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Inproceedings Reference Updating the theories on ammonoid extinction
Since Alvarez et al. (1980) found new evidence for the impact of catastrophic events on earth’s biota, hypothesis and theories explaining the fossil record (re)gained a lot of attention. The extraterrestrial origin of the anomalous iridium concentrations seemed highly controversial at first, but nowadays the Chicxulub ‘accident’ has become the marker for the start/base of the Paleogene. Its pivotal role in the Mesozoic-Cenozoic faunal turnover cannot be refuted (Schulte et al 2010). However, alternative theories remain being published. Of these, the Deccan volcanism with its widespread flood basalts stepped prominently forward as one of the main triggers, especially when trying to explain the gradual diversity decline within the fossil record. The inconsistencies between the proposed theories generally root in too narrowly geographically and geologically spread datasets. This applies to most fossil groups, and especially to the ammonoids (Class Cephalopoda, °Early Devonian – †Late Cretaceous). A compilation of ammonoid occurrences of Late Maastrichtian age published by Kiessling & Claeys (2002) evidenced the lack of a globally well distributed dataset. In this compilation, North Africa was left as a blind spot, while Tunisia had been the centre of the K/Pg mass extinction debate for almost three decades, e.g. with the definition of the GSSP for the base of the Paleogene at El Kef. Both at the GSSP and several other sections in the Tunisian Trough Basin, ammonoids were found within the topmost meters of the Maastrichtian, until very close to the K/Pg boundary level. About 900 uppermost Maastrichtian ammonoids were collected, all from within the last 420.000 years of the Cretaceous. With 22 species on record, belonging to 18 genera and 10 families, and with representatives of each of the four large ammonoid suborders (Phylloceratina, Lytoceratina, Ammonitina and Ancyloceratina), the Tunisian fauna demonstrates that ammonoids were both taxonomically and morphologically diverse until their very end. An updated version of the compilation of latest Maastrichtian ammonoid occurrences documents at least 53 species, 29 genera and 13 families in the ultimate half million year of the Cretaceous, in many more localities and occurring in a wide variety of settings. When the Tunisian ammonoid species richness data are plotted next to all time constraints of the possible causes, the possibility of Deccan flood basalt volcanism negatively influencing ammonoid diversity must be refuted. A major extinction caused by the Chicxulub impact seems the most plausible theory at present. Through inducing a mass kill of the marine plankton, the juvenile ammonoids lost their primary food source leading to their final extinction. Alvarez, L.W., Alvarez, W., Asaro, F., Michel, H.V., 1980. Extraterrestrial cause for the Cretaceous-Tertiary extinction. Science, 208, 1095-1108. Kiessling, W., Claeys, P., 2002. A geographic database approach to the KT Boundary. In Buffetaut, E., Koeberl, C. (Eds), Geological and Biological Effects of Impact Events, Springer-Verlag Berlin, 83-140. Schulte, P. & 40 authors, 2010. The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary. Science 327, 1214-1218.
Located in Library / RBINS Staff Publications
Article Reference Use of Soil and Litter Ants (Hymenoptera: Formicidae) as Biological Indicators of Soil Quality Under Different Land uses in Southern Rwanda
Located in Library / RBINS Staff Publications 2018
Inproceedings Reference Using DNA barcodes for assessing diversity of dance flies (Diptera: Empidoidea) and as a basis for phylogenetic research
Located in Library / RBINS Staff Publications
Proceedings Reference Using DNA barcodes for diversity assessment in Hybotidae (Diptera, Empidoidea)
Located in Library / RBINS Staff Publications
Inproceedings Reference Utilisation des propriétés antigéniques du collagène dans la détermination taxonomique de l'os
Located in Library / RBINS Staff Publications
Article Reference Van wolf tot woef
Located in Library / RBINS Staff Publications
Inproceedings Reference Varanidé, Saniwa orsmaelensis, de l'Eocène basal du Nord-Ouest de l'Europe
Saniwa est un genre éteint de lézard varanidé de l’Eocène européen et nord-américain et taxon frère du groupecouronne Varanus. Jusqu’à maintenant, seule une espèce, Saniwa orsmaelensis était rapportée en Europe, dans l’Eocène basal de Dormaal, Belgique. Cette espèce, originellement nommée par Louis Dollo il y a presqu’un siècle, est le plus ancien varanidé d’Europe. Malheureusement, le matériel diagnostique était limité à quelques vertèbres, décrites assez brièvement et non figurées, si l’on excepte une vertèbre dorsale désignée comme lectotype. Nous décrivons et illustrons ici de nouveaux spécimens de Dormaal ainsi que du Quesnoy, Bassin de Paris, France, incluant des restes crâniens (maxillaire, dentaires et pariétal), permettant de confirmer la validité de ce taxon européen. Ces nouveaux spécimens permettent en effet de nouvelles comparaisons avec l’espèce-type Saniwa ensidens, de l’Eocène moyen des formations de Bridger et de Green River, Wyoming, Etats-Unis et permettent d’amender la diagnose de S. orsmaelensis. La présence de S. orsmaelensis est restreinte à l’Eocène inférieur du Nord-Ouest de l’Europe et son origine géographique n’est pas encore certaine car Saniwa apparait simultanément en Amérique du Nord en Europe. La présence relativement brève des lézards varanidés dans le Paléogène Européen pourrait résulter des rapides changements environnementaux aux alentours du Paleocene Eocene Thermal Maximum qui ont permis de nombreux échanges fauniques dans l’hémisphère nord. Cependant, le sens de ces migrations n’est pas encore connu. Par ailleurs, les considérations paléogéographiques liées à la distribution du genre Saniwa suggèrent une origine asiatique bien qu’une origine africaine ne puisse être complètement exclue. Ce résumé est une contribution au projet réseau Belspo Brain BR/121/A3/PalEurAfrica financé par le Bureau de la Politique Scientifique Belge.
