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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Pipimorpha and its crown-group Pipidae possess one of the most extensive fossil records among anurans, which extends into the Early Cretaceous in both Laurasia and Gondwana. This is probably linked to the highly aquatic lifestyle of pipids, which is probably also characteristic of early pipimorphs. In South America, pipids are currently represented only by Pipa, but the fossil record documents an evolutionary radiation of Shelaniinae (a taxon endemic to South America) in the Cretaceous; shelaniines seem to have become extinct in the Eocene. Fewer pipimorph fossils are known from Africa. Our recent redescription of the mid-Late Cretaceous (Coniacian–Santonian) taxon Pachycentrata taqueti from In Becetèn (Niger) partly fills this gap. Our new phylogenetic analysis of Cretaceous and Paleogene pipimorphs shows that this taxon diversified in a West Gondwanan block until about the mid-Cretaceous, but after that, pipimorphs show two distinct evolutionary radiations, one in South America (Pipinae), and the other (Xenopodinae) in Africa. This pattern appears to reflect the breakup of West Gondwana simultaneously with the opening of the South Atlantic during the Cretaceous. This probable vicariant pattern yields slightly different ages for the South Atlantic opening depending on the accepted topology. The tree constrained to reflect the topology of extant taxa supported by molecular data shows a last dispersal between both continents before the Cenomanian (more than 100 Ma), whereas the unconstrained topology that reflects only morphological data is compatible with a more recent last faunal dispersal among pipids. Under this unconstrained topology, the fossil record is too poor to give a reliable minimal age for this last dispersal, but molecular dating analyses suggest that this event harks back to the Mesozoic.
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