Search results

Nearly every geological subdiscipline relies to some degree on regional geological knowledge. In the introductory section of most geological papers it is standard practice to provide regional geological background information. Stratigraphic terminology is often well defined while other disciplinary concepts rely, at least to some degree, on generally agreed definitions or hierarchical schemes, such as paleontological, structural or magmatic terminology. This, however, is much less the case for the regional geological building blocks. Their names are usually composed of a combination of a geographical locality and a geological term. A few examples from Belgium are Brabant Massif, Campine Basin, Stavelot-Venn Inlier, and Malmedy Graben. Most of these have in common that, although their importance is well recognised, their definitions are vague and sometimes even conflicting, in that their meaning may differ between contexts and authors. Even if their meaning has drifted or become less exact, as a result of their frequent historical use, they commonly remain in use today. This issue is not exclusive to Belgium, but seems to be an altogether historic and worldwide phenomenon. Recently within Europe there is a growing awareness of this issue, resulting in important but rather isolated efforts to better structure and define regional information (Hintersberger et al. 2017; Németh 2021; Le Bayon et al. 2022) which have been brought together through pan-European cooperation (GSEU – Horizon Europe 101075609). The central element that seems to encompass most geologic features, is the lithotectonic unit (a distinct unit based on its partly separate geological history; URI: http://inspire.ec.europa.eu/codelist/GeologicUnitTypeValue/lithotectonicUnit). Grabens, basins and inliers are examples of lithotectonic units. In order to define and describe these units more accurately, lithotectonic limits are introduced. These are planar features, such as faults and unconformities, that correspond to the geologic events that formed the lithotectonic unit (Piessens et al. 2024). All information is organised and linked in vocabularies (thesauri) that together not only adequately define each concept, but also determine the relations between them, placing them in space and geological time (Plašienka 1999). This outlines the core methodology, around which 2D and 3D multi-scale visualisations are built, annotations can be added, existing ontologies can be linked (such as the ICS Geological Time Scale Ontology; Cox and Richard, 2005) and newly developed extensions such as the Modified Wilson Cycle (Németh 2021). As such, the work at Belgian level is closely linked to the ongoing international developments. Making use of the ongoing developments at European level, Belgium was the first country to set up a lithotectonic working group that became operational in 2023. Its first goal is to provide a lithotectonic framework that describes a starting set of main geological units and limits in Belgium, according to emerging European standards (the work at European level is linked to the implementation of INSPIRE and 195 is in communication with the GeoSciML community), by the end of 2024. The working group meets approximately every 2 months, and organisationally resides under the National Commission for Stratigraphy in Belgium. The working group will soon be looking for additional experts (junior and senior) in its continuing effort to identify and define broad superstructures, detail the regional geology to the more local level, to tackle new types of lithotectonic elements, or better address parts of geological history. Potential candidates are encouraged to contact one of the authors or the NCS secretariat. Cox SJD, Richard SM (2005) A formal model for the geologic time scale and global stratotype section and point, compatible with geospatial information transfer standards. Geosphere 1:119. https://doi.org/10.1130/GES00022.1 Hintersberger E, Iglseder C, Schuster R, Huet B (2017) The new database “Tectonic Boundaries” at the Geological Survey of Austria. Jahrbuch der geologischen Bundesanstalt 157:195–207 Le Bayon B, Padel M, Baudin T, et al (2022) The geological-event reference system, a step towards geological data harmonization. BSGF - Earth Sci Bull 193:18. https://doi.org/10.1051/bsgf/2022017 Németh Z (2021) Lithotectonic units of the Western Carpathians: Suggestion of simple methodology for lithotectonic units defining, applicable for orogenic belts world-wide. Mineralia Slovaca 2:81–90 Piessens K, Walstra J, Willems A, Barros R (2024) Old concepts in a new semantic perspective: introducing a geotemporal approach to conceptual definitions in geology. Life Sciences Plašienka D (1999) Definition and correlation of tectonic units with a special reference to some Central Western Carpathian examples. Mineralia Slovaca 31:3–16

We report a case of predation by an adult Eastern Black-and-Yellow Tree Snake Toxicodryas vexator (Serpentes : Colubridae) on a juvenile Lord Derby's Scaly-tailed Squirrel Anomalurus derbianus (Rodentia : Anomaluridae) in Yangambi, Tshopo Province, Democratic Republic of the Congo. This is the first documented interaction between these two species.

