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Sphenodontidae (tuatara; subclass Lepidosauria, order Rhynchocephalia) A monospecific family (Sphenodon punctatus, tuatara) of primitive, lizard-like reptiles up to 60 cm long, which have a horny, dorsal crest. The skull is of the primitive diapsid type, with a fixed quadrate bone. A pineal eye is present. The teeth are acrodont, with a tendency to develop a beak-like structure anteriorly. There is no copulatory organ. Tuataras are carnivorous, feeding on invertebrates and small vertebrates. They survive only on a few islands in the Bay of Plenty, New Zealand, and have protected status.

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