, the study addresses (2) the salinity trends in the deposit environment from its faunal assemblage and the elementary chemical patterns of fossils, and (3) the likely scenario for their auto/allochthony in the Velaux fuvial system. These claws belong to a new taxon, Dinocarcinus velauciensis n. gen. n. sp., referred to as Portunoidea sensu lato, a group of “true” crabs nowadays linked to marine systems. However, the faunal assemblage, the claw taphonomy and the carbonates Y/Ho signatures support their ancient freshwater/terrestrial ecology, making them the oldest reported continental brachyurans and extending the presence of crabs in freshwater environments by 40 Ma. Either as primary or as secondary freshwater crabs, the occurrence of these portunoids in Velaux is an evidence for the independent colonizations of continental environments by multiple brachyuran clades over time, as early as the campanian.
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Palaeopathology of Iguanodon specimens from Museums in Belgium and Britain, and a comparison with pathological rates in Hadrosauridae
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L’herpétofaune du site Ramsar des Monts Birougou (Gabon) : catalogue illustré des espèces.
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Le Rubané en Belgique : nouvelle chronologie céramique et synchronisation avec les régions voisines
- Blouet V., Bosquet D., Constantin C., Fock H., Ilett M., Jadin I., Klag Th., Petitdidier M.-P., Thomashausen L., 2021. « Le Rubané en Belgique : nouvelle chronologie céramique et synchronisation avec les régions voisines ». Bulletin de la Société préhistorique française, tome 118 (07-2021), n° 2 : 277-322 + 9 Annexes en ligne. / Résumé. Des analyses statistiques réalisées à partir de 165 ensembles céramiques de Belgique et du Limbourg néer¬landais, totalisant 5 101 éléments de décors, permettent de proposer une périodisation en six phases et treize stades à valeur chronologique pour le Rubané de la Meuse. Cette séquence peut être synchronisée avec celles établies pour la région de Langweiler, la Lorraine française et le bassin de la Seine, ce qui permet de mieux caractériser chaque style régional et de mesurer les interactions entre les différents groupes de la zone d’étude. Les premières implantations du Limbourg et de Hesbaye relèvent du style de Flomborn qui s’impose, au Rubané ancien, dans tout le bassin du Rhin. À partir de l’étape moyenne, sur le cours moyen de la Meuse et en Hainaut, le Rubané partage avec le plateau d’Aldenhoven des motifs constitués de bandes délimitées remplies d’impressions au poinçon qui définissent un style Rhin-Meuse. Au Rubané récent, la Belgique se distingue par des bandes très larges remplies d’impressions au poinçon ou, plus fréquemment, au peigne à dents multiples. Ce style particulier, pour lequel il est légitime de conserver le terme d’Omalien, se distingue encore au Rubané final par une proportion majoritaire de motifs curvilignes, alors que partout ailleurs, ce sont les thèmes rectilignes qui s’imposent. À ces époques, la Hesbaye et le Hainaut se montrent relativement peu sensibles aux influences du style de Cologne, qui prédomine en Rhénanie du Nord. Depuis le Rubané moyen et jusqu’au Rubané final, la Lorraine du Nord entretient des échanges soutenus avec les régions mosanes, ce qui se traduit par des transferts de style, principalement en rive gauche de la Moselle, et par l’im¬portation massive de lames en silex du Maastrichtien et du Campanien de Belgique. Au Rubané terminal, une rupture semble se produire au moment de la mise en place du groupe de Blicquy-Villeneuve-Saint-Germain, qui forme une même entité stylistique entre le bassin de la Seine et la Belgique, régions qui jusqu’alors n’entretenaient pratiquement aucun échange. – Mots-clés : Belgique, Bassin de la Meuse, Néolithique ancien, Rubané, décor céramique, sériation, chronologie, styles régionaux. = Abstract: This article presents a new relative chronology for the Linearbandkeramik (LBK) of the Meuse basin. Divided into six main phases, the sequence is based on analysis of decorated ceramics from sixteen sites in Belgium and two sites in Holland. Eleven of the Belgian sites are located in Hesbaye, the province with the densest LBK set¬tlement. The other five sites form an outlying group in Hainaut, a little over 100 km to the west. The two Dutch sites are located in southern Limburg, about 50 km north-east of Hesbaye. Fine-ware ceramics were coded for rim, main and intermediate decoration motifs, employing a classification system previously developed in work on the LBK in Lorraine, with particular attention paid to the various techniques used for impressed decoration. The new Meuse basin sequence was established using 165 assemblages containing at least eight decoration motifs, representing a total of 5 101 coded motifs. In a majority of cases, these assemblages were formed by grouping ceramics from lateral pits of houses. Correspondence analysis and hierarchical clustering were used to seriate the assemblages and to define phases and