:That's P. platyrhinos, the Desert Horned Lizard. Notice the two longer horns at the center of the back of the head, separated a bit from the horns on either side, the distinctive pattern of makings on the back, and the blunt rounded nose. Very pretty little lizard...very nice pic. Do you mind if download it? :
Thanks for the ID! Please feel free to download the image for educational, noncommercial purposes.