sábado, março 28, 2015

Tartaruga Tropidemys em Portugal e pegadas de dinossauros em Cascais

Saíram recentemente dois artigos no Journal of Iberian Geology que tratam de vertebrados fósseis de Portugal: 1) a presença da tartaruga Tropidemys e 2) pegadas de dinossauros em Cascais

A. Pérez-García. 2015. Revision of the British record of Tropidemys (Testudines, Plesiochelyidae) and recognition of its presence in the Late Jurassic of Portugal. Journal of Iberian Geology.

The record of coastal marine turtles belonging to Plesiochelyidae is abundant in the Late Jurassic of Portugal. The material analyzed thus far has been attributed to two taxa: Plesiochelys and Craspedochelys. A specimen is presented here that allows extending the known diversity of Portuguese Jurassic turtles. It is attributed to Tropidemys. Although this taxon is relatively well known in the Kimmeridgian record of Switzerland and Germany, no specific allocation performed outside these countries can be, so far, confirmed. The detailed study of the poorly known British taxon “Pelobatochelys” blakii allows its specific validity to be confirmed here, being recognized as a member of Tropidemys. The revision of this species and the analysis of the new Portuguese specimen allow extending the knowledge regarding the genus Tropidemys.

V.F. Santos, P.M. Callapez, D. Castanera, F. Barroso-Barcenilla, N.P.C. Rodrigues, C.A. Cupeto
2015. Dinosaur tracks from the Early Cretaceous (Albian) of Parede (Cascais, Portugal): new contributions for the sauropod palaeobiology of the Iberian Peninsula. Journal of Iberian Geology.

A recently discovered Early Cretaceous (early late Albian) dinosaur tracksite at Parede beach (Cascais, Portugal) reveals evidence of dinoturbation and at least two sauropod trackways. One of these trackways can be classified as narrow-gauge, which represents unique evidence in the Albian of the Iberian Peninsula and provides for the improvement of knowledge of this kind of trackway and its probable trackmaker, in an age when the sauropod record is scarce. These dinosaur tracks are preserved on the upper surface of a marly limestone bed that belongs to the Galé Formation (Água Doce Member, middle to lower upper Albian). The study of thin-sections of the beds C22/24 and C26 in the Parede section has revealed a microfacies composed of foraminifers, radiolarians, ostracods, corals, bivalves, gastropods, and echinoids in a mainly wackestone texture with biomicritic matrix. These assemblages match with the lithofacies, marine molluscs, echinids, and ichnofossils sampled from the section and indicate a shallow marine, inner shelf palaeoenvironment with a shallowing-upward trend. The biofacies and the sequence analysis are compatible with the early late Albian age attributed to the tracksite. These tracks and the moderate dinoturbation index indicate sauropod activity in this palaeoenvironment. Titanosaurs can be dismissed as possible trackmakers on the basis of the narrow-gauge trackway, and probably by the kidney-shaped manus morphology and the pes-dominated configuration of the trackway. Narrow-gauge sauropod trackways have been positively associated with coastal palaeoenvironments, and the Parede tracksite supports this interpretation. In addition, this tracksite adds new data about the presence of sauropod pes-dominated trackways in cohesive substrates. As the Portuguese Cretaceous sauropod osteological remains are very scarce, the Parede tracksite yields new and relevant evidence of these dinosaurs. Furthermore, the Parede tracksite is the youngest evidence of sauropods in the Portuguese record and some of the rare evidence of sauropods in Europe during the Albian. This discovery enhances the palaeobiological data for the Early Cretaceous Sauropoda of the Iberian Peninsula, where the osteological remains of these dinosaurs are relatively scarce in this region of southwestern Europe. Therefore, this occurrence is also of overall interest due to its impact on Cretaceous Sauropoda palaeobiogeography

Sem comentários: