This iNaturalist photo was taken just north of the San Pedro River, which arises about 10 miles south of the international border in the Mexican state of Sonora. [There are no records of O. major in Sonora, but it is possible that the species occurs along that 10 miles of river.] From the international border, the San Pedro flows 150 miles north before joining the Gila River. Efforts to restore the natural flow of the San Pedro in Arizona should make it more likely that O. major will find suitable habitat along the length of the San Pedro.