Search publications of the members of the Royal Belgian institute of natural Sciences
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Large-scale and small-scale population genetic structure of the medically important gastropod species Bulinus truncatus (Gastropoda, Heterobranchia)
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Reevaluating the timing of Neanderthal disappearance in Northwest Europe
- Understanding when Neanderthals disappeared is a hotly debated topic. When radiocarbon dating placed the Spy Neanderthals amongst the latest surviving in Northwest Europe, questions were raised regarding the reliability of the dates. Using a procedure more efficient in removing contamination and ancient genomic analysis, we show that previous dates produced on Neanderthal specimens from Spy are too young by up to 10,000 y. Our direct radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-Forêt show a reduction of the uncertainty for the time window corresponding to Neanderthal disappearance in Northwest Europe. This population disappeared at 44,200 to 40,600 cal B.P. (at 95.4% probability). This is also earlier than previous suggestions based on dates on bulk collagen.Elucidating when Neanderthal populations disappeared from Eurasia is a key question in paleoanthropology, and Belgium is one of the key regions for studying the Middle to Upper Paleolithic transition. Previous radiocarbon dating placed the Spy Neanderthals among the latest surviving Neanderthals in Northwest Europe with reported dates as young as 23,880 ± 240 B.P. (OxA-8912). Questions were raised, however, regarding the reliability of these dates. Soil contamination and carbon-based conservation products are known to cause problems during the radiocarbon dating of bulk collagen samples. Employing a compound-specific approach that is today the most efficient in removing contamination and ancient genomic analysis, we demonstrate here that previous dates produced on Neanderthal specimens from Spy were inaccurately young by up to 10,000 y due to the presence of unremoved contamination. Our compound-specific radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-Forêt demonstrate that they disappeared from Northwest Europe at 44,200 to 40,600 cal B.P. (at 95.4% probability), much earlier than previously suggested. Our data contribute significantly to refining models for Neanderthal disappearance in Europe and, more broadly, show that chronometric models regarding the appearance or disappearance of animal or hominin groups should be based only on radiocarbon dates obtained using robust pretreatment methods.All the radiocarbon data generated at the ORAU are archived internally and are also available on the laboratory’s website, along with a link to the paper. The mitochondrial genome from Fonds-de-Forêt is deposited in GenBank with the accession number PRJEB39136. All other study data are included in the article and/or SI Appendix.
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Chapter 12 - New Specimens of Frugivastodon (Mammalia: Apatotheria) from the Early Eocene of India Confirm Its Apatemyid Status and Elucidate Dispersal of Apatemyidae
- We here describe 18 new specimens of the sole apatemyid mammal known outside North America and Europe: Frugivastodon cristatus from the early Eocene Cambay Shale Formation of Vastan Lignite Mine, Gujarat, India. This mammal was previously represented by a single isolated lower molar, which hindered the establishment of its relationships among Apatemyidae. The new fossils show that the Indian apatemyid is unique and represents a new morphotype among this family. It is notably characterized by mesiodistally elongated lower molars with a reduced m3, a small hypocone on the upper molars, and a transversely wider M1 than in other apatemyids. The new data supports the inclusion of the enigmatic Uintan Aethomylos within Apatemyidae. The Indian Frugivastodon and the North American Aethomylos might represent a distinct clade of Apatemyidae that originated around the Paleocene-Eocene boundary. A paleobiogeographic analysis suggests that Frugivastodon dispersed from Europe into India during the early Ypresian. We also review the dispersal events that characterized the history of Apatemyidae.
