A review of dinosaur track occurrences from the Morrison Formation in the type area around Dinosaur Ridge

Abstract

Abstract Although the type section of the Morrison Formation, near Denver Colorado, now also well-known as Dinosaur Ridge, has since 1877 been world famous as the source of iconic Late Jurassic dinosaurs like Stegosaurus , Apatosaurus , and Diplodocus , little detailed information has been published on fossil footprints from the formation in this area. Late Jurassic (Morrison) footprints were not reported from the type section at Dinosaur Ridge until the early 1990s. Since then, other footprints have been reported, and their precise stratigraphic occurrences documented. To date, diagnostic examples of theropod, sauropod, and thyreophoran (stegosaur) tracks have been documented from at least three different locations. The quality of preservation of these tracks ranges from moderately good to quite poor. Nevertheless, more than 25 individual footprints, including some undertracks, have been identified unequivocally, including several manus–pes sets of quadrupedal trackmakers. The track assemblages are typical of many small Morrison Formation ichnofaunas and are consistent with what is known of the body fossil assemblages. The track assemblage is reviewed and compared with summary data from the 64 Morrison Formation tracksites currently known.