Tuatara
The tuatara is the only surviving member of the order Rhynchocephalia. It is native to a small number of islands off New Zealand and has been classified as an endangered species since 1895. Tuatara, like many native New Zealand species, is threatened by habitat loss, harvesting, and introduced species such as mustelids and rats.
There are two extant subspecies: Sphenodon punctatus and the much rarer Sphenodon guntheri.
Though it resembles a lizard, it has several characteristics unique among reptiles. Its teeth are fused to its jaw bone; it has no external copulatory organs or earholes. Indeed, tuatara were originally classified as lizards in 1831 when the British Museum received a skull. The species remained misclassified until 1867, when Gunther (also at the British Museum) noted certain bird-like, turtle-like, and crocodile-like features and proposed the order Rhynchocephalia for the tuatara and its fossile relatives.
The name tuatara derives from the Māori language, meaning "spiny back". Tuatara feature in a number of indiginous legends; they are ariki (God forms). Tuatara are regarded as the messenger of Whiro, the god of death and disaster. Māori women are forbidden to eat tuatara.
It thrives in much lower temperatures than are tolerated by most reptiles, preferring temperatures of 60 to 70 degrees Fahrenheit (16-21 C); temperatures over 80 (27) degrees are fatal. Adults are about 50cm long and weigh maybe three kilograms. Tuatara are notoriously cryptic, and hibernate in winter. Adults are terrestrial and nocturnal; hatchlings are arboreal and diurnal.
It is extremely long-lived, with individuals commonly living for over a century, and reproduces very slowly: tuataras take at least ten years to reach sexual maturity, females only lay eggs once every four years, and it takes between 12 and 15 months after copulation for a new tuatara to hatch from its egg. Like some lizards, it has a third eye on the top of its head; in adult animals a scale grows over the eye, and its purpose isn't clear.
