Vertebrate fauna at the Allosaurus fossil-site of Andrés (Upper Jurassic), Pombal, Portugal
- E. Malafaia
- F. Ortega
- F. Escaso
- P. Dantas
- N. Pimentel
- J. M. Gasulla
- B. Ribeiro
- F. Barriga
- J. L. Sanz
ISSN: 1886-7995, 1698-6180
Any de publicació: 2010
Títol de l'exemplar: Mesozoic Terrestrial Ecosystems and Biota
Volum: 36
Número: 2
Pàgines: 193-204
Tipus: Article
Altres publicacions en: Journal of iberian geology: an international publication of earth sciences
Resum
An overview of the faunistic diversity of the Andrés fossil-site from the Portuguese Upper Jurassic is presented. This work provides a preliminary approach on the vertebrate fauna known at present. Although this quarry is known since the 1990's, due to the description of the firts robust evidence of a member of the neotetanuran genus "Allosaurus" outside North America, the results presented here are mainly derived from the analysis of the elements found during the second and third field season in 2005. At the moment, among the material collected from Andrés it was identified remains that represent a diverse vertebrate fauna including fishes, sphenodonts, crocodylomorphs, pterosaurs, and at least seven distinct dinosaur forms. The recovery of this diverse and abundant osteological collection from one unique fossil-site is noteworthy for the Upper Jurassic Portuguese record, and only comparable with those from the Guimarota coalmine. Due to these two features plus the good preservation of the fossils, the Andrés quarry may be a site of reference for the analysis of vertebrate ecosystems from the Portuguese Upper Jurassic. Dinosaur elements are the most abundant fossils, and among them it is particulary common the presence of remains identifield as "Allosaurus". These new evidences allow testing the previous phylogenetical hypothesis ascribing the first theropod remains from Andrés to "A. fragilis", a species described in synchronic levels of the North American Morrison Formation. The similarity between the Allosaurus remains collected in Andrés and some specimens from the Morrison Formation seems to point the existence of a genetic flow between some continental vertebrates on both sides of the proto-north Atlantic during the Upper Jurassic. Favourable tectonic conditions for the occurrence of punctual contacts between the two continents is, at present, the best scenario for explain this situation.