New dinosaur footprints from the ‘mid’-Cretaceous (Albian-Cenomanian) series of the Ouled Nail Mounts (Algeria)

Eight newly-discovered dinosaur tracks in the Ouled Nail Mounts are referred to small-sized theropods and ornithopods, respectively. Based on new ammonite findings, the track-bearing succession can be dated as Late Albian–Early Cenomanian. The tracksite occurs in a dolostone layer with pes tracks preserved as concave epireliefs, associated with the invertebrate traces such as Skolithos isp. and Thalassinoides isp. as well as gastropod and bivalve shells indicating an intertidal environment with periodic storm-generated deposits. Two morphotypes are identified, here designated as MT1 and MT2, MT1 is a typical grallatorid form and can be attributed to small theropods, whereas MT2 attributed to small ornithopods. Along with footprint assemblages from Amoura and Daiet El Arbi as well as known dinosaur body fossils from Djoua, Béchar, Oued Boudjihane and Gara Samani, these new discoveries are evidence of the stratigraphically youngest occurrences of dinosaurs in Algeria. Furthermore, the ornithopod footprints represent the first ornithischian record in this country.