First finding of dinosaur eggs (Upper Cretaceous) in the La Rioja province, Argentina.

Numerous sites containing dinosaur eggshells have been found in the Los Llanos Formation in the Sanagasta Valle, La Rioja Province, Argentina. The eggs were classified as Sphaerovum erbeni Mones, corresponding to dinosaurs with a basic type of Dinosauroid-spherulite organization and a filisferulitic morphotype, belonging to the Faveoloolithidae Oofamily, similar to others reported previously in Uruguay and in the Rio Negro and La Pampa provinces, Argentina. The fossils were found in situ, although fragmented mainly due to the process of paedogenesis. The studied eggshells indicate a Campanian-Maastrichtian age, being the first fossils of the age in the Sierra de Velasco region.