Search results

The end-Cretaceous mass extinction, 66 million years ago, profoundly reshaped the biodiversity of our planet. After likely originating in the Cretaceous, placental mammals (species giving live birth to well-developed young) survived the extinction and quickly diversified in the ensuing Paleocene. Compared to Mesozoic species, extant placentals have advanced neurosensory abilities, enabled by a proportionally large brain with an expanded neocortex. This brain construction was acquired by the Eocene, but its origins, and how its evolution relates to extinction survivorship and recovery, are unclear, because little is known about the neurosensory systems of Paleocene species. We used high-resolution computed tomography (CT) scanning to build digital brain models in 29 extinct placentals (including 23 from the Paleocene). We added these to data from the literature to construct a database of 98 taxa, from the Jurassic to the Eocene, which we assessed in a phylogenetic context. We find that the Phylogenetic Encephalization Quotient (PEQ), a measure of relative brain size, increased in the Cretaceous along branches leading to Placentalia, but then decreased in Paleocene clades (taeniodonts, phenacodontids, pantodonts, periptychids, and arctocyonids). Later, during the Eocene, the PEQ increased independently in all crown groups (e.g., euarchontoglirans and laurasiatherians). The Paleocene decline in PEQ was driven by body mass increasing much more rapidly after the extinction than brain volume. The neocortex remained small, relative to the rest of the brain, in Paleocene taxa and expanded independently in Eocene crown groups. The relative size of the olfactory bulbs, however, remained relatively stable over time, except for a major decrease in Euarchontoglires and some Eocene artiodactyls, while the petrosal lobules (associated with eye movement coordination) decreased in size in Laurasiatheria but increased in Euarchontoglires. Our results indicate that an enlarged, modern-style brain was not instrumental to the survival of placental mammal ancestors at the end-Cretaceous, nor to their radiation in the Paleocene. Instead, opening of new ecological niches post-extinction promoted the diversification of larger body sizes, while brain and neocortex sizes lagged behind. The independent increase in PEQ in Eocene crown groups is related to the expansion of the neocortex, possibly a response to ecological specialization as environments changed, long after the extinction. Funding Sources Marie Sklodowska-Curie Actions, European Research Council Starting Grant, National Science Foundation, Belgian Science Policy Office, DMNS No Walls Community Initiative.

organisé par la Société Royale belge d’Anthropologie et de Préhistoire et le Collège Belgique le 26 mai 2023 au Palais des Académies (Bruxelles). Résumé du colloque

The International Council for the Exploration of the Sea (ICES; French: Conseil International pour l'Exploration de la Mer, CIEM) is an intergovernmental marine science organization that brings together the efforts and knowledge of 20 Member States, bordering the North Atlantic and the Arctic Circumpolar Zone, on physical oceanography, marine ecosystems and fisheries management. Nowadays, more than 80 Belgian scientists are directly involved in the work of the 160 bodies and expert groups of ICES, which gather the expertise of more than 1500 scientists yearly, totalling up to 5000 scientists from over 700 marine institutes and organizations over the years. This important and often voluntary dedication of Belgian scientists to the work of ICES deserves more visibility among the Belgian scientific community itself and to policy makers.This is, among others, why the BICEpS initiative was launched in 2018. BICEpS general aim is to offer a platform to the Belgian ICES community to get to know each other, to improve collaboration and share information, and to promote ICES to the wider scientific community in Belgium. BICEpS Annual report 2019 presents the second year of activity of this initiative created to reinforce Belgian ICES people. The report targets marine scientists, marine managers and policy makers. It presents the results of the initiative so far. The report contains the list of Belgian ICES members in 2019 with their membership to the different ICES working groups, and the results of the second BICEpS Colloquium organised on 2 December 2019 and hosted by ILVO in Ghent (Summary of the sessions, abstracts of communications presented and list of participants). The abstracts of the colloquium are supplemented by a separate annex published online which assembles the PowerPoint presentations of the colloquium accessible at http://ices.dk/community/groups/Documents/BICEPS/BICEpS19-PPT-presentations.pdf The full report is accessible on the ICES website at http://ices.dk/community/groups/Pages/BICEpS.aspx

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.

