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Communication Dans Un Congrès Année : 2023

Fossil endocarps of Menispermaceae from the late Paleocene of Paris Basin, France

Résumé

Menispermaceae are an angiosperm family of mostly climbing plants distributed throughout tropical regions. The fruits in this family have a distinctively curved, strong sclerified endocarp and can be used for reliable species-level identifications, even in a fossilized form. New Paleocene-age menispermaceous endocarps have recently been discovered in South America and Asia, while in Europe, they are mostly found in the Eocene. The presentation focuses on the study of fossil endocarps belonging to Menispermaceae, found in the Petit-Pâtis locality (Rivecourt, France), which is one of the few Paleocene localities in Europe. The locality is dated to the late Paleocene (57–56 Ma) and the fossils represent flora and fauna in the Paris Basin just before the onset of the Paleocene-Eocene Thermal Maximum. Lignitised fossils were photographed and their anatomy was analysed using computed tomography, scanning electron microscope and geometric morphometric analysis. The analysis of thirty-six fossils belonging to Menispermaceae revealed that three genera (Stephania Lour., Palaeosinomenium Reid & Chandler, Tinospora Miers) were present in the Late Paleocene of Paris Basin. Despite a new combination of characters (pyriform shape, one lateral crest, and 15-19 lateral ridges, presence of a foramen in the central area), the Stephania specimen is considered as unresolved at the species level. Differences in internal anatomy and a more inflated endocarp base led to a description of new species – Palaeosinomenium oisensis. Finally, a new occurrence of Tinospora excavata Reid & Chandler is found based on hemispherical endocarps with a small ventral opening and tuberculate externally. The occurrence of these genera in the Paleocene of France is consistent with the suggestions that megathermal flora was present in the Paris Basin before the Paleocene-Eocene Thermal Maximum. These three genera are currently the oldest occurrences in Europe, highlighting the connection between paleofloras of the Americas, Europe and Asia in the Paleocene.
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Dates et versions

hal-04202706 , version 1 (11-09-2023)

Identifiants

  • HAL Id : hal-04202706 , version 1

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Eliise Kara, Jérémie Bardin, Dario De Franceschi, Cédric Del Rio. Fossil endocarps of Menispermaceae from the late Paleocene of Paris Basin, France. 8th Agora Paleobotanica Meeting, Sep 2023, Bellver de Cerdanya, Spain. ⟨hal-04202706⟩
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