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Un cheval du Bruxelles médiéval, souffrant d'un trouble de la colonne vertébrale
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RBINS Staff Publications 2023
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A raven (Corvus corax) from medieval Brussels with pathologies: was it truly free as a bird?
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RBINS Staff Publications 2023
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Solving the missing pieces of the gharial puzzle: new phylogenetic framework combining morphological, molecular, and biostratigraphic data to unravel the evolution of long-snouted crocodylians.
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Among the extant crocodylians are two species with long, narrow snouts: Gavialis gangeticus,the Indian gharial and Tomistoma schlegelii, the "false" gharial. These enigmatic species are considered by the IUCN red list as critically endangered and vulnerable, respectively. However, despite this, knowledge of their evolutionary history is lacking. Extensive debate has surrounded the gharials for over four decades and remains unsolved today: the so-called gharial problem. Whereas molecular studies consistently indicate that these two species are sister taxa, morphological studies of both living and fossil taxa find that they belong to distantly related lineages. Moreover, molecular clock estimates indicate a shallow divergence time of 18-31 million years ago. This entirely contradicts the rich fossil record of gharials: in contrast to the modern gharials, these fossil taxa comprise a huge diversity and suggest that tomistomines and gavialines have diverged from each other at least 70 million years ago, prior to the K/Pg mass extinction. European museums, and especially the Royal Belgian Institute of Natural Sciences, Brussels, comprise rich collections containing many of the oldest fossil gavialoids, crucial to solving the gharial problem. Nevertheless, few modern morphological studies have been performed on these specimens, and their stratigraphic age is often poorly constrained. Therefore, in a new project we will use a multidisciplinary approach to study these specimens, combining morphological study and biostratigraphic analyses using dinoflagellate cysts. Moreover, we will revise the classical methods used by paleontologists to study fossil crocodylians, devising a new phylogenetic framework that makes use of both morphological, molecular, and biostratigraphic data. Here, we will present some of the first preliminary results of this project.
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RBINS Staff Publications 2023
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Geochemistry of nummulites as proxy for Eocene climate change in the Southern North Sea Basin
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RBINS Staff Publications 2019
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Geochemistry of nummulites as proxy for Eocene climate change in the Southern North Sea Basin.
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RBINS Staff Publications 2019
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Geochemistry of Nummulites as a proxy for the Eocene paleotemperature evolution in the Southern North Sea Basin: an Ypresian test case.
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RBINS Staff Publications 2019
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Foraminiferal response to early Eocene climate variability in the North Sea Basin.
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Dating the latest appearance of Neanderthals in Belgium
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Belgium represents a key region for studying the Middle to Upper Palaeolithic transition (MUPT) in North-West Europe. This area sits at the crossroads between Palaeolithic cultural facies with influences from eastern, western and southern Europe intermingling during the Late Middle Palaeolithic and the MUPT. Until recently, a temporal gap believed to be around 4ka (ca 42-38 ky calBP) existed between the Late Mousterian and the earliest dated Aurignacian settlements in the region [1, 2]. The dates obtained on Neanderthal remains from Spy fell into this gap, making them the latest Neanderthals in the region [3]. Including the dates from Spy, a gap of two millennia remained between the dates on Neanderthals and the beginning of the Aurignacian. Based on this chronological evidence, the transition from Neanderthals to Anatomically Modern Humans (AMH) in this region was believed to have been without contact between species. AMH would have settled in an area Neanderthals abandoned long before. As part of the PalaeoChron project, we have redated the Neanderthal specimens from Spy (tooth, maxilla and scapula), Engis 2 (skull and tooth) and Fond-de-Forêt (femur), using the compound specific radiocarbon dating method in place at the Oxford Radiocarbon Accelerator Unit. This method is based on the extraction of the amino acid hydroxyproline that occurs in mammalian collagen using preparative liquid chromatography. This method is more efficient than others in eliminating modern carbon contamination such as conservation materials. In this presentation, we report the new radiocarbon dates obtained on the Belgian Neanderthal specimens. These results show how much impact sample preparation can have on the AMS measurement when specimens have been heavily preserved with conservation materials, which is often the case for human remains. These results also now place the Belgian Neanderthal remains from Spy, Engis and Fond-de-Forêt in their proper chronometric context and allow us to refine our understanding of the disappearance of Neanderthals in north-western Europe and integrate this with other evidence for the human occupation of this region during the Palaeolithic.