sub-phases. By comparing quantitative trends in decoration motifs, the new Meuse chronology can be synchronized with the Lang¬weiler (Aldenhoven plateau), Lorraine and Seine basin LBK sequences, not only enabling a finer characterization of each regional style but also enhancing the view of interactions between the different groups in the study zone. During the early LBK, the period that sees the first settlements in Hesbaye and north Lorraine, the Flomborn style pre¬vails throughout the Rhine basin. When this cultural entity breaks down, decoration evolves in each region in a different manner. In the middle LBK, the Langweiler area, Dutch Limburg and Belgium form a coherent complex, termed the Rhine-Meuse style, characterized by bands delimited by incised lines and filled with rows of point impressions, which is the majority decoration. In the Moselle basin, as in southern Hessia, the Main style prevails, predominately with bands filled with transverse, crossed or longitudinal incised lines, while in the Seine basin the Champagne region is closely linked in stylistic terms to southern Alsace. The late LBK sees further regional differences, notably with the appearance of the Leihgestern style on the upper course of the Lahn, in central Hessia, and the emergence of the Cologne style in the lower Rhine. The Belgian LBK remains relatively unaffected by these processes and maintains its originality by developing the excessively broad curvilinear motifs, composed of bands filled with incised lines or with multiple-tooth (three or more teeth) comb impressions. These motifs characterize the Omalian style. In north Lorraine, the Main style remains important but the region is now split into two, with on the right bank of the Moselle a strong presence of the Oberrhein-Pfalz style, whose epicentre lies in the Palatinate, and on the left bank a predominance of Omalian influences. These favoured stylistic relations are also reflected by the circulation of lithic raw materials: on the middle and lower course of the Moselle, most of the flint tool-kit is made from blades in Maastrichtian and Campanian flint, imported from the Meuse basin as semi-finished products. In return, one finds in Hainaut, on the site of Blicquy “Petite Rosière”, Moselle-type motifs in noticeably higher numbers than attested elsewhere in Belgium. In the same period, on the upper course of the Moselle, the LBK of south Lorraine is linked to northern Alsace, while the Champagne LBK maintains its preferential relations with south¬ern Alsace. Throughout the late LBK, there is only limited interaction and exchange between these two groups and the Meuse, lower Rhine and middle Moselle. In the final LBK, the situation is more difficult to assess because the documentation varies in quality from one region to another. At this time, the Langweiler area is apparently abandoned by the LBK, while the Omalian-style LBK still flourishes in Hesbaye and to a lesser extent in Hainaut. On the middle course of the Rhine, new cultural entities appear, with the emergence of the Hinkelstein group on the Neckar and in the northern Palatinate, and the development of the Plaidt style on the lower course of the Moselle, from the Rhine confluence up to Luxembourg. A particular style appears in north Lorraine, derived from the Oberrhein-Pfalz style, while in south Lorraine another original style develops, combining elements from southern and northern Alsace as well as from north Lorraine. In the Seine basin, the LBK spreads northwards and westwards out of Champagne, settling the middle and lower courses of the Aisne and Yonne. Here again, one sees the formation of an original style, characterized by T motifs and predominant use of two- or three-toothed combs, at a time when combs with four or more teeth are more frequently used on the Meuse. At this stage, there is virtually no exchange between the Meuse and the Seine, while the middle Moselle distances itself stylistically from the Omalian but still imports large numbers of blades in Campanian flint from Hesbaye. The preferential relations maintained between Belgium and north Lorraine during the LBK apparently cease in the ter¬minal LBK stage. At this time, the Blicquy-Villeneuve-Saint-Germain (BVSG) culture appears in the Seine basin and in Belgium, possibly slightly earlier in Hainaut than in Hesbaye. The emergence and subsequent development of this new stylistic entity represents a significant change, because there is relatively little evidence for contacts between Belgium and the Seine basin during the previous LBK phases. In the terminal LBK, the Moselle basin finds a new supply of raw material in the Secondary and Tertiary flint of Champagne. The early BVSG site of Reims-Tinqueux shows that this “economic” exchange is also accompanied by some stylistic interaction. – Keywords: Belgium, Meuse basin, Early Neolithic, Linearbandkeramik, ceramic decoration, seriation, chronology, regional styles. https://www.researchgate.net/publication/359112408_Le_Rubane_en_Belgique_nouvelle_chronologie_ceramique_et_synchronisation_avec_les_regions_voisines