Caecilians are elongate, limbless and annulated amphibians that, with the exception of one aquatic family, all have an at least partly fossorial lifestyle. It has been suggested that caecilian evolution resulted in sturdy and compact skulls with fused bones and tight sutures, as an adaptation to their head-first burrowing habits. However, although their cranial osteology is well described, relationships between form and function remain poorly understood. In the present study, we explored the relationship between cranial shape and in vivo burrowing forces. Using micro-computed tomography (µCT) data, we performed 3D geometric morphometrics to explore whether cranial and mandibular shapes reflected patterns that might be associated with maximal push forces. The results highlight important differences in maximal push forces, with the aquatic Typhlonectes producing a lower force for a given size compared with other species. Despite substantial differences in head morphology across species, no relationship between overall skull shape and push force could be detected. Although a strong phylogenetic signal may partly obscure the results, our conclusions confirm previous studies using biomechanical models and suggest that differences in the degree of fossoriality do not appear to be driving the evolution of head shape.

Large tropical trees are rightly perceived as supporting a plethora of organisms. However, baseline data about the variety of taxa coexisting on single large tropical trees are lacking and prevent a full understanding of both the magnitude of biodiversity and the complexity of interactions among organisms in tropical rainforests. The two main aims of the research program “Life on Trees” (LOT) are (1) to establish baseline knowledge on the number of eukaryote species supported/hosted by the above-ground part of a single tropical tree and (2) to understand how these communities of organisms are assembled and distributed on or inside the tree. To achieve the first goal, we integrated a set of 36 methods for comprehensively sampling eukaryotes (plants, fungi, animals, protists) present on a tropical tree. The resulting LOT protocol was conceived and implemented during projects in the Andean Amazon region and is proposed here as a guideline for future projects of a similar nature. To address the second objective, we evaluated the microclimatic differences between tree zones and tested state-of-the-art terrestrial laser scanning (TLS) and positioning technologies incorporating satellite and fixed base station signals (dGNSS). A marked variation in temperature and relative humidity was detected along a 6-zones Johansson scheme, a tree structure subdivision system commonly used to study the stratification of epiphytic plants. Samples were collected from these six zones, including three along the trunk and three in the canopy. To better understand how different tree components (e.g., bark, leaves, fruits, flowers, dead wood) contribute to overall tree biodiversity, we categorized observations into communities based on Johansson zones and microhabitats. TLS was an essential aid in understanding the complex tree architecture. By contrast, the accuracy of positioning samples in the tree with dGNSS was low. Comprehensively sampling the biota of individual trees offers an alternative to assessing the biodiversity of fewer groups of organisms at the forest scale. Large old tropical trees provide a wealth of microhabitats that encompass a wide range of ecological conditions, thereby capturing a broad spectrum of biodiversity.

We here provide a detailed description of the vertebral morphology of the African arboreal viperid snakes of the genus Atheris. Vertebrae of three different species of the genus, i.e., Atheris desaixi, Atheris hispida, and Atheris katangensis, were investigated via the aid of μCT (micro‐computed tomography) scanning. We describe several vertebrae from different regions of the vertebral column for all three species, starting from the atlas‐axis complex to the caudal tip, in order to demonstrate important differences regarding the intracolumnar variation. Comparison of these three species shows an overall similar general morphology of the trunk vertebrae among the Atheris species. We extensively compare Atheris with other known viperids. As the sole arboreal genus of Viperinae the prehensile nature of the tail of Atheris is reflected in its caudal vertebral morphology, which is characterized by a high number of caudal vertebrae but also robust and anteroventrally oriented pleurapophyses as a skeletal adaptation, linked with the myology of the tail, to an arboreal lifestyle. We anticipate that the extensive figuring of these viperid specimens will also aid identifications in paleontology.