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The development of geothermal energy is below the European National Renewable Energy Action Plans' anticipated trajectory. For deep geothermal energy projects in particular, multiple sources of uncertainty in combination with high upfront investment costs result in a major investment risk, hampering the mobilization of required capital (Compernolle et al., 2019). The uncertainty sources include market uncertainty, uncertainty regarding new technologies and uncertainty inherent to working with subsurface data. The objectives of the DESIGNATE project for deep geothermal systems in Belgium, including applications in abandoned mines are two folds. First, to create tools for integrated forecasts under uncertainty and second to set-up a methodological framework for territorial Life Cycle Analysis (LCA) considering surface and subsurface impacts. To do so, analytical reservoir models will be developed to assess the effect of uncertainties about geological data and concepts on the performance and impact of the geothermal applications. These will be coupled with a techno-economic analysis in combination with a territorial, environmental life cycle analysis. To evaluate the impact of different policy measures, the techno-economic analysis consists of a Monte Carlo simulation model that integrates both market and geological uncertainties and a project developers' option to wait or abandon the geothermal project development at different steps in the development of the project (Welkenhuysen et al., this conference). As a preliminary step, the influence of the rollout time of a heat network on the risk and on the profitability is investigated. At the start often only a part of the district heating network is in place at the time of commissioning and the geothermal plant operates at much lower capacity. Part of the capacity is foreseen for district heating networks linked to residential districts expected to be built or renovated in the near future. In this research, the change in income of a project considering a stepwise rollout of a district heating network compared to a full load from the start, in combination with a reduced maximum capacity of the geothermal plant compared to the expected output is calculated. This is done with a simplified spreadsheet techno-economic model, limiting variability to the rollout scenarios. For the calculation, data provided by the project developer HITA of the Turnhout NW geothermal project is used. In the next section the four cases used to evaluate the risk and profitability linked to the changes in the rollout time of a heat network are described. In the first case, the base case, the production plant is assumed to work at full capacity once the construction of the geothermal plant is achieved. Full capacity means that the production plant will be working at 100% during the heating season. Additional production for cooling or for heat storage in summertime are not taken into account. The second case considers that the maximum production capacity is 20% lower than in the first case due to lower-than-expected reservoir temperature or flow rate. In the third case, the full capacity is equal to the one of the base case but will be reached in three steps, simulating a growing demand by adding new district heating networks. The demand is expressed as a percentage of the expected maximum production capacity of the geothermal plant. At the start of production, the geothermal plant runs at 50%. After 5 years this is increased to 75% and after 10 years full capacity is reached. The fourth and last case is similar to the third case, with a stepwise increase of the demand, but the maximum production capacity is, as in second case, 20% lower. Because the demand is lower than the total capacity in the first 10 years, the production plant will however be able to supply the required energy. Only after 10 years when the demand rises to the expected maximum production capacity, only 80% of the required energy can be delivered without additional investments. As such, the income of the project will be the same the first 10 years compared to the third case. In a best-case scenario, demand and rollout of a district heating network will be fast and the production plant will run at full capacity during the heating season from the start (case 1). This is however unlikely and assuming this to be the base case will result in many projects not reaching predetermined targets, as the income of the project will be lower during the first years of production. In this respect, the third case or a similar scenario is a better option to use as a base case. This will put more stringent conditions on the expected output parameters of the production well to ensure an economic viable project, and hence provide a more realistic outlook. When using case 3 as the base case this also has the complementary benefit of reducing the risk related to the maximum production capacity. If the real maximum production capacity is lower than expected, the reduction of income will be lower than the decrease in the maximum production capacity. In other words, a reduction of 20% of the maximum production capacity will not lead to a reduction of 20% of the income, but will be between 0 and 20%, depending on the interest rate and on the time frame to reach full capacity. Acknowledgments This research is carried out under the DESIGNATE project, which receives funding from the BELSPO BRAIN-be 2.0 research programme under contract nr B2/191/P1/DESIGNATE. HITA kindly provided input for the development for this case study. References Compernolle, T., Welkenhuysen, K., Petitclerc, E., Maes, D. & Piessens, K., 2019. The impact of policy measures on geothermal energy investments. Energy Economics, 84, 104524. https://doi.org/10.1016/j.eneco.2019.104524 Welkenhuysen, K., Compernolle, T., Kaufmann, O., Laenen, B., Meyvis, B., Piessens, K., Gousis, S., Dupont, N., Harcouet-Menou, V. & Pogacnik, J., this conference. Decision support under uncertainty for geothermal applications: case selection and concept development.

