Head to head: Living fossils
Although previously thought to be extinct, two species of coelacanth have remained virtually unchanged for 300 million years.
Ancient relatives of starfish, crinoids dominated the seas some 450 million years ago and still, in fact, exist in the oceans today.
Members of the nautiloid group – a type of cephalopod – appeared in the fossil record 500 million years ago and have changed very little since.
To learn more about all the incredible animals on our planet, why not visit our AnimalAnswers website – from the makers of How It Works.