A taxonomic revision of South American Stenocercus (Squamata: Iguania) lizards

South American Stenocercus lizards occur mostly in the Andes and adjacent lowland areas from northern Colombia and Venezuela to central Argentina at elevations of 0-4000 m. In this paper, 61 species of Stenocercus are recognized, including one resurrected as S. angulifer. Morphologically, S. angulifer more closely resembles S. aculeatus. For each species, a diagnosis, description, and summary of distribution are provided based on examination of 2001 specimens and data from the literature. Notes on color in life and natural history are included for most species. Additionally, a dichotomous key to assist in the identification of specimens is provided.