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Recent advances in heteromorph ammonoid palaeobiology
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Potential impact of wash water effluents from scrubbers on water acidification in the southern North Sea
- Sulphur Oxides (SOx) in atmospheric ship emissions resulting from the burning of fuel with high sulphur content are known to be harmful to human and ecosystem health. Since January 1st 2020, the International Maritime Organisation (IMO) lowered the previous limit for sulphur content in ship fuel from 3.5% m/m (mass by mass) to 0.50%. In the emission control areas (SECAs), the limit for the sulphur content had been set to 1.0% in 2010 and is kept below 0.1% since 2015. To comply with these limits, ship operators and owners can switch to fuel oil with lower sulphur content (LSFO). Alternatively, they can continue to burn fuel with high sulphur content by using technical means such as exhaust gas cleaning systems (or scrubbers) that reduce the atmospheric SOx emissions to a level equivalent to the required fuel oil sulphur limit. Scrubbers use sea water as cleaning media to remove SOx from the air emissions. There are three main categories of scrubbers: (1) the open-loop scrubbers that continuously discharge their wash water effluent, (2) the closed-loop scrubbers that treat the wash water before it is discharged, and (3) the hybrid scrubbers that can switch from open to closed modes. Scrubbers transform the air pollution into direct marine discharge. As hybrid scrubbers are more likely to discharge their sulphur waste into sea water rather than using land infrastructures, they are hereafter taken as open-loop ones. The effect of SOx contribution from ship on sea water pH is assessed for the English Channel and the southern North Sea by means of a marine biogeochemical model that includes a detailed description of the carbonate chemistry. This model allows testing different scenarios of SOx contribution resulting from the maritime traffic. To this end, realistic scenarios with ship traffic density estimated for the years 2019, 2020 and 2030, assuming a year-to-year ship traffic increase of 3.5% and several SOx pollution reduction strategies have been tested. An additional model simulation with null SOx contribution from the shipping sector is used as a reference level to comparatively assess the impact of each scenario on the sea water pH. Model results show a pH decrease of 0.004 units over the whole domain in case of a 2019-like ship traffic density with 15% of the fleet (in Gross Tonnage) using open-loop and hybrid scrubber systems. For future scenarios, assuming that 35% of the fleet is equipped with open-loop and hybrid scrubbers, the pH is estimated to decrease by 0.008 to 0.010 units in average over the whole domain. The magnitude of pH changes is not evenly distributed through space. According to the model results, the largest pH changes would occur in areas of high traffic density, such as along the Belgian and Dutch coasts and in the vicinity of large harbours such as Rotterdam. Ocean acidification rate attributed to climate change is estimated at 0.0017-0.0027 pH units per year. In comparison, the total pH decrease owing to the use of open-loop scrubbers would be equivalent to 2 to 4 years of climate change acidification on average over the whole domain, and to 10 to 50 years, in more local areas. The cumulative impact of ocean acidification due to climate change and to maritime traffic should therefore be considered in ecosystem assessment studies.
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Deposits from the 2004 Indian Ocean Tsunami in three coastal ponds in Khao Lak, Thailand
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Etude pétrographique de terres cuites architecturales (TCA) du Forum romain de Bavay.
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Cranial asymmetry in odontocetes: a facilitator of sonic exploration?
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A cooperative game-theoretic framework for negotiating marine spatial allocation agreements among heterogeneous players.
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Consistent patterns of spatial variability between NE Atlantic and Mediterranean rocky shores
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Geographic patterns of biodiversity in European coastal marine benthos
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Essence of the patterns of cover and richness of intertidal hard bottom communities: a pan-European study.
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The role of physical variables in biodiversity patterns of intertidal macroalgae along European coasts.
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Age of mud breccia from mud volcanoes in Academician Ridge, Lake Baikal
- Lake Baikal is the only freshwater reservoir on Earth with gas-hydrate accumulations in its bottom sediments, partly due to the activity of mud volcanoes. This paper describes a group of mud volcanoes recently discovered on the slope of the Academician Ridge between the northern and central Lake Baikal basins. Our analysis of diatom skeletons in the mud breccia sampled from the study area shows a high abundance of Cyclotella iris et var. These extinct species were also discovered in a core sample from BDP-98 borehole. Based on the biostratigraphic and seis-mostratigraphic correlations, the age of the mud breccia in the studied mud volcanoes ranges from the Late Miocene to the Early Pliocene (4.6 to 5.6 Ma). The correlations suggest that the material originated from a depth of less than 310 m below the lake bottom.
