Representatives of several families are limbless and resemblesnakes, whereas others have long hind legs that permit bipedallocomotion. Male lizards may be outfitted with a wide array of ornamentation—such as extensible throat fans and frills, throat spines, horns or casques on the head, and tail...
Male tuatara have no paired copulatory organ; they have saclike structures from which the paired hemipenes of squamates were likely derived. In addition, the tuatara does not have a movable quadrate bone in the jaw; this characteristic is present in all squamates. Watch: A chameleon's ...