 Footprints belonging to the ichnogenus Brachychirotherium are often associated with aetosaurs . Brachychirotherium has been found from Rio Grande do Sul in Paleorrota , Brazil as well as Italy , Germany , and the eastern United States . They are also common in the southwestern United States , having been found from Canyonlands National Park and Dinosaur National Monument . Many of these tracks have a narrow gauge ( meaning left and right prints are placed closely together ) and nearly overstep each other . A 2011 functional analysis of the skeleton of Typothorax coccinarum indicated that it had the range of movement necessary to produce the tracks . 
