-
Morphological, acoustic and genetic identification of a reproducing population of the invasive African clawed frog Xenopus laevis (Anura, Pipidae) recently discovered in Belgium
-
The African clawed frog (Xenopus laevis) is an aquatic invasive species of amphibian imported from South Africa for medical research and aquarium pet trade. Released on purpose or by accident, an invasive spread of Xenopus laevis to natural ecosystems was registered on most continents. In the absence of natural predators, their population densities can increase quickly causing damage to local aquatic ecosystems. Using external morphology of adults and tadpoles, osteology from high-resolution microcomputed tomography, vocalization analysis and DNA sequence data, this study assessed the identity of a reproducing Belgian Xenopus population at the current northernmost edge of the distribution of the genus in Europe. Morphological analysis of adult and tadpoles confirms that the Xenopus population from Comines-Warneton belongs to the species Xenopus laevis. Genetic analysis indicates two phylogeographic lineages of South African origin invading France, one originating from northern South Africa and Rooikrantz Dam and the other originating from the southwestern Cape. Given the relative isolation of the Belgian pond, the abundance of Xenopus laevis in the pond, and the presence of tadpoles as well as subadults and large adults, it is certain that X. laevis has been present since several years. Most likely surrounding streams and ponds are also housing them and the area needs to be monitored closely in the future to prevent further spread. Citation: Pauwels, O.S.G., Brecko, J., Baeghe, D., Venderickx, J., Backeljau, T. & Vanderheyden, A. 2024. Morphological, acoustic and genetic identification of a reproducing population of the invasive African clawed frog Xenopus laevis (Anura, Pipidae) recently discovered in Belgium. Abstract 248 in: ICAIS 2024 Abstracts of Presentations. 23rd International Conference on Aquatic Invasive Species, May 12-16, Halifax, Canada.
Located in
Library
/
RBINS Staff Publications 2024
-
Biodiversity hotspots of recent freshwater Ostracoda in Brazil
-
Brazil occupies almost half of the surface area of South America and covers different climatic zones, which leads to great ecological diversifications, forming distinct biogeographical areas or biomes. This reflects the megadiversity of Brazilian flora and fauna, including the high level of endemism. A literature review in 1994 recorded 260 species in 53 genera of recent non-marine ostracods from the South America (MARTENS & BEHEN, 1994). Of these, 91 species in 32 genera occurred in Brazil according to a 1998 checklist (MARTENS et al., 1998). Here, we present the results of recent inventories of freshwater ostracods from Brazil, including an overview of the geographical distribution of species. The expeditions of the PELD (Long-term Ecological Research Program in the Upper Paraná River Floodplain) and SISBIOTA (National Biodiversity Research System program - carried out in four Brazilian floodplains), increased these numbers to 133 species in 41 genera, including the descriptions of 31 new species in nine new genera (e.g. FERREIRA et al., 2020; ALMEIDA et al., 2023). The highest richness of ostracods has been found in the Atlantic Forest biome, which includes the upper Paraná River floodplain. The Amazon biome, where the Amazon floodplain is located, had the lowest diversity of ostracods but has also received much less attention in recent decades: the upper Paraná River floodplain has almost continuously been monitored since 2004, while only two (2011 and 2012), relatively short, collecting trips have been made in the Amazon floodplain. Thus, these results emphasize the relevance of long-term biodiversity monitoring studies. In addition, our results show that there is still little knowledge about the biodiversity of Brazilian ostracods, given that extensive areas remain unexplored.
Located in
Library
/
RBINS Staff Publications 2024
-
Integration of genetic connectivity and local adaptation in the design of marine protected area in the Southern Ocean: a case study opf Trematomus fishes
-
Polar ecosystems harbour a unique cold-adapted biodiversity that is threatened by rapid environmental change and increasing anthropogenic impact. In this context, multi-scale data on connectivity and adaptation are essential for supporting exploitation and conservation management of living resources and ecosystems. Notably, marine protected areas are most effective if implemented as a network that considers functional diversity and connectivity within and between species. In the present study, 607 individuals of ten Trematomus species were sequenced using ddRAD sequencing techniques. Thousands of genomic variants were used to investigate inter- and intraspecific patterns of divergence and connectivity across the Southern Ocean shelf. Moreover, genomic SNPs that showed evidence of selection (“outlier loci”) were used to explore potential local adaptation of the populations to different environmental conditions. Population structure analyses of four different species (T. loennbergii, T. eulepidotus, T. scotti and T. newnesi) suggest long- range dispersal across the Weddell Sea and even along the entire West Antarctic coast that might be facilitated by the Weddell Sea Gyre and Antarctic Coastal current. A genetic break at the level of the Filchner Trough was observed in several species. The strong outflow from the Filchner-Ronne ice shelf may separate the trough area from the remaining Weddell Sea habitat. Finally, results suggest that previously undetected cryptic diversity may be present within T. eulepidotus and T. loennbergii. Altogether, the present results contribute to the assessment of diversity, connectivity and adaptation on the Southern Ocean shelf, which is imperative in view of unprecedented global change.