Knowledge on the environmental impacts of geothermal energy is of major importance to understand the role this technology could play in the transition towards sustainable energy systems. Life cycle analysis (LCA) methodology is a widely used tool for assessing the environmental impacts of products and systems, which has been implemented numerous times on geothermal systems. Previous reviews on geothermal LCA studies identify large variability on the reported environmental impacts. In this work we aim to provide a more in-depth analysis to explain the variability across the different LCAs. We review 28 LCA studies on geothermal energy published between 2005 and 2020, following a four step reviewing sequence; in step 1 we identify the LCA methodological choices and the plant geo-technical characteristics, in step 2 we identify the LCA results and the LCI inputs, in step 3 we perform contribution analysis based on the reported results and in step 4 we investigate the sensitivity and scenario analysis performed in the studies. If the data is available we triangularly evaluate the reported impacts considering a) the plants’ geo-technical characteristics, b) the hotspot analyses results and c) the Life cycle inventory (LCI) inputs. We focus our analysis on the six most frequently assessed impact indicators (GWP, AP, HTP, FETP, CED, ADP)* and distinguish between the different energy conversion technologies used for geothermal energy exploitation. This way we aim to provide a more transparent picture on the variability of environmental impacts across the LCAs by focusing on the environmental hotspots and on the cause-effect relationships between geo-technical parameters and the environmental impacts. We also aim for drawing LCA guidelines for future LCA studies on geothermal systems and proposing methods for impact mitigation. The variability on the LCA results is caused by differences on the choices of the LCA practitioners, on the energy conversion technologies used, on geological parameters and on plant design parameters. Most studies focus on the GWP and AP impacts, while information for the rest of the impacts is much more limited. For flash and dry steam power plants the direct emissions of non-condensable gases (NCGs) emerging can cause high GWP, AP, FETP and HTP impacts depending on the geofluid’s composition. The CED and ADP impacts are dominated by the steel and diesel consumption during the development of the wells. Thus differences on the geo-technical parameters determining the power output and the total material and energy consumption cause the variability on the reported results. Direct emissions of NCGs do not emerge in plants utilizing binary technology. In these plants the development of the wells dominates the impacts and this phenomenon is more intense when EGS-binary plants are investigated due to the large depth drilled. Also the production of the working fluid used in the ORC and its annual leakage can highly affect the GWP impact in these plants depending on the type of working fluid used. In heating plants high amounts of grid-electricity are needed for the plant operation as no power is produced. Therefore differences in the fossil-fuel-intensity of the electricity mix supplying the plant can result in large variability. The choice of the LCA practitioner to include or not the heat distribution network in the boundaries of the system also affects the results, while a significant portion of the impacts is caused during the development of the wells. Combined heat and power plants using flash or binary technology present similar results. However the co-production of heat and power is expected to lead to some benefits. A direct correlation between the GHGs and the NH3/H2S direct emissions with the GWP and AC impacts, respectively, is observed for flash and dry steam power plants. Direct emissions are determined by the geofluid composition which highly varies between different reservoirs. For mitigating these impacts the installation of abatement systems shall be considered, while the identification of the geofluid composition and of the natural emissions emerging prior to the plant development is suggested for estimating the actual anthropogenic emissions. For plants utilizing binary technology and heating plants it is observed that higher capacity generally leads to lower GWP and AP impacts per functional unit. The capacity is a product function of the temperature and production flow. Similar observation can be extracted for the temperature while this is not the case for the flow. No clear correlation can be seen between the impacts and the depth. This is because larger depths lead –on the one hand– to higher impacts because of higher material and energy consumption which are compensated –on the other hand– to the increase on the fluid temperature and flow. For mitigating impacts caused during the construction phase the use of renewable energy sources for supplying the machinery used is suggested, while proper fluid re-injection should be designed