Publicação
Albanerpetontidae (Lissamphibia) and other small herpetofauna (Crocodylomorpha, Lepidosauria, Choristodera) from the Iberian Mesozoic, with focus on the Upper Jurassic of Portugal
| Resumo: | The Upper Jurassic of Portugal has been globally known for its microfossil vertebrate fauna thanks to the Konzentrat-Lagerstätte of the Guimarota mine, which provided thousands of bone fragments, isolated teeth, and even complete specimens. Other vertebrate microfossil assemblages have been studied around the world. Besides Guimarota, only a handful of other Portuguese Jurassic assemblages has been studied, but never extensively. Hereby, I present my work on microvertebrates from the Lourinhã Formation (Kimmeridgian–Tithonian), with a focus on the small herpetofauna of the Late Jurassic of Portugal. A total of 5,100 vertebrate remains have been identified, belonging to all major vertebrate groups known in other continental and freshwater environments. Stratigraphy and sedimentological analyses of different localities carried in collaboration with Dr. Lope Ezquerro and Dr. Cristina Sequero allowed to draw a first palaeoenvironmental reconstruction, depicting various depositional settings: low sediment supply and long periods of subaerial exposure in Valmitão; area of alternating conditions between wet and dry periods in Zimbral; and wetter conditions, probably associated with permanent sheet of water and anoxic environments in Porto das Barcas. Revision of the Guimarota collection allowed to locate misidentified, mislabelled, and unpublished specimens that could be assigned to Cteniogenys aff. C. antiquus, although different from the material reported in the Middle Jurassic Kirtlington Mammal Beds in the UK; and confirm the presence of a new species of a relic stem-lepidosaur. Overall, the Lourinhã Formation is largely dominated by amphibious vertebrates, more than in other equivalent Mesozoic assemblages around the Jurassic/Cretaceous boundary. Notably, crocodylomorphs shed teeth support a high morphological and ecological diversity of the group; while albanerpetontids remains are quite numerous and diverse in anatomical parts preserved. This allowed to erect the oldest albanerpetontid species from the Iberian Peninsula, and the first of Portugal. Together with another new species , the youngest of the Iberian Peninsula, the new Portuguese material allowed to review the phylogeny of Albanerpetontidae and propose a new hypothesis on their in-group relationship, as well as new insight on their palaeobiogeography at the end of the Cretaceous. |
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| Autores principais: | Guillaume, Alexandre Renaud Daniel |
| Assunto: | Upper Jurassic Vertebrate microfossil assemblages Lourinhã Formation Herpetofauna Albanerpetontidae |
| Ano: | 2024 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade Nova de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório Institucional da UNL |
| Resumo: | The Upper Jurassic of Portugal has been globally known for its microfossil vertebrate fauna thanks to the Konzentrat-Lagerstätte of the Guimarota mine, which provided thousands of bone fragments, isolated teeth, and even complete specimens. Other vertebrate microfossil assemblages have been studied around the world. Besides Guimarota, only a handful of other Portuguese Jurassic assemblages has been studied, but never extensively. Hereby, I present my work on microvertebrates from the Lourinhã Formation (Kimmeridgian–Tithonian), with a focus on the small herpetofauna of the Late Jurassic of Portugal. A total of 5,100 vertebrate remains have been identified, belonging to all major vertebrate groups known in other continental and freshwater environments. Stratigraphy and sedimentological analyses of different localities carried in collaboration with Dr. Lope Ezquerro and Dr. Cristina Sequero allowed to draw a first palaeoenvironmental reconstruction, depicting various depositional settings: low sediment supply and long periods of subaerial exposure in Valmitão; area of alternating conditions between wet and dry periods in Zimbral; and wetter conditions, probably associated with permanent sheet of water and anoxic environments in Porto das Barcas. Revision of the Guimarota collection allowed to locate misidentified, mislabelled, and unpublished specimens that could be assigned to Cteniogenys aff. C. antiquus, although different from the material reported in the Middle Jurassic Kirtlington Mammal Beds in the UK; and confirm the presence of a new species of a relic stem-lepidosaur. Overall, the Lourinhã Formation is largely dominated by amphibious vertebrates, more than in other equivalent Mesozoic assemblages around the Jurassic/Cretaceous boundary. Notably, crocodylomorphs shed teeth support a high morphological and ecological diversity of the group; while albanerpetontids remains are quite numerous and diverse in anatomical parts preserved. This allowed to erect the oldest albanerpetontid species from the Iberian Peninsula, and the first of Portugal. Together with another new species , the youngest of the Iberian Peninsula, the new Portuguese material allowed to review the phylogeny of Albanerpetontidae and propose a new hypothesis on their in-group relationship, as well as new insight on their palaeobiogeography at the end of the Cretaceous. |
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