HIDDEN IN PLAIN SIGHT: REVISITING SOME KNOWN TETRAPOD TRACKWAYS OF THE WESCOGAME FORMATION (LATE PENNSYLVANIAN) OF GRAND CANYON NATIONAL PARK, ARIZONA, USA

Here, we examine three tetrapod trackways from the Wescogame Formation (late Pennsylvanian) of Grand Canyon National Park. These trackways have previously been documented, but have not yet been formally described. One of these trackways, which remains in situ near the South Kaibab Trail, was referenced and figured in Edwin McKee’s “The Supai Group of the Grand Canyon,” published in 1982. The other two trackways were collected in the 1930s and at one time were on public display within the park; both are currently housed in the park’s museum collections.

Our measurements and descriptions of these trackways are based on photogrammetric 3D models generated from photographs taken within the park and its facilities. In all three cases, the trackways appear to have been created by similar animals walking in eolian sand. Sedimentary features associated with the in situ trackway suggest that the environment was humid. We tentatively refer these trackways to the ichnogenus Amphisauropus, which has been attributed to seymouriamorph reptiliomorphs.