for keeping the capacity constant during the operation. Also for binary plants the working fluid shall be selected such that its GWP impact is low, while for heating plants the installation of a small ORC unit shall be considered if the conditions are appropriate for meeting the pumping needs of the plant. The reviewed studies show that geothermal energy exploitation can lead to significant environmental benefits compared to fossil sources, as most of the times the impacts caused by geothermal plants are in the range of other renewable sources. Further research is needed on deep geothermal energy exploitation to better understand its environmental impacts. A significant portion of the impacts is caused during the operation of the plants regardless of the technology used (direct emissions, electricity consumption, working fluid losses, make-up well drilling). All of the LCA studies reviewed are static LCAs. Thus a dynamic LCA framework considering the time aspect is needed for better estimations of the environmental impacts. Also consequential LCAs on geothermal energy plants need to be conducted in order to assess how the global environmental impacts may change by the wider implementation of geothermal energy. In addition, future LCA studies shall also focus on environmental impacts other than the GWP as information regarding them is limited. Finally the sustainability of geothermal investments is to be further explored by investigating the social impacts of geothermal development and comparing them to other energy sources but also the financial aspect of such investments. Acknowledgments This research is carried out under the DESIGNATE project, which receives funding from the BELSPO BRAIN-be 2.0 research program under contract nr B2/191/P1/DESIGNATE. * GWP: Global Warming Potential, AP: Acidification Potential, HTP: Human Toxicity Potential, FETP: Freshwater EcoToxicity Potential, CED: Cumulative Energy Demand, ADP: Abiotic resources Depletion Potential

One of the greatest challenges of the last decades in the fight against climate change has been to achieve net-zero emissions by mid-century. According to the US EPA (2016), in 2014, global anthropogenic emissions of carbon dioxide (CO2) accounted for ~64% of the greenhouse effect. Carbon dioxide capture and storage (CCS) plays an irreplaceable part as a mitigation technology that avoids CO2 emissions at their source and bridges the transition into a non-carbon-based energy future. The International Energy Agency (IEA) estimates that the need to store CO2 will grow from 40 Mt/y at present to more than 5000 Mt/y by 2050. Additionally, in the IEA’s Sustainable Development Scenario, which aims for global net-zero CO2 emissions from the energy sector by 2070, CCS needs to become a global industry supporting emissions reductions across the overall energy system. CCS technologies essentially consist of capturing and compressing the CO2 at the source and then transport it towards deep suitable rock formations where it is injected to be permanently stored. The key to successful and permanent CO2 storage is the proper analysis and characterization of the reservoir and seal formation. Among the types of reservoir suitable for CO2 storage are unmined coal beds, depleted oil and gas fields, EOR/EGR, saline aquifers, man-made caverns, and basaltic formations (IPCC, 2005). The storage capacity of any of these reservoirs is the subsurface commodity whose quantities and properties are assessed when existing data is provided. Capacity estimations bring their own level of uncertainty and complexity according to the scale at which they are addressed and the nature of the geological conditions of the reservoir. This degree of uncertainty should be accounted for in every estimation (Bradshaw et al., 2007) Resource classification systems (RCS) are frameworks that establish the principles and boundaries for each level of capacity assessment. By making use of these frameworks, it is possible to properly allocate the stage of development of a resource (United Nations, 2020). For every level of assessment, the principles of the estimation change and so do the scale and purpose. As the analysis moves forward, a prospective site develops and exhaustive information is acquired, initial estimations are adjusted, and uncertainty is likely to reduce. Additionally, different economic, technical, regulatory, environmental and societal factors are integrated into the assessment to bring the estimations under present conditions. For instance, if the storage capacity is to be matched with a CO2 source, detailed simulations and analyses regarding injectivity, supply rate, potential routes and economic distances must be performed to achieve a realistic estimation. However, an assessment where the main goal is to merely quantify the space available to store CO2 in a reservoir, does not consider the aforementioned limitations and will carry higher risk and uncertainty in its estimation (Bradshaw et al., 2007). Even though resource classification