The tetrapod fauna of the Upper Triassic lower Chinle Group (Adamanian:latest Carnian), of the Zuni Mountains, west-central New Mexico

Numerous localities in the Bluewater Creek Formation in the Zuni Mountains of westcentral New Mexico produce a tetrapod fauna that includes the metoposaurid amphibian Buettnena sp., indeterminate phytosaurs, the aetosaurs Stagonolepis, Desmatosuchus, and Paratypothorax, two theropod dinosaurs, at least two ornithischian dinosaurs, including one identified here as aff. Tecovasaunls, and trace fossils consisting of a footprint of an ?ornithischian, and vertebrate coprolites. The most frequently encountered fossils are abundant cranial and postcranial fragments of metoposaurid amphibians and indeterminate phytosaurs. Stagonolepis is an index taxon of the Adamanian land-vertebrate faunachron, indicating that the Bluewater Creek Formation is latest Carnian in age, an observation consistent with abundant Desmatosuchus and large metoposaurid amphibians. The overlying Blue Mesa Member of the Petrified Forest Formation is relatively unfossiliferous in the Zuni Mountains, and has only produced fragmentary remains of indeterminate metoposaurs and phytosaurs, but produces an Adamanian fauna from various localities in Arizona. The dinosaur fauna from the Bluewater Creek Formation comes from a single locality, is the most diverse late Carnian dinosaur assemblage in North America, and includes some of the oldest known dinosaurs.