Tuatara (Sphenodontidae Family)
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An amazing throw-back to another time, the Tuatara (Maori for "old spiny back") is the last surving member of the Rhynchocephalia Order, more commonly renamed Order Sphenodontia after its only remaining species.
Some 225 million years ago, during the Triassic Period, the Lepidosaurs of the day divided into the Order Squamata (Snakes and Lizards) and Sphendodont (Tuatara). The Tuatara has barely evolved over this amazing period of time and is a rare showcase of life as it was in the Triassic.
Lizard like, but predating both modern day lizards and snakes, the Tuatara has no remaining close relatives, with other Sphendodont species becoming extinct some 60 million years ago.
The Tuatara has survived as a result of geographic isolation. Tectonic plate movements separated New Zealand from Australia some 90 million years ago before terrestrial mammals and other potential predators were able to cross the Tasman Sea. In more recent times, humans arrived with dogs, cats and other animals, eventually reducing Tuatara populations to around 30 predator free islands.
Tuatara are an amazing and highly unusual animal. Running on what seems like a different time clock, eggs take over 12 months to hatch, hatchlings take over 13 years to mature sexually and over 30 years to reach full length. The Tuatara reproduces only every 3 or 4 years and may live to over 100 years of age.
Teeth are solid projections of jawbone, one row on the lower jaw that fits between two rows on the upper jaw. Gender is determined by the incubation temperature of eggs and unlike most reptiles, the Tuatara is more comfortable in cool weather, surviving sub-zero temperatures.
Like some other reptiles, the Tuatara has a third-eye (Pineal Eye) that is light sensitive and seems to assist with regulating time in the sun and direction.
The Tuatara may not be as physically impressive as the Komodo Dragon, however its evolutionary stability and survival for hundreds of millions of years makes the Tuatara a very interesting animal for scientific study.
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TUATARA
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|  | Sphenodon punctatus
| The Cook Strait Tuatara is the most common of the two Tuatara species, with around 50,000 of them living on Stephen's Island in the Marlborough Sound near mainland New Zealand.
The male Tuatara grows to around 60cm (24in) in length and weighs around 1kg. The female is slightly shorter and around half the mass of the male. The Tuatara has a crest of spines along its back, a little less prominent on the female.
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Image: David Warwick (Taronga Zoo Exhibit - Jan 2005)
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