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Bodyplan
A beautiful view of the mountains.




Tuataras have a bodyplan that-at first-resembles that of a lizard. They have the typical lizard body complete with four well developed limbs and a relatively long tail. But tuataras are not lizards.

For one tuataras lack external ears. They have hooklike extensions on some of their ribs (which can also be found in birds) and males lack a penis (another birdy trait).

Tuataras also have a pineal or "third eye" on the top of their heads. Although this "eye" is also found on lizards and is comprised of a lens, retina and nerve connection to the brain. In lizards this pineal eye is used for temperature regulation, giving the animals a fairly good idea of the surrounding temperature and allowing them to know when they are too hot or too cold. Since tuataras are nocturnal forest dwellers it is harder to say what their pineal eye is used for.

Males and females are sexually dimorphic with males being much larger and heavier. Males also have prominent nuchal and dorsal crests along with narrower abdomens than females.

Tuataras are also capable of caudal autotomy, just like many lizards.

Chewers

Tuataras have a two rows of teeth on their top jaws and one row on the bottom. When the jaws are shut, the bottom row fits neatly inbetween the two top rows. When eating the Tuatara will actually slide it's jaw back and forth, grinding up it's meals. This back and forth chewing is different from the rotational side to side like chewing found in mammals, showing us that this trait was independantly evolved in at least one genus of rhynchocephalians.


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