Tua-what-a?

Tuatara (n.)- Maori word for "peaks on the back"

The Tuatara is a 200 million year old native of New Zealand that closely resembles a lizard. Though they resemble lizards superficially, that is about all they have in common. The tuatara is considered the most unspecialized living amniote, and can live 60-100 years in the wild. It's brain and mode of locomotion is like that of amphibians, it has a more primitive heart than any other reptile, very primitive hearing, and their lungs have only one chamber and no bronchi. The peak activity levels for tuatara is between 12 and 17 degrees Celsius, the lowest of any reptile.

The tuatara has unique dentition. The lower teeth fit into a groove between 2 rows of upper teeth. This isn't seen in any other animal in the world.

The tuatara has a parietal or third eye on the top of its head. It grows under the skin of adults and some scientists argue it serves no function, though it's retina and rudimentary lens suggests it affects the hibernation and sleep cycle of the tuatara.

For all these reasons, the tuatara is especially of interest to evolutionary biologists, since they serve as a "living fossil" that can help scientists understand the evolutionary relationships between living reptiles, as well as extinct orders of reptiles. The tuatara is the only living member of the order Rynchocephalia.