Cretaceous ray traces?:: An alternative interpretation for the alleged dinosaur tracks of La Posa, Isona, NE Spain

At the locality of La Posa, Isona, Spain, an extensive Upper Cretaceous bedding plane is exposed and exhibits thousands of ovate prints that had been interpreted as dinosaur tracks. Detailed study of these trace fossils allows the proposal of an alternative hypothesis that they were produced by the feeding activity of rays or other fish with similar behavior Comparison with modern stingray pits from a tidal flat in Puerto Penasco, Sonora, Mexico, reveals a great deal of similarity with the Cretaceous trace fossils in their distribution, morphology, environmental setting, and associated invertebrate bioturbation. Moreover, ray body fossils are known from neighboring contemporaneous deposits. The trace fossils here are attributed to the ichnogenus Piscichnnus.