Tuatara
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The tuatara is an endangered species who lives on the islands of New Zealand. At first glance you might think its just a lizard; however, it is not. There are some major differences between them. The most notable of which is its "third eye". It is a reptile, and like all others, it forms amniotic eggs. It prefers colder weather than the usual tropical or desert temperatures. The tuatara is a living fossil. There are only two species living today.
Anatomy
The anatomical differences between tuataras and lizards start with the row of sharp spines running down the back of the tuatara. Males expand them to show their size and impress the females when they are ready to mate. The spines are also larger on the male than females. Another difference that distinguishes them from the lizard is their teeth. One row of teeth on the bottom jaw fits between two rows on the top jaw. However, the most striking difference is their "third eye." In the first six months of a tuatara's life it has a visible parietal eye. It is light sensitive, drawing in ultraviolet rays. It is believed that this occurs because the tuatara uses the UV rays to make vitamin D, for their growth. After the six months scales will cover the eye.
Like other reptiles, tuataras have rough scales and sharp claws. Its feet are slightly webbed and good for swimming. The tuatara also has no open ear holes however they do have a middle ear cavity that is made of loose tissue. Tuataras are ectothermic like other reptiles.
Reproduction
Tuataras mate every two to five years. When a male spots a female he will extend its spines and begin circling around her. If the female agrees then they will mate. Like all reptiles they produce amniotic eggs. After about sixteen months the baby will be born. The baby must then wait fifteen to twenty years to reach sexual maturity. Tuataras can generally live between sixty to one hundred years old. The temperature at which the egg is will affect the sex of the baby. Warmer eggs will produce male tuataras and colder eggs will be female. At 20 degrees Celsius the percentage of being female is 80%. The percentage of being male at 22 degrees is 80%. At 21 degrees it is 50/50.
Ecology
The tuatara is in danger of becoming extinct. The species Sphenodon punctatus number to 50,000 and the species Sphenodon guntheri number to a mere 400 adults. Adult tuataras are nocturnal creatures who live on the ground. A baby tuatara will live in trees and be diurnal. This is because adult tuataras are known eat their babies. Tuataras are excellent swimmers because of their webbed feet and their ability to hold their breath for almost an hour. Tuataras eat insects and small birds. Tuataras will even burrow with some birds; however, it will eat the bird if it is hungry enough. Tuataras like to live in cold weather of 16-21 degrees Celsius on the islands of New Zealand. This is the only place in the world that tuataras are found. Tuataras enjoy killing rodents.
Living fossil
- Main Article: Living fossil
According to evolutionist interpretations of the fossil record, the tuatara has remained largely unchanged for 200 million years. This places the tuatara alongside dinosaurs in the Mesozoic era. Despite this, scientists have been surprised to find that the tuatara is the "fastest evolving" creature on the genetic level. This is based upon comparisons between modern and fossil tuatara DNA. The finding brings into question a close connection between genetic change and physical change, and between genetic change and reproductive rate.
References
- Tuatara Wikipedia
- Tuatara The Kiwi Conservation Club
- TuataraDepartment of Conservation Te Papa Atawbai
- Fastest Evolving Creature is 'Living Dinosaur' Live Science
