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2023 |
Considerations on the Portuguese Sirenia (Mammalia) fossil record.
Journal of Iberian Geology https://doi.org/10.1007/s41513-023-00214-w 5 tabs. 7 figs. Aug. 16, 2023.
–ABSTRACT: Marine mammals of the Order Sirenia are good palaeoenvironmental proxies in paleontological studies, due to their specific feeding and habitat adaptations. Fossils of sirenians are rather common in the Portuguese Neogene, having been reported for nearly 100 years, although most findings correspond to rather fragmentary material, with no diagnostic value. Still, some nominal taxa of Sirenia were referred to in the literature, based either on identifiable fossils or on some undescribed material preserved in collections. Following revisions of published occurrences and new descriptions of previously unpublished material, a general review of the fossil sirenians of Portugal is presented, covering both the main geographic areas and the nominal taxa referred to in the literature. Several findings are corrected regarding the taxonomic classification, clearing the fossil record of Portugal, and making available for researchers the complete list of Sirenia findings and their geolocation in the Portuguese Neogene. An analysis of the Portuguese Sirenia fossil record allowed to solve problems associated to the previous published taxonomic works and increase the knowledge regarding the Lower Tagus Basin, Setubal Peninsula, Alvalade Basin and Sirenia evolution in Portugal during the Lower and Middle Miocene. The Portuguese fossil record of sirenians shows evidence that these marine mammals were migrating towards the south, which agrees with the European data, strengthening the present interpretation that sirenians took refuge in the Mediterranean and Gulf of Cadiz by the end of the Miocene, inhabiting these regions up to the beginning of the Northern Hemisphere Continental Glaciations by the end of the Piacenzian.
RESUMEN: Los mam?feros marinos del Orden Sirenia son buenos proxies paleoambientales en estudios paleontol?gicos, debido a sus adaptaciones espec?ficas de habitat y alimentaci?n. Los f?siles de sirenios son bastante comunes en el Ne?geno portugu?s, habiendo sido citados desde hace casi 100 a?os, aunque la mayor?a de los hallazgos corresponden a material bastante fragmentario, sin valor diagn?stico. A?n as?, algunos taxones nominales de Sirenia fueron referidos en la literatura, basados en f?siles identificables o en alg?n material no descrito conservado en colecciones. Despu?s de las revisiones de las ocurrencias publicadas y de las nuevas descripciones de material in?dito, se presenta una revisi?n general de los sirenios f?siles de Portugal, cubriendo tanto las principales ?reas geogr?ficas como los taxones nominales referidos en la literatura. Se corrigen varios hallazgos relativos a la clasificaci?n taxon?mica, despejando el registro f?sil de Portugal, y poniendo a disposici?n de los investigadores la lista completa de hallazgos de Sirenia y su geolocalizaci?n en el Ne?geno portugu?s. El an?lisis del registro f?sil portugu?s de Sirenia permiti? resolver problemas asociados a los trabajos taxon?micos publicados anteriormente y aumentar el conocimiento sobre la cuenca inferior del Tajo, la pen?nsula de Set?bal, la cuenca de Alvalade y la evoluci?n de Sirenia en Portugal durante el Mioceno inferior y medio. El registro f?sil portugu?s de sirenios muestra evidencias de que estos mam?feros marinos migraban hacia el sur, lo que concuerda con los datos europeos, reforzando la presente interpretaci?n de que los sirenios se refugiaron en el Mediterr?neo y Golfo de C?diz a finales del Mioceno, habitando estas regiones hasta el inicio de las Glaciaciones Continentales del Hemisferio Norte a finales del Piacenziano.
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