systems provide a solid foundation for CCS projects, they do not provide the input parameters and analyses needed to reach every level of assessment. This is why storage capacity estimation methodologies go hand in hand with RCS given that the former can give information related to the parameters and constraints considered in the estimation. No standard process has been proposed that can be followed from the starting level of a CO2 storage capacity assessment until a fully developed carbon storage resource; that is, a CO2 storage site ready to become fully operational. This paper aims to develop a methodology where the fundamental steps needed to go through every level of the resource classification systems are standardized. This methodology intends to serve as a general baseline that, regardless of the geological settings and techno-socio-economic conditions, can be adopted for any CCS assessment. The proposed methodology is built by reviewing the available capacity estimation methods for every level of assessment and identifying social, technical and economic aspects that come into play as the resource is being developed. Considering that capacity estimation methodologies can vary their approach even for the same level of assessment, the rationales behind them are expected to be determined. Such rationales can be related to in-place policy restrictions, geographical economic behavior, or the nature of the parameters contemplated. Additionally, PSS, an in-house developed tool that can assess CO2 storage reservoirs at different levels, will be proposed within the methodology. This tool is a bottom-up geotechnical and economic forecasting simulator that can generate source-sink matching for CCS projects, where technical, economic, and geological uncertainties are handled through a Monte Carlo approach for limited foresight (Welkenhuysen et al., 2016). Acknowledgements This research is carried out under the LEILAC2 project, which receives funding from the European Union’s Horizon 2020 research and innovation program under grant agreement number 884170. The LEILAC2 consortium consists of: Calix Europe SARL, HeidelbergCement AG, Ingenieurbüro Kühlerbau Neustad GmbH (IKN), Centre for Research and Technology Hellas (CERTH), Bundesanstalt für Geowissenschaften und Rohstoffe (BGR), Politecnico di Milano (POLIMI), Geological Survey of Belgium (RBINS-GSB), ENGIE Laborelec, Port of Rotterdam, Calix Limited, CIMPOR-Indústria de Cimentos SA and Lhoist Recherche et Development SA. References Bradshaw, J., Bachu, S., Bonijoly, D., Burruss, R., Holloway, S., Christensen, N. P., & Mathiassen, O. M. (2007). CO2 storage capacity estimation: Issues and development of standards. International Journal of Greenhouse Gas Control, 1(1), 62–68. https://doi.org/10.1016/S1750-5836(07)00027-8 IPCC. (2005). Carbon Dioxide Capture and Storage. https://www.ipcc.ch/report/carbon-dioxide-capture-and-storage/ United Nations. (2020). United Nations Framework Classification for Resources: Update 2019. UN. https://doi.org/10.18356/44105e2b-en US EPA. (2016). Global Greenhouse Gas Emissions Data. US EPA. https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data Welkenhuysen, K., Brüstle, A.-K., Bottig, M., Ramírez, A., Swennen, R., & Piessens, K. (2016). A techno-economic approach for capacity assessment and ranking of potential options for geological storage of CO2 in Austria. Geologica Belgica. http://dx.doi.org/10.20341/gb.2016.012

X-ray computed tomography (CT-) scanning is revolutionizing the study of extinct organisms. Its non-invasive and non-destructive character makes it currently by far the most potent method to allow fossils to be studied in three dimensions and with unprecedented detail. More importantly, and differing from other 3D techniques, CT-scanning looks through and inside objects, revealing hidden structures and characters. Recent innovations in the field of CT-scanning allow obtaining details up to a few micrometers in resolution, and higher quality images of relatively dense materials, like fossils, even when wholly encased in hard sediment (Keklikoglou et al., 2019). In 2016, the Royal Belgian Institute of Natural Sciences (RBINS) acquired two high-end X-ray CT machines: the micro-CT RX EasyTom and the nano-CT XRE-Tescan UniTom. Both scanners are currently nearly full time in use to help accomplishing the gigantic task of the digitization of the RBINS and Royal Museum for Central Africa (RMCA) type collections, the aim of two multi-year Belspo funded projects, DiSSCo-Fed (2018-2023) and DIGIT-4 (2019-2024). With about 300.000 types and 48.000.000 general specimens, 46.000 and 3.000.000 respectively in their paleontology collections, the results of nearly two centuries of intensive collecting and research, these two Belgian Federal Scientific Institutions (FSI’s) are major players in the European framework of scientific research infrastructures for natural history. Digitizing this large number of types, spread across almost the entire Tree of Life, and exhibiting an entire