10 research outputs found
Shark fossil diversity (Squalomorphii, Squatinomorphii, and Galeomorphii) from the Langhian of Brielas (Lower Tagus Basin, Portugal)
The fossiliferous marine Miocene sediments of the Lower Tagus Basin (Portugal) present
a great diversity of Chondrichthyes forms. The current study focuses on the fossil
sharks from the Langhian Vc unit of the Brielas section, located in the Setúbal
Peninsula. A total of 384 isolated fossil teeth were analysed and ascribed to 17 species from the Orders Hexanchiformes, Squaliformes, Squatiniformes, Lamniformes,
and Carcharhiniformes. Centrophorus granulosus and Iago angustidens are described
for the first time in Portuguese sediments, whereas Pachyscyllium dachiardii and
Rhizoprionodon ficheuri represent only their second reported occurrence. Galeorhinus
goncalvesi was already known from the Portuguese uppermost Miocene (Alvalade
Basin), but it is now recognized in older sediments. Furthermore, the new material
seems to include the first reported occurrence of Hexanchus cf. agassizi in Miocene
sediments. As a whole, these new findings support the previous palaeoenvironment
characterization of a warm infralittoral setting gradually deepening to a circalittoral
one, where seasonal upwelling phenomena could have occurred