tuatara in natural environment (IMAGE) Iowa State University Caption The tuatara, whose ancestors once roamed the Earth with dinosaurs, is the last living species of the order Rhynchocephalia, a key link between ancient reptilian species and modern reptiles, birds and mammals. A new study explores the gnome of the tuatara. Credit Nicola Nelson Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.