array of differing taphonomies, results in a steadily growing expertise of the RBINS-RMCA micro-CT lab (Brecko et al., 2018). While the newly acquired infrastructure and ongoing digitization projects are primarily oriented towards the digitization of type and figured specimens, these also offer great opportunities for researchers and teachers in various disciplines of paleontology. Targeting on researchers interested in incorporating micro-CT as a technique in their research projects, the current digitization workflow of the RBINS-RMCA micro-CT lab will be presented. While micro-CT offers many advantages, there are also pitfalls and limitations that need to be considered. Based on our expertise, and illustrated by some of our scanning results, important constraints that may block the pathway between your expectations and perfect micro-CT-imaging results that can be fully incorporated into research projects will be presented. Possible effects of some of the most important parameters that may influence the quality of the output, and thus can increase the signal to noise ratio (SNR) will be reviewed, such as the size and shape of the specimen to be scanned, the density of its matrix the specimen is made of or encased in, the presence of certain minerals (e.g. pyrite) and how these may be distributed inside the specimen (e.g. finely disseminated, dense masses or crystals), the best possible resolution in relation to the specimen and preferred output, the time needed to scan a specimen, the choice between machines to be used and their limits and different possible scan settings (e.g. beam power, filters…). Post-processing parameters to be considered are the size of the image stack output (will the computer be able to handle the amount of Gigabytes?), the time needed to render and segment regions of interest and optimize 3D-models, and which format suits best to visualize and export the data (renderings, meshes, videos, virtual sections…). While segmentation may be a time-consuming task, new developments like the incorporation of artificial intelligence (e.g. the Deep Learning function in Dragonfly ORS) offer great potential to reduce the workload in complex segmentation. Many researchers are also teachers. The reason why they may also be particularly interested in the 3D models of the already digitized types that are available on the Virtual Collections platforms of the RBINS (http://virtualcollections.naturalsciences.be/) and RMCA (https://virtualcol.africamuseum.be/). While 3D models are not intended to replace physical specimens, they may become significant teaching aids in both the physical and virtual classroom. In addition, the presence of a steadily growing number of 3D-models and animations of extant animals that are also added to these Virtual Collections, would allow teachers to connect fossils (in general incomplete) with extant (more complete) relatives. Last but not least, while the focus of this communication is largely on micro-CT, some of the many other new techniques that are being tested, used and improved will be highlighted (see e.g. Brecko & Mathys, 2020; Brecko et al., 2014, 2016, 2018; Mathys et al., 2013, 2019 for some examples). Interested in our work, expertise, techniques, equipment, or scans-on-demand? Please do not hesitate to reach out! References Brecko, J., Lefevre, U., Locatelli, C., Van de Gehuchte, E., Van Noten, K., Mathys, A., De Ceukelaire, M., Dekoninck, W., Folie, A., Pauwels, O., Samyn, Y., Meirte, D., Vandenspiegel, D. & Semal, P. 2018. Rediscovering the museum’s treasures: μCT digitisation of the type collection. Poster presented at 6th annual Tomography for Scientific Advancement (ToScA) symposium, Warwick, England, 10-12 Sept 2018. Brecko, J. & Mathys, A., 2020. Handbook of best practice and standards for 2D+ and 3D imaging of natural history collections. European Journal of Taxonomy, 623, 1-115. Brecko, J., Mathys, A., Dekoninck, W., De Ceukelaire, M., VandenSpiegel, D. & Semal, P., 2016. Revealing Invisible Beauty, Ultra Detailed: The Influence of Low-Cost UV Exposure on Natural History Specimens in 2D+ Digitization. PLoS One 11(8):e0161572. Brecko, J., Mathys, A., Dekoninck, W., Leponce, M., Vanden Spiegel, D. & Semal, P., 2014. Focus stacking: Comparing commercial top-end set-ups with a semi-automatic low budget approach. A possible solution for mass digitization of type specimens. Zookeys, 464, 1-23. Keklikoglou, K., Faulwetter, S., Chatzinikolaou, E., Wils, P., Brecko, J., Kvaček, J., Metscher, B. & Arvanitidis, C. 2019. Micro-computed tomography for natural history specimens: a handbook of best practice protocols. European Journal of Taxonomy, 522, 1-55. Mathys, A., Semal, P., Brecko, J. & Van den Spiegel, D., 2019. Improving 3D photogrammetry models through spectral imaging: Tooth enamel as a case study. PLoS One, 14(8): e0220949. Mathys, A., Brecko, J., Di Modica, K., Abrams, G., Bonjean, D. & Semal, P., 2013. Agora 3D. Low cost 3D imaging: a first look for field archaeology. Notae Praehistoricae, 33/2013, 33-42.

Multituberculates are an extinct rodent-like order that lived between Late Jurassic and late Eocene, on almost every continent. Due to their extraordinary longevity, their evolutive history is important to understand. One of the most numerous and best-preserved groups is the superfamily Djadochtatherioidea from the Late Cretaceous of the Gobi Desert. All djadochtatherioid genera are monospecific, except Kryptobaatar. The large number of K. dashzevegi fossils come from Outer Mongolia, while the only two specimens found in Bayan Mandahu, Inner Mongolia, China belong to K. mandahuensis. However, a new particularly well-preserved specimen (IMM 99BM-IV/5) found in Bayan Mandahu during the 1990s Sino-Belgian expeditions seems at first sight very close to K. dashzevegi. IMM 99BM-IV/5 consists of a skull associated with cervical and thoracic vertebrae, ribs, shoulder girdle, broken right humerus and an almost complete left forelimb. It is the first specimen for which the hand is described in detail. Based on micro-CT scan and comparison, it appears that IMM 99BM-IV/5 presents morphological characters of both species of Kryptobaatar, as well as new characters of its own. Phylogenetic analysis suggests that IMM 99BM-IV/5 has an intermediate position between K. dashzevegi and K. mandahuensis and could therefore belong to a new species. However, Kryptobaatar is paraphyletic in the resulting tree, which raises again questions about intraspecific variability in multituberculates. Since only 13 specimens of Kryptobaatar out of the hundreds found have been studied, it is impossible to reliably know if IMM 99BM-IV/5 is included in the variability of K. dashzevegi or not. However, it is crucial to know this variability to define whether the genus is monospecific or not. By comparing K. mandahuensis with published specimens, we concluded that it is a valid species. This work also highlighted the lack of knowledge of the variability of the type species K. dashzevegi, without which it is impossible to clearly assign IMM 99BM-IV/5. Finally, endemism alone is not the cause of this variability, but the role of paleoenvironment or age is currently unknown.

The Crocodylia include all modern crocodiles, alligators, caimans and gharials, and their extinct relatives. They are an ancient lineage that originated around 70 million years ago. Recently, the field of crocodylian paleontology has experienced a rise in attention from researchers, however, much is still unknown about the early evolution of this group. Our research describes newly discovered fossil material comprised of a small crocodylian skull and associated partial lower jaw of early Paleocene age. It was discovered during a Belgian-Chinese expedition in Qianshan Basin, Anhui Province, China, as part of a bilateral cooperation project between the Royal Belgian Institute of Natural Sciences and the Institute of Botany of the Chinese Academy of Sciences. In the present study, the fossil material is formally described for the first time. Micro-CT scans are made to visualize internal anatomical structures, as well as characters hidden by the sediment. A comprehensive morphological study is executed, revealing that the specimen is a juvenile. It likely constitutes a new species and genus, as it differs from other crocodyloids by several autapomorphies. A phylogenetic analysis based on morphological characteristics reveal that this specimen is the most basal taxon among Crocodyloidea, a group that comprises all species more closely related to modern crocodiles than to modern alligators, caimans, or gharials. Although it is not the oldest crocodyloid ever reported, it is the earliest crocodyloid in Asia. Moreover, its basal phylogenetic position implies that it is part of an ancient ghost lineage of crocodyloids that had already been around in Asia for a longer time. The presence of crocodyloid remains in the Late Cretaceous of North America and the late Paleocene of Europe suggests that crocodyloids may have migrated there from Asia early on in their evolutionary history.

La compréhension progressive des différents réchauffements climatiques intenses du Paléogène inférieur (PETM, ETM-2, EECO…) a créé un intérêt évident pour une stratigraphie de plus en plus fine des bassins sédimentaires qui ont enregistrés ces événements. Ces derniers, identifiés sur base géochimique, demandent à être corrélés avec les événements biologiques qui en découlent et qui ont été, eux aussi, enregistrés dans ces bassins. Dans ce cadre, les bassins parisien, de Londres et de Belgique, formant le sud du Bassin de la Mer du Nord, représentent des modèles de choix pour la communauté géoscientifique de par leur reconnaissance historique et les étages internationaux Lutétien, Yprésien et Thanétien qu’ils ont respectivement permis de définir. Si les connaissances sur les dépôts marins ont fait d’énormes progrès notamment grâce aux études micropaléontologiques détaillées, qu’en est-il aujourd’hui des dépôts continentaux souvent délaissés par leur complexité à être interprétés? Vingt-cinq ans d’expertise en biochronologie mammalienne de notre équipe bruxelloise et de ses collaborateurs sont ici survolés, mettant en exergue l’utilité des mammifères en stratigraphie et paléogéographie. L’exposé porte tant sur des taxons marqueurs que des faunes entières issues de sites historiques ou nouveaux du Bassin parisien et de son complémentaire le bassin belge (Hainin, Maret, Rivecourt, Dormaal, Erquelinnes, Meudon, Sotteville-sur-Mer, Egem, Oosterzele…). Ainsi, des niveaux de référence de l’échelle biochronologique européenne des mammifères du Paléogène (MP) sont précisés, de nouveaux âges à mammifères européens sont identifiés et la stratigraphie tant à l’échelle locale que nord-ouest européenne est affinée. Malgré tout le travail accompli, les questions sont nombreuses et beaucoup reste à faire tant l’étude des faunes de mammifères est incomplète!

