Carl Simpson (IMAGE) University of Colorado at Boulder Caption Carl Simpson inspects a fossil of Brooksella alternata, an invertebrate animal that swam in the ocean roughly 500 million years ago. Credit Glenn Asakawa/CU Boulder Usage Restrictions Credit must be given to the creator. License CC BY 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.