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RBINS Staff Publications 2019
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The gait of Homo naledi
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Remains of the foot, upper and lower limb, thorax and cranium of Homo naledi present a mosaic of primitive and Homo-like traits. These include curved phalanges in the hands, although a human like wrist and palm, an ape-like thorax with Homo-like vertebrae, and a shoulder girdle indicative of climbing competency. The individual bones of the foot and lower limbs largely seem to show an individual compatible with obligate bipedalism, although the pedal phalanges also show curvature [1,2]. Despite the remarkably voluminous assemblages, the H. naledi remains do not include a complete lower limb confidently ascribed to a single individual. A complete lower limb of H. naledi would be informative in what it could tell us regarding potential locomotion. The aim of this study was to reconstruct the lower limbs of the H. naledi skeleton and analyse the potential gait of H. naledi whilst also reviewing recent work on the functional morphology of H. naledi and how this pertains to inferences about bipedal locomotion. The H. naledi lower limb was constructed using estimated femoral, tibial and fibular lengths from the most complete remains of H. naledi currently available [2,3]. Pelvis remains were too fragmented to reconstruct the pelvis. All transformations were performed in ‘LhpFusionBox’, which is a musculoskeletal software primarily used to analyse gait in clinical contexts, but recently adapted for paleoanthropologists [4]. Estimated lengths were used as a reference to reconstruct the individual bones by using anatomical land-marks (ALs) to scale other H. naledi material to the size of the estimated bones. Both a modern human model and new lower limb associations of a juvenile skeleton found in the Dinaledi chamber were used as guides to reconstruct a complete lower limb. Reconstructions of individual isolated and scaled limb and foot bones were then placed together to have a complete lower limb re- construction taking into account ligaments, muscles and following the orientation of joint surfaces. The entire limb was then fused to a modern human walking motion to analyse potential locomotion. The reconstruction and biomechanical analysis of the H. naledi lower limb largely demonstrates a morphology compatible with obligate bipedalism, with a medial arch (although reduced), elongated limbs, marked bicondylar angle and joint surfaces compatible with bipedal gait. The elongation of the lower limb is generally seen as a marker of obligate bipedalism although the H. naledi limbs are exceptionally elongated relative to the diaphyseal diameter of the long bones and preserved joint proportions. Longer limbs are generally thought of as more energy efficient, but they also require a greater moment of inertia, which increases energy costs. Whilst the longer tibia (and leg) may have necessitated a longer swing phase, low limb mass (as evidenced by long bone gracility and small joints) may have offset this energetically. Other unique traits such as the flaring ilium, flattened femoral lower neck and overall general mix of primitive and Homo-like traits may not have impeded obligate bipedalism, but they may have been advantageous for climbing. Primitive traits are often thought of as vestiges of an ancient past on the way to the modern human form of obligate bipedalism, however, Homo erectus and other skeletons from the genus Homo are largely thought to be fully obligate bipedals from approximately 1.5 million years onwards, and as H. naledi has been dated between 335 and 236ka [5], it is therefore curious why this particular branch of the hominid tree would ‘hang on’ to the ‘primitive traits’ for at least a million years longer. It is therefore likely that this hominin engaged in both arboreal climbing and bipedal walking.
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RBINS Staff Publications 2019
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Doubling the number of high-coverage Neandertal genomes
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Over the last few years, the recovery and the analyses of genomes of ancient modern humans, Neandertals, and Denisovans have changed our understanding of the origins, the movements, and the relatedness of archaic and modern human populations. How- ever, in many cases endogenous DNA represents such a small fraction of the DNA extracted from specimens that sequencing of the complete ancient genomes is economically infeasible. Thus, to date, only three Neandertal genomes have been sequenced to high coverage [1-3]. Even though Neandertal genome sequences of low coverage [4] can be used to reconstruct various aspects of Neandertal genetic history, many analyses, for example estimation of population size and levels of inbreeding, rely on the reliable diploid genotypes. Recent studies have shown that certain skeletal elements, such as the inner part of the petrous bone and the ce- mentum layer in teeth [5 and references therein], may preserve DNA better over time. There is also evidence that the preservation of endogenous DNA may vary substantially even within a few millimeters distance in a single specimen [2, 4]. Due to the value and scarcity of ancient hominin remains, it is critical that the smallest possible amount of destructive sampling is involved in the recovery of genetic material. A usual sampling strategy typically involves taking around 50 mg of powder from a single location of a given bone or tooth. We investigated here whether taking multiple smaller samples in a step-wise manner of the Neandertal specimens from the Mezmaiskaya Cave in Russia and the Troisième caverne of Goyet in Belgium may improve the yield of an- cient human DNA. We removed between 8.5 and 27.2 mg of bone powder from a Mezmaiskaya 1 rib fragment, between 2.5 and 35.1 mg from a Mezmaiskaya 2 skull fragment, and between 5.8 and 53.8 mg from the Goyet Q56-1 femur fragment, amounting to between 15 and 38 powder subsets per specimen and an average input of 16.6 mg of powder per extraction. Importantly, to minimize the impact of contamination, we treated each powder aliquot with 0.5\% sodium hypochlorite solution prior to DNA extraction. The DNA extracts from the same specimen varied by several orders of magnitude in their proportion of endogenous DNA (between 0.07\% and 54.7\%), their content of nuclear genomes (between 0.01 and 78-fold coverage), as well as in the levels of present-day human contamination (0.2-50.3\%). There was no significant correlation between the amount of powder used for the extraction and the overall amount of the endogenous DNA or the levels of present-day human DNA contamination. Thus, these results indicate that ancient DNA preservation varies greatly within one specimen and that the removal of multiple, small sub-samples instead of one larger sample, here coupled with a decontamination procedure, can drastically improve the likelihood of isolating large enough amounts of DNA to make whole genome sequencing feasible. This approach allowed us to identify extracts with exceptionally high endogenous DNA content and low levels of present-day human DNA contamination (2\%), enabling us to generate three additional high-coverage Neandertal genomes. The high-quality genome sequences of multiple Neandertals form a unique reference resource for the scientific community and are valuable for analyses that require reliable diploid genotypes and haplotype information. For example, these data open new opportunities to investigate Neandertal population history, to identify genetic variants that arose uniquely on the Neandertal lineage and might have changed through time, and to determine those that may underlie archaic-specific traits or adaptations.
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RBINS Staff Publications 2019
