A Wet Interdune Dinosaur Trampled Surface in the Jurassic Navajo Sandstone, Coyote Buttes, Arizona: Rare Preservation of Multiple Track Types and Tail Traces

Abstract

Abstract A distinctive, disturbed surface with numerous soft-sediment impressions occurs within a wet interdune interval of Jurassic Navajo Sandstone at the Coyote Buttes along the Arizona-Utah border. These high-density impressions are interpreted as footprints that comprise a dinosaur trampled surface. This surface displays an unusual combination of multiple overlapping track types and sizes, distinct to modified footprint features that include claws and toes and rare tail traces. The trampled surface covers ∼3000 m2 with an average density of ∼12 impressions/m2 in its main extent. Although modern water collection and biofilms typical of weathering potholes or pits are superimposed on this surface, the primary origin of the impression features are trace fossil structures formed prior to lithification. Four criteria distinguish the impressions as vertebrate in origin: (1) large—up to several tens of centimeters—repeating identifiable foot morphologies; (2) impression floors surrounded by soft-sediment ma...