The paleobotanist Philippe Gerrienne was internationally renowned for his work on early land plants. His research career was however not limited to the study of Devonian floras. He also actively contributed to the progress of Belgian Wealdian (Early Cretaceous), early Paleogene and Quaternary research. In this framework, Philippe’s interest for Paleogene plants already appeared when he helped to sort Stockmans’ paleobotanical collections of the Royal Belgian institute of Natural Sciences (RBINS) during a civil service he did between 1987 and 1989. In the old conservatoires, he discovered hundreds of silicified trunks and branches from the “upper Landenian” (early Eocene) of Belgium, which were collected in 1970 in the area of Hoegaarden during the construction of the Brussels-Liège highway (E40-A3). From 1994, the RBINS developed new research activities in early Paleogene Belgian sites. At this occasion, fossil plants discovered next to vertebrates from the warm earliest Eocene at Dormaal were studied in collaboration with the Royal Museum for Central Africa, which owns an excellent xylotheque of tropical woods (Doutrelepont et al., 1997). This first step allowed in 1999, after several preliminary works, to start a partnership with the University of Liège (ULiège) and the University of Mons (UMons) through a F.R.F.C.-I.C. (FNRS) project, leaded by Muriel Fairon-Demaret (ULg), on the "Reconstruction of the terrestrial ecosystems in Belgium during the Palaeocene-Eocene transition, 50-60 million years ago". During three years (1999-2002), numerous fieldworks in Belgium and research activities in labs were realized, including a first database of more than 600 hundreds fossil wood specimens. In this overview, I summarize the main accomplishments that have been done in the field. At Péruwelz, we found a silicified trunk fragment of a new arborescent Ericaceae in the marine Thanetian (Upper Paleocene), which was named Agaristoxylon garennicum (Gerrienne et al., 1999). The paleoenvironment of Dormaal was reconstructed based on fruits and seeds from the Paleocene Eocene Thermal Maximum (Fairon-Demaret & Smith, 2002). The most successful work was probably the study of the in situ monospecific Glyptostroboxylon forest of Overlaar at Hoegaarden (Fairon-Demaret et al., 2003). This warm Everglades-like paleoenvironment attracted the Belgian media and finally led to the construction of the geopark of Hoegaarden. In 2004, Philippe described the Givetian (middle Devonian) seed precursor Runcaria heinzelinii Stockmans, 1968 from Ronquières, Belgium (Gerrienne et al., 2004). The rediscovery of the 385-million-year-old basal seed plant and, the same year, the retirement of his close colleague Muriel Fairon-Demaret focused definitively his interest on the Paleozoic. References Doutrelepont, H., Smith, T., Damblon, F., Smith, R. & Beeckman, H., 1997. Un bois silicifié de peuplier de la transition Paléocène-Eocène de Dormaal, Belgique. Bulletin de l'Institut royal des Sciences naturelles de Belgique, 67, 183-188. Fairon-Demaret, M. & Smith, T., 2002. Fruits and seeds from the Tienen Formation at Dormaal, Paleocene-Eocene transition in eastern Belgium. Review of Palaeobotany and Palynology, 122, 47-62. Fairon-Demaret, M., Steurbaut, E., Damblon, F., Dupuis, C., Smith, T. & Gerrienne, P., 2003. The in situ Glyptostroboxylon forest of Hoegaarden (Belgium) at the Initial Eocene Thermal Maximum (55 Ma). Review of Palaeobotany and Palynology, 126, 103-129. Gerrienne, P., Beeckman, H., Damblon, F., Doutrelepont, H., Fairon-Demaret, M. & Smith, T., 1999. Agaristoxylon garennicum Gerrienne et al., gen. et sp. nov., an arborescent Ericaceae from the Belgian Upper Paleocene: palaeoenvironmental implications. Review of Palaeobotany and Palynology, 104, 299-307. Gerrienne, P., Meyer-Berthaud, B., Fairon-Demaret, M., Streel, M. & Steemans, P., 2004. Runcaria, a Middle Devonian Seed Plant Precursor. Science, 306, 856-858.

