Contribution to knowledge of the last dinosaur footprints in Europe. Persistence of ornithopods in the upper Maastrichtian of SE Spain

Abstract

In the locality of Rambla de los Gavilanes (Betic Chain Murcia, Spain), six new outcrops with dinosaur footprints are reported from an uppermost Cretaceous succession of coastal marine deposits. Four of these sites are found in the upper part of the lower Maastrichtian and the other two in the upper Maastrichtian, these latter located only a few meters below the Cretaceous-Paleocene boundary (K/Pg). Traces appear as impressions or as natural casts, on tabular limestone beds consisting of micritic carbonate facies, these deposited in coastal marine areas that include a variety of environments (coastal lakes, tidal flats, salt marshes, and shallow coastal lakes). Two main types of traces have been recognized, respectively attributed to sauropod footprints and large ornithopod footprints with remarkable pointed hoof marks. The Maastrichtian sites with large ornithopod footprints in Europe are reported from Spain, Poland and Romania. Sauropod (titanosaurian), theropod (Irenesauripus and other undetermined theropods), and ornithopod footprints have been found at sites located up to 20 m below the K/Pg boundary. The Spanish dinosaur ichnites known closest to the K/Pg boundary are in the Pyrenean upper Maastrichtian, and are tridactyl, theropod and ornithopod (Hadrosauropodus and Amblydactylus) footprints. In this work, the assignation of the Rambla de los Gavilanes ornithopod footprints has been made following the recommended synthesis in several recent papers which reduce the large ornithopod ichnogenus to four.