Amphibians and squamate reptiles from the latest Maastrichtian (Upper Cretaceous) of Blasi 2 (Huesca, Spain)

An assemblage of amphibians and squamates from the Upper Maastrichtian of the Iberian Peninsula is described here for the first time. The material is disarticulated and comes from the Blasi 2 site of Huesca, Spain). The site is made up of grey marls belonging to the lower part of the Tremp Formation, and contains dinosaurs, crocodilians, testudines and Osteichthyes. The amphibians from Blasi 2 include one albanerpetontid (Albanerpeton aff. nexuosum) and two different anuran taxa: a discoglossid and a palaeobatrachid. The squamates comprise three lizards (two indeterminate lizards and one anguid) as well as an indeterminate snake (Alethinophidia). The vertebrate assemblage may be interpreted as pertaining to an aquatic environment and its terrestrial surroundings. The presence of estuarine fishes, freshwater amphibians and marine invertebrates together suggests that Blasi 2 may correspond to a coastal, mangrove-like swamp. The amphibians and squamates of Blasi 2 are typically Laurasiatic taxa. This contrasts with the older (Campanian-Maastrichtian) sites of the Iberian Peninsula, where typical Gondwanan taxa have been identified. Blasi 2 provides important information on the biodiversity of amphibians and squamate reptiles in the north of the Iberian Peninsula during the late Maastrichtian, from a point just a few hundred thousand years before the K-T boundary event. These taxa have representatives in the Cenozoic, so as a group they do not appear to have been affected by the boundary event.