Stages of Copepod (IMAGE) U.S. National Science Foundation Caption The copepod Acartia tonsa has 13 developmental stages, from egg through adult (clockwise). Credit David Elliott 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.