Located in
Library
/
RBINS Staff Publications 2024
-
COnservation management of POlar ecosystems (COPE project): using genomic approaches to study connectivity in Antarctic fishes and amphipods, across spatial and functional scales
-
The unique cold-adapted ecosystems of the Southern Ocean are threatened by rapid environmental change and increasing anthropogenic impact. Marine protected areas (MPAs), areas of ocean where human activities are limited or prohibited, have been increasingly promoted as a tool for mitigating ocean threats and conserving biodiversity. National governments and the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) is progressing towards establishing a representative network of MPAs in the Southern Ocean. Connectivity is now widely recognized to be a crucial variable for the design and management of MPA networks through the effects that movements of individuals and genes have on population viability, metapopulation persistence, and resilience to disturbance. The understanding of connectivity patterns is required to prioritize the allocation of conservation effort towards, for instance, areas acting as central connection nodes in a network of MPAs. The COPE project aims to advance the understanding of genetic connectivity and adaptation in key benthic and pelagic Antarctic organisms (crustaceans and actinopterygian fishes) using population genomic approaches (ddRAD sequencing). Thousands of genomic variants were used in two model genera, the Charcotia amphipod and the Trematomus fishes, to provide estimates of neutral and adaptive genetic variation and structure at different trophic levels and at a circumpolar scale. The results of the COPE project will contribute to our understanding of the spatial and functional distribution of biological variation in the Southern Ocean, required to develop suitable management and conservation strategies through CCAMLR.
Located in
Library
/
RBINS Staff Publications 2024
-
Genetic connectivity of Trematomus fishes in the Southern Ocean
-
Polar ecosystems harbour a unique cold-adapted biodiversity that is threatened by rapid environmental change and increasing anthropogenic impact. In this context, collecting data on connectivity between populations is essential for supporting conservation management of living resources and ecosystems. Genetic connectivity is the extent to which populations in different parts of a species' geographical range are linked by the exchange of larvae, juveniles or adults (which are the vectors of genetic material). In the Southern Ocean, several Marine Protected Areas (MPAs) – large areas where human activities are restricted or prohibited to promote conservation – are established or under negotiations. Such MPAs are most effective if implemented as a network that considers genetic diversity and connectivity within and between species. In the present study, 607 individuals of ten Trematomus species were sequenced using reduced representation sequencing techniques. Thousands of genomic variants were used to investigate inter- and intraspecific patterns of divergence and connectivity across the Southern Ocean shelf. Population structure analyses of four different species (T. loennbergii, T. eulepidotus, T. scotti and T. newnesi) suggest long- range dispersal across the Weddell Sea and even along the entire West Antarctic coast that might be facilitated by the Weddell Sea Gyre and Antarctic Coastal current. A genetic break at the level of the Filchner Trough was observed in several species. The strong outflow from the Filchner-Ronne ice shelf may separate the trough area from the remaining Weddell Sea habitat. Finally, results suggest that previously undetected cryptic species may be present within both T. eulepidotus and T. loennbergii. Altogether, the present results contribute to the assessment of diversity and connectivity on the Southern Ocean shelf, which is imperative in view of unprecedented global change.
