Dinosaur natural track casts from the Lower Cretaceous Hekou Group track formation, and distr

anthropo itten/He track casts are deep natural tracks left in soft and moist substrates with a relatively high cohesiveness. ackmakers and their tracks preserved as w tracksites suggest cksite. However, it is ple area and the fact all tracks and more w sites suggest that is much wider than red within the basin. All rights reserved. Dinosaur tracks can be preserved in various forms, including molds (impressions, true tracks, undertracks, overtracks), casts, and casts of deep tracks (three-dimensional tracks, preserved in convex hyporelief). The term “four-dimensional tracks ” has recently been proposed for 3D tracks that show traces of movement, such as ss). Many dinosaur tracks are preserved as molds (convex epireliefs) exposed in plain view on bedding planes (Lockley, 1997). Casts of deep tracks, on the other hand, appear as rounded bulges protruding from the bases of sandstone beds into the underlying sediment layer (such as deformed sandstone beds, “Brontosaur Bulges”, Lockley, 2001; Lockley and Marshall, 2014). Some casts are well preserved and can easily be assigned to distinct track morphotypes. Meanwhile, such casts of deep tracks have been described for all major dinosaur groups including ornithopods (Difley and Ekdale, 2002; Currie * Corresponding author. Contents lists availa