Living Fossil Helped back to New Zealand Mainland

By | October 20th, 2007|Animal News Stories, Main Page|0 Comments

Tuatara Sanctuary receives new Residents

In the world today there are a few plants and animals that are relics from ancient history, they are often referred to as “living fossils”.  One such animal is the very rare Tuatara, an ancient reptile that superficially resembles a lizard but is in fact a member of the Order Sphenodontia and not part of the Order Squamata (lizards and snakes).  Tuatara is actually a Moari name, this animal is known by the genus Sphenodon (means wedge tooth), by scientists.  It is found on 32 remote islands off the coast of New Zealand, but a team of conservationists have been attempting to establish a colony on the mainland near Wellington.

Tuatara from Stephens Island in the Marlborough Sounds have been captured and are being re-homed at the Karori Wildlife Sanctuary, to help boost the numbers of these reptiles at this special preserve.  With the Stephens islands having an estimated population of 50,000 Tuatara, the removal of around 200 animals will not make much difference to the island’s population it will more than treble the Tuatara numbers at the Karori Wildlife Sanctuary.

The process of catching these animals, which can grow up to 60 cm long was not easy, as by day they live in burrows dug by petrels and rarely venture far from the burrow entrance during daylight.  Once grabbed the conservationists need to be mindful of the animals sharp teeth and claws.  Tuataras have a dental arrangement unique amongst terrestrial chordates, a sign of their ancient heritage.  They have a single row of teeth on the dentary (lower jaw) but two rows of teeth on the maxilla.  When the mouth is closed the lower jaw teeth fit perfectly into the space between the upper teeth rows, providing a very effective bite mechanism.  The animal seems to lack a predentary and the premaxilla forms a beak-like structure at the front of the mouth.

A male Sphenodon (Tuatara)

Picture courtesy of New Zealand Tuatara Conservation Team

We can tell it is a male from the picture as these animals demonstrate sexual dimorphism, the males are generally bigger than the females and the crest which runs down the spine is more pronounced in males than females.

In December 2005, the Karori Sanctuary became the home to 70 Tuatara, the first time these animals had made it back to the mainland for 200 years after going extinct in the 19th Century.  The new additions will help to strengthen the population and perhaps play a part in the re-introduction of these animals to other parts of New Zealand.

The lack of vermin, particularly rats will help the Tuatara, as these rodents eat the eggs of the reptiles and were largely responsible for their decline.  With luck, the two species of Tuatara still surviving will flourish and continue to provide a link between our world and the Triassic, as the Sphenodonts are first found in the fossil record dating back 220 million years.