Located in
Library
/
RBINS Staff Publications 2024
-
Is Antarctica an evolutionary incubator? Phylogenetic comparative study of the amphipod family Iphimediidae on the Antarctic shelf
-
Around 40 million years ago, Antarctica’s geographic isolation led to a dramatic cooling of its marine shelf, causing many lineages to go extinct whilst others adapted and flourished. Among the successful ones is the amphipod family Iphimediidae. Here, we apply advanced phylogenetic, comparative, and morphometric methods to explore the evolutionary processes which generated the exceptional diversity of this clade. To this purpose, three types of data were collected: (1) a novel phylogeny of the family was reconstructed from a multigene molecular dataset, (2) 3D shape data were obtained by applying geometric morphometric methods on micro-CT scans, and (3) stable isotope ratios (δ13C and δ15N) were measured and used as proxy for trophic ecology. First, possible evolutionary correlations between mouthpart shapes and stable isotope ratios were examined. Significant correlations suggest that mouthpart shapes are adapted to the food source. Second, species boundaries were investigated using a combination of DNA-based delimitation methods and detailed morphological/morphometric analyses, revealing that Iphimediidae species diversity is greatly underestimated. Most described species were found to be complexes of multiple, morphologically similar species. Finally, changes in lineage diversification rates were explored alongside the evolution of morphological traits. Late bursts of lineage diversification (appr. 7-3 Mya) combined with a late partitioning of mouthparts’ shape diversity might result from the invasion of novel ecological niches. Plio-Pleistocene glacial cycles, which have been hypothesized to act as a diversity pump, might also have promoted such late diversification events in Antarctic iphimediids. This integrative approach, applied here for the first time in Antarctic invertebrates, enhances our understanding of the evolutionary dynamics shaping Antarctic shelf biodiversity.
Located in
Library
/
RBINS Staff Publications 2024
-
Is Antarctica an evolutionary incubator? Phylogenetic comparative study of the amphipod family Iphimediidae on the Antarctic shelf
-
Around 40 million years ago, Antarctica’s geographic isolation led to a dramatic cooling of its marine shelf, causing many lineages to go extinct whilst others adapted and flourished. Among the successful ones is the amphipod family Iphimediidae. Here, we apply advanced phylogenetic, comparative, and morphometric methods to explore the evolutionary processes which generated the exceptional diversity of this clade. To this purpose, three types of data were collected: (1) a novel phylogeny of the family was reconstructed from a multigene molecular dataset, (2) 3D shape data were obtained by applying geometric morphometric methods on micro-CT scans, and (3) stable isotope ratios (δ13C and δ15N) were measured and used as proxy for trophic ecology. First, possible evolutionary correlations between mouthpart shapes and stable isotope ratios were examined. Significant correlations suggest that mouthpart shapes are adapted to the food source. Second, species boundaries were investigated using a combination of DNA-based delimitation methods and detailed morphological/morphometric analyses, revealing that Iphimediidae species diversity is greatly underestimated. Most described species were found to be complexes of multiple, morphologically similar species. Finally, changes in lineage diversification rates were explored alongside the evolution of morphological traits. Late bursts of lineage diversification (appr. 7-3 Mya) combined with a late partitioning of mouthparts’ shape diversity might result from the invasion of novel ecological niches. Plio-Pleistocene glacial cycles, which have been hypothesized to act as a diversity pump, might also have promoted such late diversification events in Antarctic iphimediids. This integrative approach, applied here for the first time in Antarctic invertebrates, enhances our understanding of the evolutionary dynamics shaping Antarctic shelf biodiversity.
Located in
Library
/
RBINS Staff Publications 2024
-
Integrating genetic connectivity and local adaptation in effective Marine Protected Area design: a case study on Southern Ocean Trematomus fishes.
-
Polar ecosystems support a distinctive, cold-adapted biodiversity that faces significant threats from rapid environmental changes and escalating human impacts. To effectively manage and conserve these living resources, multi-scale data on connectivity and adaptation are essential. Marine protected areas (MPAs) are most effective when designed as interconnected networks that account for both functional diversity and connectivity within and among species. In this study, 607 individuals from ten Trematomus species were analyzed through ddRAD sequencing, yielding thousands of genomic markers to examine patterns of divergence and connectivity on the Southern Ocean shelf, both within and between species. Genomic SNPs showing evidence of selection, identified as "outlier loci," were further analyzed to explore potential local adaptations to varying environmental conditions. Population structure analyses of four species — T. loennbergii, T. eulepidotus, T. scotti, and T. newnesi — indicate extensive dispersal across the Weddell Sea and along the West Antarctic coast, likely facilitated by the Weddell Sea Gyre and the Antarctic Coastal Current. A genetic discontinuity was detected near the Filchner Trough in several species, likely due to the strong outflow from the Filchner-Ronne ice shelf, which may isolate the trough region from the broader Weddell Sea habitat. Additionally, evidence of previously unrecognized cryptic diversity was observed in T. eulepidotus and T. loennbergii. These findings contribute to our understanding of diversity, connectivity, and adaptation on the Southern Ocean shelf, a critical foundation for conservation amid unprecedented global change.
