Nuevos datos sobre la fauna cenomaniense ibérica

Aunque el registro de vertebrados cenomanienses europeos era hasta ahora mal conocido, los hallazgos recientemente realizados en la región suroccidental de este continente permiten identificar una amplia diversidad, compuesta tanto por taxones de origen laurasiático como gondwánicos. Nuevos hallazgos realizados en la localidad portuguesa de Nazaré ayudan a profundizar en el conocimiento sobre estas faunas. Los resultados preliminares de su estudio han sido presentados en el 72 Annual Meeting de la Society of Vertebrate Paleontology (SVP), celebrado entre el 17 y 20 de Octubre en Raleigh (North Carolina, USA). Esta asociación faunística portuguesa se compone de taxones tanto marinos como continentales.
Se adjunta el citado resumen, correspondiente al trabajo “New data on the Cenomanian vertebrate site of Nazaré (West Central Portugal)”, cuya autoría corresponde a Callapez, P., Barroso-Barcenilla, F., Cambra-Moo, O., Pérez-García, A., y Torices, A.:
The Cenomanian vertebrate site of Nazaré is located in a coastal cliff of West Central Portugal with large exposures of Upper Cretaceous marginal-marine carbonates and continental siliciclastics. The study of this vertebrate site, internationally known by the presence of the unique dyrosaurid cited in Europe (attribution exclusively based on a mandibular symphysis), has been recently retaken after a detailed approach on its faunal assemblages and their biostratigraphic framework and paleoecologic significance. This new approximation reveals the presence of several valuable Lower and Middle Cenomanian fossiliferous levels, in which numerous vertebrate macroremains (shallow aquatic fauna; fishes, turtles and crocodilians) appear well preserved and partially articulated. Fish remains are abundant and mainly composed by scattered scales, teeth and skull fragments, though an almost complete specimen has been also found. Specifically, isolated teeth from Pycnodontiformes have been identified. They are crushing teeth with a smooth surface and subcircular or elongated crowns in oclussal view. They are very similar to the teeth belonging to the genus Coelodus. The other discovered teeth, isolated and included in fragments of dentary are elongated and inclined distally with the presence of a mesial flexure. They present a distal carina with a slightly wavy pattern and a better defined cutting edge in the mesial carina. Lingual longitudinal folds are present in the base of the crown. These teeth are remarkably similar to those classified as Enchodus. The specimen that is nearly complete presents primitive characteristics that allow us determining it as a primitive teleost cf. Elopomorpha. Turtle remains may correspond to Pan-Cryptodira and, probably, Pan-Pleurodira members. Both are likely aquatic forms, which may have lived in transitional or marine environments. New Crocodylomorpha material from this area has also been discovered, but it cannot be assigned to Dyrosauridae. All this material sheds new light on the little known record of European Cenomanian vertebrates. The particular location of Nazaré, close to the transition from Tethys to the Temperate domain, will be also useful to explain possible faunal changes and migrations influenced by sea-level changes and regional paleogeography.
Imagen: Angélica Torices posando alegremente junto al póster del citado trabajo.

No hay comentarios: