brother's island tuatara

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The tuatara is genus of reptiles found only in New Zealand. The genus contains only two living species - the Brothers Island tuatara (Sphenodon guntheri) and the Northern tuatara (Sphenodon punctatus). When the tuatara was first scientifically classified in 1831 they were assumed to be lizards. In 1867 the order Rhynchocephalia (meaning “beak head”, in reference to the distinctive skull structure) was created by Albert Günther of the British Museum, for the tuatara and its fossil relatives.

The tuatara is often referred to as a living fossil due to several primitive features that they still have, though they have changed significantly since the  Mesozoic era.

The brain structure and manner in which tuatara move is more similar of amphibians than reptiles, whilst their heart has the most primitive structure of any reptile and their lungs have only a single chamber and lack bronchi.

The skulls of tuataras also shows their age - it is simple in build with two openings (temporal fenestra) on each side of the skull, with complete arches, and the upper jaw is firmly attached to the skull. This makes for a very rigid, inflexible construction.

The tip of the upper jaw is beak-like and separated from the remainder of the jaw by a notch. There is a single row of teeth in the lower jaw and a double row in the upper, with the bottom row fitting perfectly between the two upper rows when the mouth is closed. This specific tooth arrangement is not seen in any other reptile. The jaws chew with backwards and forwards movements combined with a shearing up and down action. As their teeth wear down, older tuatara have to switch to softer prey such as earthworms, larvae, and slugs, and eventually have to chew their food between smooth jaw bones.

These are just some of the physical features which differentiate tuataras from squamata (lizards and snakes). If you wish to read more just check out the wikipedia page on these amazing animals [x]

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Tuatara (Sphenodon punctatus)

  • The tuatara is famous because it is the only survivor of an ancient group of reptiles that roamed the earth at the same time as dinosaurs
  • It hasn’t changed much in over 225 million years. The relatives of the tuatara died out about 60 million years ago which is why the tuatara is called a ‘living fossil’
  • This species survived in New Zealand for over 100 million years but rats and people drove them to extinction there
  • Today they live in well defended burrows on only 37 off-shore islands and mainland islands like the Karori Sanctuary
  • The total tuatara population on all these islands is estimated to be between 50,000 and 100,000
  • There are two species. (Sphenodon punctatus) is the Cook Strait tuatara which live on Stephen’s Island in the Marlborough Sounds and the Brother’s Island tuatara (Sphenodon guntheri). There are much fewer of the second species. They are slightly smaller than the other tuatara and lived ONLY in a patch of scrub on the top of tiny North Brother Island in the Marlborough Sounds.
  • The Northern tuatara, (Sphenodon punctatus punctatus), is a sub-species which live on offshore islands around the north of the North Island
  • Tuataras can live to be over 100 years old and grow very slowly (they only stop growing at 35 years old)
  • The color of tuatara ranges from olive green to brown to orange-red, and they can change color over their lifetime
  • They can hold their breath for an hour
  • They shed their skin once a year
  • This species is not actually defined as a lizard
  • Male tuataras are bigger than the female and have a more prominent crest of spines along its back. They both become sexually mature when they are 15 to 20 years old
  • A female will be ready to mate only once every two to five years
  • The male will sit outside her burrow and wait. If she is interested they will mate and 8 or 9 months later she will lay and bury 6 to10 eggs in a sunny place. 11 to16 months later the baby tuatara will hatch.
  • Like many reptiles which lay eggs in a nest; temperature decides which sex the eggs will become. The warmer the soil, the greater chance for males.
  • Scientists at Victoria University found that at 22° C, 80% of tuatara incubated would hatch into males, at 20° C, 80% were likely to be females and at 18° C, all the tuatara hatched were female.
  • If global warming continues all Tuatara eggs will be males and the entire beautiful species will go extinct

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