(Sphenodon punctatum), the sole surviving representative of the subclass Rhynchocephalia, known from the Triassic. Tuataras have biconcave vertebrae, two pairs of temporal fossae and two corresponding cranial arches, a quadrate bone immovably attached to the skull, a well-developed pineal body, and, as in fish, a sinus venosus in the heart. Externally, a tuatara resembles a lizard, with its massive body, large head, and penta-dactyl legs. On the back and tail is a low ridge of triangular scales. The body coloring is a dull olive-green.
Tuataras occupied both main islands of New Zealand prior to the arrival of the Europeans, but they were subsequently exterminated. They have survived only on rocky islets in the Bay of Plenty, where a special sanctuary was created for them. Tuataras live in holes approximately 1 m in depth, in which small petrels also frequently nest. They are active at twilight and at night. They feed on insects and other invertebrates and occasionally the eggs and nestlings of petrels. Mating takes place in January. From October to December, females lay eight to 15 hard-shelled eggs in the holes. Embryonic development lasts 12–15 months. Sexual maturity is not reached until age 20. Some tuataras have been known to survive as long as 50 years in captivity.
I. S. DAREVSKII