The tuatara Sphenodon punctatus is one of the real treasures of the zoology museum. Tuataras (from the Maori word for peaks on the back) are only found in New Zealand and are seriously endangered.
Tuatara Sphenodon punctatus
Photograph: Martyn L Gorman
Tuataras may be grey, olive, or brickish red in color. They range in adult length from about 40 cm (female) to 60 cm (large male), with the male generally reaching larger proportions. They lack external ears, have a diapsid skull (two openings on either side), and posses a "parietal eye" on the top of their head. This "third-eye," contains a retina and is functionally similar to a normal eye, though the function has not been clearly recognized and a scale grows over it in adult tuataras. The male tuatara displays a striking crest down the back of the neck, and another down the middle of the back. The female has a less developed version of this. Unlike all other living toothed reptiles, the tuatara's teeth are fused to the jaw bone (acrodont tooth structure). The tuatara has a very slow metabolism and is a very long-lived species. It's not uncommon for an individual to live for over 100 years.
Despite their appearance, tuataras are not lizards, they are the last remaining member of an ancient group of reptiles known as the Sphenodontia which was well represented by many species during the age of the dinosaurs, some 200 million years ago. All the species in the group, apart from the tuatara, declined and eventually became extinct about 60 million years ago.
Originally the tuatara was thought to be a lizard but in 1867, Dr Albert Gunther, the curator at the British Museum in London examined a bottled tuatara specimen and linked it to the land-based group of reptiles called Rhynchocephalia, a group thought to have been extinct for millions of years (Rhynchocephalia is now known as Sphenodontia). In 1989 Dr Charles Daugherty, of Victoria University in Wellington, discovered that there were two species of tuatara, Sphenodon punctatus and Sphenodon guntheri.
The two recognized species of tuatara are found on some 30 small, relatively inaccessible, islands off the coast of New Zealand. The species were once widely distributed throughout New Zealand, but became extinct on the mainland before the arrival of European settlers.
Our specimen probably dates from the early 1900s; is now Illegal to export tuataras from New Zealand. In 1895, New Zealand awarded the tuatara strict legal protection. It is currently considered a CITES (Convention on the International Trade in Endangered Species) Appendix I species. This is the most restricted classification for a species.