THE GATEWAY LOCALITIES OF MESA COUNTY, COLORADO AND THE CONTINUING EARLY MESOZOIC FOSSIL FOOTPRINT BONANZA

Dinosaur tracks were first reported from the Late Triassic, Chinle Group of the Gateway area in the early 1980s. Since this time the area has become an unprecedented source of diverse and well-preserved fossil footprints from both the Chinle Group and overlying Wingate Formation which is in part Early Jurassic .

Tracks from the Chinle Group (with probable trackmakers) Brachychirotherium (aetosaur), Grallator (theropod), Tetrasauropus (?sauropod), Pseudotetrasauropus (?prosauropod), Rhynchosauroides (lepidosaurs) possible synapisd and/or mammal tracks.

Tracks from the Wingate Formation (with probable trackmakers) include Batrachopus (crocodilian), Brasilichnium (synapsid), Grallator and ?Eubrontes (theropod) and Otozoum (prosauropod).

The most significant new discoveries from the gateway area include five parallel trackways of Otozoum from the Wingate. These represent the first report of this ichnogenus from the Wingate, the oldest report of Otozoum in the western USA and the best evidence that the trackmaker was gregarious.

Similarly, a recent discovery of a site with a very high density of Batrachopus tracks, is also the first substantial report of these tracks from the Wingate. Batrachopus has rarely been found abundantly in the Western USA, except at the St George site (Moenave Formation, SW Utah). Thus, the Gateway site is an important addition to the ichnological record of the Wingate.