Originally it was thought that there was only one species of tuatara, Sphenodon punctatus. That is until recently when genetic research showed that there is actually two different species both S.punctatus and S.guntherii.Tuataras only live on the islands of New Zealand. Although they might superficially resemble lizards, tuataras are not in any lizard family. Some of the things that makes tuataras different from lizards are a lack of external ears, a more formed parietal eye and a lack of hemipenes or even a penis in general.
There are some things that tuataras share in common with lizards. The biggest one is caudal autotomy. That is the animals are able to drop their tales when danger threatens.The two species of tuatara are listed below. Just click on the one you want to learn more about.