T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Tuatara (Sphenodon punctatus) Cook Strait tuatara.

Kingdom: Animalia
Phylum: Chordata
Order: Rhynchocephalia
Family: Sphenodontidae
Subfamily: Sphenodontinae
Genus: Sphenodon
Species: Sphenodon punctatus
Common name: Cook Strait Tuatara.

The tuatara is a reptile that is endemic to New Zealand which, though it resembles most lizards, is part of a distinct lineage, order Rhynchocephalia.
There are three different species of Tuatara in New Zealand:
- Northern Tuatara (Sphenodon Punctatus Punctatus) a
sub-species which live on offshore islands around the north of the North Island.
- Cook Strait Tuatara (Sphenodon Punctatus)
- Brothers Island Tuatara (Sphenodon Guntheri)

Sphenodon punctatus is a tuatara that lives on
Stephen's Island and the Trios group (3 Islands) in the Marlborough Sounds area.
Tuataras are the only surviving members of its order, which flourished around 200 million years ago. Their most recent common ancestor with any other extant group is with the squamates (lizards and snakes). For this reason, tuataras are of great interest in the study of the evolution of lizards and snakes, and for the reconstruction of the appearance and habits of the earliest diapsids (the group that also includes birds, dinosaurs, and crocodiles).
Tuatara are greenish brown and grey, and measure up to 80 cm from head to tail-tip and weigh up to 1.3 kg with a spiny crest along the back, especially pronounced in males. Their dentition, in which two rows of teeth in the upper jaw overlap one row on the lower jaw, is unique among living species. They are further unusual in having a pronounced photoreceptive eye dubbed the "third eye", whose current function is a subject of ongoing research but is thought to be involved in setting circadian and seasonal cycles. They are able to hear, although no external ear is present, and have a number of unique features in their skeleton, some of them apparently evolutionarily retained from fish. Although tuataras are sometimes called "living fossils", recent anatomical work has shown they have changed significantly since the Mesozoic era.
The name "tuatara" derives from the Māori language, and means "peaks on the back”. The tuataras have been protected by law since Tuatara, like many of New Zealand’s native animals were threatened by habitat loss and introduced predators, such as the Polynesian rat (Rattus exulans). They were extinct on the mainland, with the remaining populations confined to 32 offshore islands, until the first mainland release into the heavily fenced and monitored Karori Sanctuary in 2005. During routine maintenance work at Karori Sanctuary in late 2008, a tuatara nest was uncovered, with a hatchling found the following autumn. This is thought to be the first case of tuatara successfully breeding on the New Zealand mainland in over 200 years, outside of captive rearing facilities.

A tuatara egg hatching with two other new hatched lizards... Photographed at Zealandia, Wellington.

A large tuatara photographed at Zealandia, Wellington.

A young tuatara at Karori "Zealandia" sanctuary, Wellington.

A tagged male tuatara at Karori "Zealandia" sanctuary, Wellington. 

A tuatara skull.

Thanks to Wikipedia for text and information http://creativecommons.org/licenses/by-sa/3.0/