One of the most unusual lizards left on this planet is the Tuatara of New Zeland. Opisthias is an ancestor of this true "living fossil" and likely looked very similar. The Sphenodon's are currently represented by only the Tuatara, but that was not always the case. These "lizard-like" reptiles are not true lizards but are in fact a side-path of evolution that started in the Middle Triassic and continue down to the one species left today. Some relatives took to the water and became known as the pleurosaurs. Others were very similar to today's living fossil, in fact the same basic body type and lifestyle has been running virtually unchanged for nearly 200 million years.