Early Permian vertebrate assemblage and its biostratigraphic significance, Arroyo del Agua, Rio Arriba County, New Mexico

Abstract

Early Permian vertebrate fossils from the upper part of the El Cobre Canyon Formation of the Cutler Group in the area around Arroyo del Agua, Rio Arriba County, New Mexico, encompass an extensive assemblage of chondrichthyans, osteichthyans, temnospondyls, microsaurs, a seymouriamorph, diadectomorphs, a parareptile, captorhinomorphs, an araeoscelid, and basal or pelycosaurian-grade synapsids. This long and extensively collected and studied vertebrate assemblage comes from a narrow stratigraphic interval about 50-60 m thick, and we treat it as a single biostratigraphic assemblage. The presence of Zatrachys, Bolosaurus and Chenoprosopus indicates correlation of this assemblage to the Bowie Group in Texas, and thus suggests an age for the upper El Cobre Canyon Formation of early Wolfcampian.