Avec plus d’un an de retard suite à la crise COVID (Anthropocène supérieur), nous présentons ici un squelette partiel d’un hibou fossile de grande taille qui entretemps a déjà été publié (Mayr et al., 2020). Ce retard n’est toutefois pas réellement préjudiciable étant donné que le spécimen a été découvert il y a déjà plus de 30 ans dans les couches du Wasatchien moyen (Wa-3) de la Formation de Willwood à McCullough Peaks, au Wyoming (USA), permettant ainsi de le dater entre 54,5 et 55,0 Ma (début de l’Eocène inférieur). Le spécimen inclut la majorité des os postcraniens d’un des strigiformes fossiles les plus complets du Paléogène. Primoptynx poliotaurus mesurait environ 50 centimètres de long, taille comparable à Hedwig, le harfang des neiges de Harry Potter, et appartient à un groupe de hiboux proche de la famille éteinte des Protostrigidae, bien que ne partageant pas avec ces derniers la morphologie dérivée du tibiotarse. Les pattes de Primoptynx sont différentes de celles des strigidés actuels (hiboux et chouettes). Les hiboux ont aujourd'hui quatre doigts avec des griffes de même taille pour attraper des proies relativement petites, et les tuer avec le bec. Primoptynx a les premier et second doigts plus longs, comme on le voit chez les éperviers, buses, aigles et autres membres de la famille des Accipitridae. Ces deux doigts plus développés sont utilisés pour épingler les proies, qui sont dès lors percées par les serres. Primoptynx était donc un hibou qui chassait comme un aigle, des mammifères de taille moyenne. Ce fossile montre, avec d’autres découvertes, que durant l’Eocène inférieur il y avait déjà une certaine diversité de strigiformes, de différentes tailles, qui occupaient diverses niches écologiques. Le succès des hiboux allait de pair avec celui des mammifères, devenus très diversifiés à l’Eocène inférieur. L'extinction ultérieure de Primoptynx et d'autres proto-hiboux pourrait être due à l'émergence d'oiseaux de proie diurnes à l'Éocène supérieur. Financements Cette étude a été menée dans le cadre du projet BR/121/A3/PalEurAfrica, financé par la Politique Scientifique Fédérale Belge. Références Mayr G., Gingerich P.D. & Smith T., 2020. Skeleton of a new owl from the early Eocene of North America (Aves, Strigiformes) with an accipitrid-like foot morphology. Journal of Vertebrate Paleontology, 40(2):e1769116. https://doi.org/10.1080/02724634.2020.1769116.

The Cretaceous is a key period for anurans, as several clades, such as the aquatic Pipidae and the speciose Neobatrachia (~96 % of extant taxa) underwent a rapid and vast diversification. This event is considered to have taken place on Gondwana, as it was breaking apart into several continents, including South America and Africa. Fossiliferous sites from this period from both continents are key to understand how this diversification unravelled. Unfortunately, few cretaceous sites with anuran remains are known from Africa. Among them is the Ibeceten site from the Coniacian-Santonian of Niger. Located in the South-East of Niger, this site has been the subject of several field campaigns during the 1970s by the Muséum national d’Histoire naturelle, Paris. The peculiar pipid Pachycentrata taqueti was described in 1998. However, most of the material remained undescribed. Here we present a thorough study of the anuran material from Ibeceten, which leads to the recognition of a new taxon. New anatomical studies suggest the presence of at least six taxa, although numerous bone fragments remain unattributable. This makes Ibeceten the most diverse anuran fauna of the African fossil record. Half of the identified taxa belong to Pipimorpha (total-group of Pipidae), while another one is an ornamented anuran that resembles the cretaceous neobatrachians from South America. Among the pipids, one new taxon should be erected. Phylogenetic analysis of pipimorphs places two Ibeceten taxa among the pipids. The presence of more than one pipid shows that the clade was already diversified during the early Late Cretaceous, and that the clade might have emerged in Africa, before spreading to South America. In addition, the putative presence of a neobatrachian shows that the clade was already widespread in South America and West Africa.