The flat-tail horned lizard (Phrynosoma mcallii ) is a species of lizard in the family Phrynosomatidae. A species of reptile, it is endemic to the Sonoran desert of the southwestern United States and northwestern Mexico. Its multiple adaptations for camouflage help to minimize its shadow. The species is threatened, with a restricted range under pressure from human activities such as agriculture and development, and is specially protected in the United States.