The sustainable use and management of natural resources in border regions require unambiguous geological information from neighbouring countries. However, the available data often lack compatibility and the same level of detail across borders. Aim of the Belgian-Dutch H3O projects is to produce seamless, cross-border, 3D geological and hydrogeological models of the Cenozoic deposits across the border between Belgium and The Netherlands. “H3O – De Voorkempen” is the third consecutive project, focusing on the Noorderkempen (Flanders) and the western part of Noord-Brabant (The Netherlands). The project started in 2020 and the final results will be delivered in 2023. A crucial step in any cross-border geological modelling task is to establish the correlation between lithostratigraphic units on both sides of the border. In this project, the correlation is initially based on the available knowledge of regional lithostratigraphy (including chronology, depositional environment, sedimentological characteristics) and then further fine-tuned based on the interpretation of high-quality boreholes, geophysical well logs and seismic lines that cover the main geological complexities and cross the international border. The correlations are graphically presented in a chrono-lithostratigraphic correlation chart and cross-section profiles. The established correlation scheme will be used as a base for converting or reinterpreting the available data. In the final stage, the harmonized datasets will be used to create a geometrically and stratigraphically consistent 3D model of “De Voorkempen”. The result will be a state-of-the-art reference for the subsurface structure of the project area, which can be used as a base for scientific research and cross-border management of natural resources. The Belgian-Dutch H3O projects are carried out by a partnership between TNO – Geological Survey of the Netherlands, VITO and RBINS – Geological Survey of Belgium, with support from the Flemish Bureau for Environment and Spatial Development (VPO), Flanders Environment Agency (VMM), Province of Noord-Brabant and drinking water company Brabant Water. The geological models are/will be available in the public domain via the online data portals of DOV (Database of the Subsoil in Flanders) and DINOloket (Data and Information on the Dutch Subsurface). For the technical reports of previous H3O projects, see Deckers et al., 2014 and Vernes et al., 2018. References Deckers, J., Vernes, R.W., Dabekaussen, W., Den Dulk, M., Doornenbal, J.C., Dusar, M., Hummelman, H.J., Matthijs, J., Menkovic, A., Reindersma, R.N., Walstra, J., Westerhoff, W.E. & Witmans, N., 2014. Geologisch en hydrogeologisch 3D model van het Cenozoïcum van de Roerdalslenk in Zuidoost-Nederland en Vlaanderen (H3O-Roerdalslenk). VITO/TNO report, Mol/Utrecht, 208 pp. (incl. 8 appendices). Vernes, R.W., Dekkers, J., Bakker, M., Bogemans, F., De Ceukelaire, M., Doornenbal, J., den Dulk, M., Dusar M., Van Haren, T., Heyvaert, V., Kiden, P., Kruisselbrink, A., Lanckacker, T., Menkovic, A., Meyvis, B., Munsterman, D., Reindersma, R., Rombaut, B., ten Veen, J., van de Ven, T., Walstra, J. & Witmans N., 2018. Geologisch en hydrogeologisch 3D model van het Cenozoïcum van de Belgisch-Nederlandse grensstreek van Midden-Brabant / De Kempen (H3O – De Kempen). TNO/VITO/KBIN-BGD report, Utrecht/Mol/Brussel, 109 pp. (+8 appendices).

Raoellidae are extinct small-sized semiaquatic artiodactyls that are the closest relatives to crown clade Cetacea. They display morphological features showing the transition between terrestrial and aquatic lifestyles and therefore bring crucial information to understand the earliest steps of cetacean evolution. Raoellid cranial morphology, including the ear region and endocranial morphology, has been documented using cranial remains referred to Indohyus indirae from the Kalakot area, Jammu and Kashmir in India. The study of these specimens highlighted that several cetacean features are already present in raoellids. The previously available Indohyus material was very deformed, preventing access to quantitative data and leading to potential misinterpretations. We describe new undeformed cranial material from the Kalakot area, documenting another raoellid species, Khirtharia inflata. The new observations allow us to complete our knowledge of raoellid cranial morphology, including the original shape of the cranium and brain endocast and to confirm the specificities of raoellid morphology within Artiodactyla. We further provide the first quantitative data for the different brain components and show that Raoellidae had low encephalization and neocorticalization values, much lower than cetaceans and close to early diverging, primitive, dichobunoid artiodactyls. Reconstruction of the blood sinuses above the cerebellum supports the previous “intraosseous” hypothesis about the initial steps of the development of the caudal venous rete mirabile in cetaceans. The presence of several cetacean cranial features in Raoellidae, such as the peculiar shape of the frontal, the strong postorbital constriction, the periotic involucrum, or the elongation of the olfactory bulbs, questions the definition of the Cetacea clade.