Cover Image Credits: (Top) Revised Triassic chronostratigraphy of the Colorado Plateau of Southwest United States and its earliest documented dinosaur record, as compared to that of the Ischigualasto-Villa Unión Basin of northwestern Argentina (this issue, p. 981–1008, fig. 7). High-precision U-Pb geochronology sheds new light at North America's earliest dinosauromorph assemblages and raises questions about the existing diachronous model for the transcontinental radiation of early dinosaurs. U-Pb analyses of volcanic zircon (bottom left) constrain the age (bottom center) of the renowned Placerias Quarry fauna in eastern Arizona and their context within the stratigraphy of the Upper Triassic Chinle Formation (bottom right).