This is a beautiful photo! I know that the Denver Zoo has Dwarf Shield-tailed Agamas (Xenagama taylori) in their collection, but I think this photo might be one of their Uromastyx lizards, which is a closely related and similar-looking group. Shield-tailed Agamas usually have a dorsal pattern with finer speckling than this and their forelegs and cheeks are not usually this robust. Thank you for posting this photo.