Located in Library / RBINS Staff Publications 2019
Article Reference Verstekelingen met een geurtje in de bosmierennesten van De Haan
Located in Library / RBINS Staff Publications
Article Reference Vertebrate predation in the Late Devonian evidenced by bite traces and regurgitations: implications for an early tetrapod freshwater ecosystem
The terrestrialization process by vertebrates occurred during the Devonian period, with fully land-dwelling tetrapods recorded in the Carboniferous. Thus, the Late Devonian is an important period for deciphering the ecological pressures that applied during the water-to-land transition. Higher predation pressures in the underwater environment have been suggested as an influential biotic evolutionary factor in this key habitat shift. Direct evidence of ancient predation on Palaeozoic vertebrates is seen in the form of rare traces preserved on fossils, and these range from trauma observed on the skeleton (such as attack marks) to ingested food remains (bromalites). The late Famennian freshwater ecosystem of Strud (Belgium) consists of a rich assemblage of many coeval gnathostomes or jawed fishes (placoderms, ‘acanthodians’, actinopterygians, and various sarcopterygian groups including tetrapods). Here we analyse the record of direct evidence for predation in the Strud vertebrate fossil assemblage. We recognize 12 regurgitalites and 13 bite traces, including a rare case of a tooth embedded in its original prey body target. Fossils from regurgitalites were imaged using scanning electron microscopy and chemically analysed to test for their possible ingestion signature by comparison with other isolated skeletal remains from the same locality. From this evidence, tristichopterid tetrapodomorphs are inferred to be the highest consumers of the trophic network, targeting small placoderms, and porolepiforms, and probably congeners. We observe two possible prey patterns in regurgitalites, for sarcopterygians and actinopterygians, both of which are associated with acanthodians. In Strud, no trophic position can be deduced for tetrapods from direct fossil evidence of predation.
Located in Library / RBINS Staff Publications 2022
Inproceedings Reference Vestibular sensitivity and locomotor behavior in early paleocene mammals
The end-Cretaceous extinction triggered the collapse of ecosystems and a drastic turnover of mammalian communities. During the Mesozoic, mammals were ecologically diverse, but less than extant species. Modern ecological richness was established by the Eocene, but questions remain about the ecology of the first wave of mammals radiating after the extinction. Postcranial fossils are often used to determine locomotor behavior; however, the semicircular canals of the inner ear also represent a reliable proxy. These canals detect the angular acceleration of the head during locomotion and transmit neuronal signals to the brain to allow stabilization of the eyes and head. Accordingly, vestibular sensitivity to rapid rotational head movements is higher in species with a larger canal radius of curvature and more orthogonal canals. We used high-resolution computed tomography scanning to obtain inner ear virtual endocasts for 30 specimens. We supplemented these with data from the literature to construct a database of 79 fossils from the Jurassic to the Eocene and 262 extant mammals. We compared data on canal morphology and another lifestyle proxy, the size of the petrosal lobules, which have a role in maintaining eyes’ movements and position. We find that Paleocene mammals exhibited a lower average and more constricted range of Agility Indices (AI), a new measure of canal radius size relative to body size, compared to Mesozoic, Eocene and extant taxa. In the early Paleocene, body mass and canal radius increased, but the former outpaced the latter leading to an AI decline. Similarly, their petrosal lobules were relatively smaller on average compared to other temporal groups, which suggests less ability for fast movements. Additionally, Paleocene mammals had similar AIs to extant scansorial and terrestrial quadrupeds. In contrast, the lack of canal orthogonality change from the Mesozoic to the Paleocene indicates no trend toward lower vestibular sensitivity regardless of changes in body size. This result may reflect functional differences between canal orthogonality and radius size. Our results support previous work on tarsal morphology and locomotor behavior ancestral state reconstruction suggesting that ground dwelling mammals were more common than arboreal taxa during the Paleocene. Ultimately, this pattern may indicate that the collapse of forested environments immediately after extinction led to the preferential survivorship of more terrestrially adapted mammals. Funding Sources Marie Sklodowska-Curie Actions: IF, European Research Council StG, National Science Foundation, Belgian Science Policy Office, DMNS No Walls Community Initiative.
Located in Library / RBINS Staff Publications 2022 OA