Didemnum Vexillum (IMAGE) University of Barcelona Caption The study reveals 44% marine invertebrate Didemnum vexillum colonies in Ebro Delta (Tarragona, Spain) are chimera formed by parts with distinct gene pools. Credit Xavier Turon (CEAB-CSIC) Usage Restrictions The image may only be used with appropriate caption or credit. 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.