Radotina (IMAGE) Uppsala University Caption A tropical reef in the Czech Republic, 409 million years ago: Radotina, one of the most primitive jawed vertebrates with teeth, emerges from its hiding place in the empty shell of a giant nautiloid to hunt for food. Credit Jan Sovak Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.