Sphenodon is a type of reptile that is commonly known as the tuatara. Tuatara belongs to the order Rhynchocephalia, which is an ancient group of reptiles that have existed for over 200 million years. Synonyms for sphenodon include tuatara and Sphenodon punctatus which are the two species of tuatara. Tuatara are found in only a few locations in New Zealand and are considered a national icon of the country. They have a unique appearance with a spiny crest on their back and a third eye on the top of their head. Tuatara are not lizards, and they have unique features like beak-like teeth and highly developed hearing.