DistributionRead full entry
Range DescriptionThis species occurs in southwestern Arizona (United States) and Sonora (Mexico) (McGuire 1996, Stebbins 2003). The range closely approaches that of Crotaphtyus bicinctores in a couple places along the Gila River, which separates the two species (McGuire 1996). In Arizona it is known from Gila, Mohawk, Little Ajo, Ajo, Pozo Redondo, Puerto Blanco, Sikort Chuapo, and Estrella mountains, as well as the Buckeye Hills, plus a few mountain ranges farther east, including the Quijotoa, Silverbell, and Tucson mountains, and probably also in the remaining mountain ranges south of the Gila River, though the Baboquivari Mountains might be inhabited by C. collaris (McGuire 1996). In Sonora it is known from: the transversely oriented foothills that follow the United States-Mexico border along Mexican Highway 2 (the Pinacate Region); several mountain ranges to the south and east in northern Sonora, including the Sierra Cubabi, Sierra La Gloria, Sierra El Alamo, and Sierra Rajon; either the Sierra Cubeta or Sierra El Pinto farther east in the northern foothills of the Sierra Madre Occidental (one specimen only); and north-south-trending valleys in Sierra Madre Occidental foothills east of Hermosillo and Guaymas (McGuire 1996). A distributional gap apparently exists between the Caborca region (Sierra El Rajon) and the Hermosillo-Guaymas region.