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High-amplitude lake-level changes in tectonically active Lake Issyk-Kul (Kyrgyzstan) revealed by high-resolution seismic reflection data
- A total of 84 seismic profiles, mainly from the western and eastern deltas of Lake Issyk-Kul, were used to identify lake-level changes. Seven stratigraphic sequences were reconstructed, each containing a series of delta lobes that were formed during former lake-level stillstands or during slow lake-level increase or decrease. The lake level has experienced at least four cycles of stepwise rise and fall of 400202fm or more. These fluctuations were mainly caused by past changes in the atmospheric circulation pattern. During periods of low lake levels, the Siberian High was likely to be strong, bringing dry air masses from the Mongolian steppe blocking the midlatitude Westerlies. During periods of high lake levels, the Siberian High must have been weaker or displaced, and the midlatitude Westerlies could bring moister air masses from the Mediterranean and North Atlantic regions.
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Towards answering the “so what” question in marine renewables environmental impact assessment
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Lessons learned from the Belgian offshore wind farm monitoring programme, with specific attention to answering the “so what” question
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A fossil heron from the early Oligocene of Belgium : the earliest temporary well-constrained record of the Ardeidae
- We describe the earliest temporally well-constrained fossil that can be assigned to the Ardeidae (herons), from the lowermost Oligocene (32.0–33.0 million years ago) of Belgium. The specimen, a partial tarsometatarsus, belongs to a small species and is described as Proardea? deschutteri n. sp. It exhibits the characteristic tarsometatarsus morphology found in extant heron species, but a confident assignment to one of the ardeid subclades is not possible and even the assignment of the new fossil species to the crown group (the clade including the extant species) cannot be established. The fossil indicates a divergence of herons from their sister taxon by at least the earliest Oligocene, and current paleontological data suggest that herons arrived in Europe shortly after a major faunal turnover at the Eocene/Oligocene boundary. We consider that dispersal is the likely reason for the sudden appearance of herons in the earliest Oligocene of Europe but it is uncertain from where exactly this took place, with Asia and Africa being among the candidate areas.
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Letters to the twenty-first century botanist. Second series:“what is a seed?”–3. How did we get there? Palaeobotany sheds light on the emergence of seed
- This paper discusses the main steps leading to the acquisition, during the Palaeozoic, of the seed habit. The earliest spermatophytes originated in the Late Devonian and produced small cupulate ovules characterized by an elaborated sporangial apex involved in pollination. The diversification of ovules during the Carboniferous led to a wider range of sizes and shapes, and an increasing importance of the integument. The earliest seeds containing embryos are reported in Carboniferous coniferophytes.
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A peculiar fish jaw with molariform teeth from the early Eocene of Tadkeshwar Mine, India highlights diversity and evolution of early gymnodont tetraodontiforms
- Excavations during 2015 at a channel deposit in the early Eocene Cambay Shale Formation of the Tadkeshwar open cast lignite mine near Vastan in Gujarat Province, western India, have yielded terrestrial mammals, lizards, snakes, frogs, and birds as well as a few marine/brackish-water animals, predominantly teeth of the shark Physogaleus and Myliobatis rays. Among these is a jaw of an unusual teleost. This lower jaw of a gymnodont has fused dentaries, lacks a beak, and shows a remarkable series of teeth that are unique among all known fossil and living Tetraodontiformes. The teeth are molariform with raised “spokes” radiating inward from the emarginated peripheral edge of the crown. Tooth development is intraosseous, with new teeth developing in spongy bone before they erupt and attach to the dentary by pedicels. Although many of the 110 tooth loci in the fossil specimen have lost their teeth, in life the teeth would have grown to fit tightly together to form a broad and continuous crushing surface. The estimated age of the early Eocene Cambay Shale vertebrate fauna is ca. 54.5 Ma, making the jaw the second oldest confirmed gymnodont fossil. Comparisons to extant taxa of gymnodonts with fused dentaries (e.g., Diodon, Chilomycterus, and Mola) offer few clues about evolutionary relationships of the new fossil. Although the fused dentaries suggest affinities to diodontids and molids among living tetraodontiforms, it remains challenging to interpret phylogenetic relationships of the new Indian gymnodont because no living or fossil tetraodontoid has similar tooth morphology. We describe it as a new genus and species, and place it in its own new family of Gymnodontes. Grant Information: National Geographic Society, Leakey Foundation, Belgian Science Policy Office, Tontogany Creek Fund, National Science Foundation, Wadia Institute of Himalayan Geology.
