First record of a dinosaur for the Oriente Basin at the Tena Formation (Upper Cretaceous) of Ecuador

New sauropod materials from Ecuador were found in rocks of the upper part of the Tena Formation (Maastrichtian, Upper Cretaceous) at the Napo River area. They consist of an associated forelimb including a partial humerus and five partial metacarpals. The specimen differs from the previous saltasaurine titanosaur finding in Loja for being larger and more slender, in a way that might be consistent with those of colossosaurian titanosaurs. The Tena Formation was deposited in a lagoon-like transitional environment with marine incursions, consistent with regional geological evolution models in the context of the Andean uplift. This discovery expands our knowledge of sauropod diversity in the Late Cretaceous of northern South America and corroborates a wider distribution of titanosaurs in the region. Since the material was first found and excavated by non-trained people part of the bones were lost, preserving only some bones and early photos.