Dinosaurios terópodos del Jurásico Superior de Portugal en las VIII Jornadas de Salas de los Infantes

Los dinosaurios terópodos del Jurásico Superior de Portugal han sido los protagonistas de una de las ponencias en las pasadas VIII Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno. Este trabajo ha resultado de proyectos de investigación que el Grupo de Biología Evolutiva de la UNED ha desarrollado en los últimos años sobre el registro de vertebrados mesozoicos de la Cuenca Lusitánica. En el congreso, se presentó un resumen sobre la diversidad y distribución de terópodos en los niveles del Jurásico Superior portugués y se ha discutido la importancia del registro de la Cuenca Lusitánica para el conocimiento de la historia evolutiva de estos dinosaurios, así como sus implicaciones paleoambientales y paleobiogeográficas.

El resumen es el siguiente:

The Upper Jurassic levels from Portugal have yielded the most significant record of dinosaurs for this age in Europe and one of the most abundant worldwide. These levels correspond to filling deposits of the Lusitanian Basin, a tectonosedimentary structure which origin is related to the opening of the north sector of the Atlantic Ocean. The central sector of the Lusitanian Basin corresponds mainly to distal fluvio-deltaic or coastal environments and produced the richest fossil record of Mesozoic terrestrial vertebrates in Portugal. This sector has been divided into four Upper Jurassic sub-basins (Consolação, Turcifal, Arruda, and Alcobaça-Bombarral), which might represent diverse contemporaneous communities, occupying different palaeoenvironments, more or less open to coastal influences. The distribution of theropod remains between the different sub-basins of the Lusitanian Basin is very unequal, probably biased by the fact that the best prospecting conditions occur in coastal areas.

Theropod remains are relatively abundant in Upper Jurassic levels of the Lusitanian Basin and include mainly medium to large-sized forms with a transatlantic distribution. The faunal composition of theropods from the Morrison Formation and the Lusitanian Basin is much similar with most of the genera currently known in the Portuguese record having a closely related taxon at the North American record. However, the Portuguese record also includes some exclusive taxa (Lourinhanosaurus) and clades up to now unknown in North American Jurassic (Carcharodontosauria). This combination of shared and endemic taxa is compatible with an incipient vicariant evolution related with the first stages of the north Atlantic opening. The development of dispersal routes between Europe and North America after the late Tithonian could explain the presence of carcharodontosaurians during the Early and Late Cretaceous of North America. A land reconnection between Europe and North America due to a dramatic drop in sea level during the mid-Valanginian was previously proposed to explain the palaeobiogeographic context of other dinosaur groups such as the turiasaurian sauropods.

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Más información:

• Referencia: Malafaia, E., Mocho, P., Escaso, F., Ortega, F. 2019. The fossil record of theropod dinosaurs from the Portuguese Upper Jurassic: ecological and biogeographical implications. Libro de resúmenes de las VIII Jornadas Internacionales sobre Paleontología de Dinosaurios y su Entorno: 21-24.
• Imágenes: Elisabete Malafaia durante la presentación.