Tuatara (Sphenodon, endemic to New Zealand), Taronga Zoo, Sydney, Australia.
New Zealand Tuatara (Genus: Sphenodon), Taronga Zoo, Sydney, New South Wales (NSW), Australia. The two species of tuatara are the only surviving members of its order Sphenodontia, which flourished around 200 million years ago. Although sometimes called "living fossils," they have changed significantly since the Mesozoic era. Tuatara share a common ancestor with the squamates (lizards and snakes) and are of great interest in the study of the evolution of lizards, snakes, and diapsids (dinosaurs, birds, and crocodiles). Tuatara are greenish brown, and measure up to 80 cm (31 in) from head to tail-tip and weigh up to 1.3 kilograms (2.9 lb) 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 have an unusual photo-receptive "third eye," can hear without an external ear, and have skeletal features apparently evolved from fish. Tuatara, like many of New Zealand's native animals, are threatened by habitat loss and introduced predators like the Polynesian Rat.Add to Cart Add to Lightbox Download