The oldest record of drepanosaurids (Reptilia Diapsida) from the Placerias quarry, Arizona, USA, and the stratigraphic range of the Drepanosauridae

Previous detailed descriptions of relatively complete drepanosaurid material make it possible to recognize isolated drepanosaurid elements from other localities. The identification of isolated elements from the USA and Great Britain extended the geographical distribution Of the group and encouraged a review of Triassic collections for characteristic elements of this family. in this paper, isolated vertebrae previously described as problematic reptiles from the famous Placerias Quarry, near St. Johns, Arizona, USA are re-identified as drepanosaurids. These specimens represent the oldest occurrence of this family, which is carliest Adamanian.