Tuatara
. Tuatara, common name for two species of lizardlike reptiles, the only surviving species of an order that flourished about 200 million years ago during the Jurassic period. Tuataras are found only on about 30 islands off the coast of New Zealand. Stocky and big-headed with a strong tail and a spiny crest down the back, they differ from lizards in having a complete lower temporal arch on the skull behind the eye. Tuataras may grow to a length of about 60 cm (about 24 in), usually taking 20 years to reach maturity. They are solitary, burrowing reptiles, feeding mostly at night on insects, lizards, snails, and bird chicks and eggs. Scientific classification: Tuataras make up the genus Sphenodon of the family Sphenodontidae, order Rhynchocephalia. They are classified as Sphenodon punctatus and Sphenodon guntheri.