Tuatara (Rhynchocephalia) are a rare group of reptiles that inhabit the rocky islands off the coast of New Zealand. Today, tuatara are the least diverse group of reptiles, with only two living species.
Tutatara were once more widespread and diverse than they are today. Fossil evidence shows that their range once included present-day Europe, Africa, South America and Madagascar. There were as many as 24 different genera of tuatara but most of those disappeared by about 100 million years ago.
Tuatara are nocturnal burrowing reptiles that inhabit coastal forests where they forage over a home range and feed on bird eggs, chicks, invertebrates, amphibians, and small reptiles. Since they are cold-blooded and live in cool habitats, tuatara have low metabolic rates. They grow slowly and have a long lifespan. Tuatara are known to reproduce until they are 60 years old. No one knows exactly how long they live beyond that.
Tuatara are diapsids, a group of reptiles that possess two holes (or temporal fenestra) on each side of their skull. Tuatara have two rows of teeth in their upper jaw and one row of teeth in their lower jaw. This arrangement of teeth is unique to tuatara. Tuatara have a parietal eye, a light-sensitive spot located on the top of the animal's head which is thought to play a role in setting circadian rhythms.
The first tuatara appeared during the Mesozoic Era, about 220 million years ago, about the same time the first dinosaurs appeared. The closest living relatives of the tuatara are the squamates.
The key characteristics of tuatara include:
- slow growth and low reproductive rates
- reach sexual maturity at 10 to 20 years of age
- diapsid skull with two temporal openings
- prominent parietal eye on top of head
Turtles are classified within the following taxonomic hierarchy: