What is it? It is an invertebrate (a creature with no backbone). It had a body with an outer skeleton. The body had three different segments, called lobes. When did it live? Sometime in a period from 345 to 315 million years ago. Is this type of creature extinct? Yes. They have been extinct for more than 200 million years. But at one time there were of 10,000 different species of this creature. Where did it live? All of these creatures were marine. They swam or skimmed over the bottom of the sea, lay upon it, and plowed through the sand or mud. How did it eat? What did it eat? Many types burrowed into rubbish, which provided them with food.