A temporary outcrop near the “Rubenshuis” in the centre of Antwerp (northern Belgium) facilitated the study of the Neogene glauconitic sand of the Berchem and Kattendijk formations, west and south of their respective stratotype sections. In contrast to the latter sections, the exposed Kiel Member of the Berchem Formation contains a relatively silty interval in its upper part, which is also reflected in Cone Penetration Tests. This silty interval is rich in molluscs, including the subspecies Glossus lunulatus cf. lunulatus and Ennucula haesendoncki haesendoncki, previously unknown from this member. Dinoflagellate cysts indicate that the main body of the Kiel Member was deposited during the middle Burdigalian, while only the upper part was deposited during the late Burdigalian. The Kiel Member is covered by the shell-rich, silty sand of the Langhian Antwerpen Member (Berchem Formation). Both members display soft-sediment deformation structures, probably caused by differences in silt content between and within these units. The Antwerpen Member is incised by the Lower Pliocene Kattendijk Formation, which reduced the thickness of the former to only 1.1 m, compared to 7 m in northeastern Antwerp. As a result, the basal gravel of the Kattendijk Formation contains many fossils reworked from the Antwerpen Member, in addition to autochthonous molluscs and Ditrupa. The Zanclean fauna resembles associations known from the highest part of the Kattendijk Formation in the former Oosterweel outcrop north of Antwerp, while it differs from the fauna of the lowermost Kattendijk Formation near Doel and Kallo. Hence, the palaeontological observations corroborate the regional depositional model of this unit, suggesting that only the youngest gully sequence of the Kattendijk Formation was deposited across the city of Antwerp.
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RBINS Staff Publications 2024 OA
In 1909, the famous palaeontologist Louis Dollo announced, in a paper about the Belgian fossil vertebrates, a new Oligocene (Rupelian) genus and species of sea turtle, ‘Oligochelone rupeliensis’. He indicated that it was established for a specimen that preserved the complete carapace and several appendicular bones, being characterized as “a typical marine turtle”. No further information, but neither photographs or drawings, were provided by him. He planned to publish the study of this species in the future, but this did not happen. Only a schematic drawing of the plastron of that specimen, as well as a photograph of a tibia attributed to this taxon without justification, were presented, by another author, seventy years later. The first-hand study of the specimen considered by Dollo allows us to observe that it does not preserve any tibia, so that attribution cannot be supported. Therefore, except for that imprecise drawing of the plastron published more than four decades ago, no additional information was available so far. In fact, ‘Oligochelone rupeliensis’ was recognized as a nomen nudum. After a preliminary analysis of the specimen considered by Dollo, one of us (APG) and other collaborators recently indicated, without justification, that, although ‘Oligochelone rupeliensis’ could be closely related to the Eochelone representatives, it differs from all defined members of Cheloniidae. Therefore, we point out that a detailed anatomical study of this form, as well as its comparison with other species, would be necessary to propose, for the first time, a diagnosis, if its specific validity can be confirmed. Taking this into account, that partial skeleton has been analyzed in detail by us. To improve the comparative framework, both the type material and additional individuals from all Eocene and Oligocene cheloniid taxa recognized for the Belgian record have also been analyzed first-hand. The preliminary results are presented here.
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RBINS Staff Publications 2025
