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 bed ding plane is exposed and exhibits thousands of ovate prints that had been interpreted as dinosaur tracks. Detailed study of these trace fossils allow s the proposal of an alternative hypothesis that they were produced by the feeding activity of rays or other fish with similar behavior Comparison wit h modern stingray pits from a tidal flat in Puerto Penasco, Sonora, Mexico, reveals a great deal of similarity with the Cretaceous trace fossils in th eir distribution, morphology, environmental setting, and associated inverte brate bioturbation. Moreover, ray body fossils are known from neighboring c ontemporaneous deposits. The trace fossils here are attributed to the ichno genus Piscichnnus.