Distribution of Phrynosoma ditmarsi Stejneger, 1906, with notes on habitat and morphology

The Rock Horned Lizard (Camaleón de Piedra, in Spanish), Phrynosoma ditmarsi, is a poorly known Mexican endemic species with a distribution restricted to the state of Sonora. The International Union for Conservation of Nature (IUCN) has categorized this species as Data Deficient (Frost et al., 2007), but using the Environmental Vulnerability measure (EVS) Wilson et al. (2013) assessed this species with a score of 16, placing it in the middle portion of the high vulnerability category; these authors regarded P. ditmarsi as highly vulnerable to environmental degradation because of its narrow geographic and ecological distribution. The Secretaría del Medio Ambiente y Recursos Naturales (SEMARNAT) listed this species as threatened (amenazada) in 2002, but in 2010 did not indicate a protected status (SEMARNAT, 2002, 2010).