Located in
Library
/
RBINS Staff Publications 2024
-
Les sinusites maxillaires à l’époque mérovingienne. Étude des nécropoles de Ciply, Braives et Torgny (Belgique, VIe-VIIe siècles ap. J.-C.)
-
Les sinusites maxillaires chroniques font actuellement partie des pathologies respiratoires les plus communes. Les modifications des parois osseuses qu’elles entrainent peuvent être observées dans les populations du passé permettant ainsi d’apporter de précieux éléments sur leur santé respiratoire. Ces dernières années, plusieurs auteurs ont étudié les sinusites dans des populations médiévales européennes mais aucune recherche n’avait encore porté sur la période mérovingienne. Notre étude comble cette lacune en analysant trois populations de Belgique datées des VIe-VIIe siècles : Ciply, Braives et Torgny. L’échantillon total s’élève à 145 individus pour lesquels au moins une paroi sinusienne complète était visible à l’œil nu. Les sinus maxillaires ont été analysés selon la méthode développée par Boocock et collaborateurs en 1995. Quatre critères de changement osseux ont ainsi été enregistrés : le type, le degré de développement, l’étendue et la sévérité des lésions. Au total, 143 individus présentaient des modifications osseuses, soit un taux de prévalence de 98,6 %. Celui-ci est très élevé par rapport aux fréquences observées dans des populations actuelles (de 7,5 à 66 %). Il est également supérieur à ce qui a été relevé dans les populations anciennes même si deux échantillons du Bas Moyen Âge (suédois et belge) ont livré des prévalences qui dépassent les 90 %. La rudesse du climat, le mode de vie et l’état sanitaire en Belgique au Haut Moyen Âge pourraient expliquer ce résultat extrême. Au sein de notre échantillon, aucune différence de sévérité n’a été observée en fonction de l’origine géographique ou du sexe. En revanche, le groupe plus âgé présente des atteintes significativement plus sévères. Ceci pourrait résulter d’un effet cumulatif de la maladie ou d’une plus grande fragilité des aînés. Notre étude apporte sa contribution à la connaissance de l’état sanitaire des populations mérovingiennes dont le mode de vie est principalement documenté via l’étude de leurs nécropoles
Located in
Library
/
RBINS Staff Publications 2024
-
Base du crâne, labyrinthe osseux et dimorphisme sexuel : investigation morphométrique au sein d’un échantillon d’Europe de l’Ouest
-
L’estimation du sexe biologique d’un individu constitue une étape primordiale de l’analyse anthropologique, que ce soit en contexte archéologique ou forensique. Elle doit se fonder sur des méthodes de diagnose sexuelle reproductibles, fiables et validées. Néanmoins, cette tâche peut s’apparenter à un véritable défi lorsque la préservation des éléments diagnostiques osseux n’est pas optimale, et ce d’autant plus s’il s’agit de restes immatures ou brûlés. Face à de tels restes fragmentés, une voie prometteuse consisterait à mettre en place une méthode de diagnose sexuelle s’appuyant sur un élément osseux à la fois fortement dimorphique et à la survie taphonomique avérée. Alliant ostéométrie et outils digitaux au travers d’une approche strictement morphométrique, cette recherche propose d’évaluer le dimorphisme de la base du crâne (i.e., os occipital et temporaux) et celui du labyrinthe osseux de l’oreille interne sur un assemblage osseux comprenant 611 crânes et 121 labyrinthes appartenant à des sujets européens – immatures et adultes – d’âge et de sexe connus. Les résultats obtenus dans cette étude démontrent d’une part que le dimorphisme sexuel de l’os temporal est plus marqué que celui de l’os occipital, et ce dès la phase pubertaire, et d’autre part qu’il n’est pas possible d’établir une méthode de diagnose sexuelle indépendante de l’âge sur le labyrinthe osseux du fait des différences d’expression de son dimorphisme sexuel observées entre les immatures et les adultes. En outre, ce travail a permis d’établir plusieurs modèles prédictifs de diagnose sexuelle à partir de la base du crâne adulte (avec de 77 à 87 % de classification correcte), du labyrinthe osseux adulte (de 76 à 83 %) et du labyrinthe immature (de 76 à 84 %). Leurs qualités intrinsèques (i.e., reproductibilité, fiabilité, facilité d’utilisation et faible coût) en font des outils de diagnose sexuelle adaptés à l’examen de restes osseux fragmentaires.
Located in
Library
/
RBINS Staff Publications 2024
