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Oms Oriol, Universitat Auṭnoma de Barcelona (Spain)
Violeta Riera, Universitat Auṭnoma de Barcelona (Spain)
Jaume Dinarès-Turell, Istituto Nazionale di Geofisica e Vulcanologia (Italy)
Angel Galobart, Institut Català de Paleontologia (Spain)
Rodrigo Gaete, Museu d'Isona i Conca dellà (Spain)
Rita Estrada, Universitat Auṭnoma de Barcelona (Spain)
Eudald Maestro, Universitat Auṭnoma de Barcelona (Spain)
Enric Vicens, Universitat Auṭnoma de Barcelona (Spain)
Bernat Vila, Institut Català de Paleontologia (Spain)
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European Maastrichtian dinosaur faunas are important to understand the last stages of dinosaur evolution before their extinction out of North America, where they have been studied more extensively. Localities such as the ones in the South-Pyrenean area provide long and well-dated sections with an outstanding record of dinosaur remains and other vertebrates, invertebrates, and plants. This record also contains the K/T boundary. Recent progress in the physical and time-correlation of different sections in the area are leading to a clear succession of events. The study of the site-forming processes and environments where dinosaur fossils are found, also contribute to detect the influence on the dinosaur succession. The over or under-representation of taxa in the succession (due to paleoenvironment and site forming processes) is also controlled after sedimentological studies.
In the Vallcebre syncline (South-Eastern Pyrenees) there is a succession of Maastrichtian strata up to 400 meters thick that belongs to the Tremp Formation. The age of the Vallcebre section is well constrained after the occurrence of a clear magnetostratigraphic succession that can be compared to the standard polarity scale after biochronological constraints. Dinosaur taxa include titanosaur sauropods, dromeaeosaurid theropods and hadrosaur ornithopods. The succession in the eastern part of the Tremp basin (South-Central Pyrenees) is 450 meters thick and belongs to the Arén and Tremp Formations. Dinosaur record consists of titanosaur sauropods, nodosaurid ankylosaurs, dromeaeosaurid theropods, basal hadrosauroid ornithopods, hadrosaurine ornithopods and lambeosaurine ornithopods.
On the whole, titanosaurid remains, although present throughout the series, mainly occur in the basalmost part in deposits of the Arén Fm and those of the grey unit of the Tremp Fm. Nodosaurid ankylosaurs are present only in the basalmost deposits of the series. Theropods are found all through the series. Basal hadrosauroid and hadrosaurine ornithopods occur throughout the series, although less frequently in the lower part. However, they are abundant in the mid and upper part. Regarding to lambeosaurine ornithopod remains, they are present in a particular moment close to the K-T boundary.
The whole record makes the South-Pyrenean area a remarkable succession to contribute to the understanding of the last European dinosaurs.
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