Sceloporus merriami annulatus, commonly known as the Big Bend canyon lizard, is a subspecies of the canyon lizard, and is endemic to southwestern Texas and adjacent northeastern Mexico.

[1] The subspecific name, annulatus, comes from the Latin noun annulus, meaning "ring", and refers to the banded subcaudal surface.

[1] S. m. annulatus is native to a fairly narrow range from the Big Bend region of the US state of Texas, to eastern Coahuila in Mexico.

It has a fairly large head for its body size, and a dewlap which is larger in males than females.

Their primary choice of habitat is rocky, unvegetated canyon lands with numerous crevices to hide in, and ledges to bask on.