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Communication Dans Un Congrès Année : 2024

Phosphate fossilization in Quercy: Revealing the exceptional preservation of reproductive organs

Yiyun Chen
  • Fonction : Auteur
  • PersonId : 1388529
Anais A Boura

Résumé

The Quercy phosphorites have long been renowned for their diverse fossil vertebrate fauna, which were used to characterize the “grande coupure” at the Eocene/Oligocene boundary. This boundary is linked with an abrupt cooling climate, profoundly altering the vegetation. In this unique paleokarstic context, typically associated with vertebrate mineralization, the fossilization process has yielded mineralized (phosphate-enriched) plants exhibiting a distinctive appearance. This study focuses on the exceptional preservation of fossilized plant specimens, including flower buds, fruits, and seeds, found in the Quercy region. These fossils have occurred under unusual terrestrial circumstances, enabling them to preserve fine, high-resolution visible anatomical structures. The research effort involved the selection of over 800 well-preserved plant fossil samples, spanning the late Eocene to early Oligocene periods. Notably, the collection includes several flower bud fossils and a substantial number of Vitaceae and Anacardiaceae fruit and seeds. The study is based on the employment of micro-CT scanning for high-resolution reconstruction as well as anatomical slides. They reveal distinct morphotypes among the flower bud samples, such as trimerous, tetramerous, and pentamerous structures. The stamens and gynoecia are, in particular, perfectly preserved. The internal structures of the analyzed fruits show that they belong to the fruit types capsules and drupes. Additionally, this research confirms the identification of Anacardiaceae at the genus level (Pentoperculum) and identifies two morphotypes within Vitaceae, potentially linked to Vitis or closely relatedXV International Palynological Congress & XI International Organization of Palaeobotany Conference, 27–31 May, 2024, Prague, Czech Republic 159 genera. The unique preservation characteristics of phosphate fossils are highlighted, emphasizing their utility in preserving internal structures. The application of micro-CT with high resolution enhances species identification. Overall, the findings underscore the significance of Quercy phosphorites as an invaluable source for advancing our understanding of ancient ecosystems and plant evolution. This not only contributes to paleodiversity reconstructions but also aids in systematic phylogenetic studies.
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Dates et versions

hal-04598560 , version 1 (03-06-2024)

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  • HAL Id : hal-04598560 , version 1

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Yiyun Chen, Cédric Del Rio, Anais A Boura. Phosphate fossilization in Quercy: Revealing the exceptional preservation of reproductive organs. XV International Palynological Congress & XI International Organization of Palaeobotany Conference, May 2024, Prague (CZ), Czech Republic. ⟨hal-04598560⟩
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