Skull of tuatara
The skull of the tuatara two openings a temporal fenestra on each side of the skull, with complete arches. In addition, the upper jaw is firmly attached to the skull. This makes for a very rigid, inflexible construction. The tip of the upper jaw is beak-like and separated from the remainder of the jaw by a notch. There is a single row of teeth in the lower jaw and a double row in the upper, with the bottom row fitting perfectly between the two upper rows when the mouth is closed. This specific tooth arrangement is not seen in any other reptile; although most snakes have a double row of teeth in their upper jaws, their arrangement and function is different from the tuatara’s. The jaws, joined by ligament, chew with backwards and forwards movements combined with a shearing up and down action.
About the animal
The name “tuatara” comes from the Maori for “peaks on the back.” Tuataras have spiny crests along their backs made from soft, triangular folds of skin. These spines are more prominent in males, who can raise them during territorial or courtship displays. The tuatara may look like a lizard, but it’s unique. The tuatara is not a lizard; it is the only living member of the order Rhynchocephalia, which flourished around 200 million years ago. All other members of the order became extinct 60 million years ago, in the late Cretaceous period. Mature tuataras usually measure between 12 and 30 inches long and weigh between 0.5 and two and a half pounds. Their skin is greenish gray and is sometimes speckled. Tuataras make their homes in coastal forest and low scrub, preferring areas with crumbly soil in which they can burrow.