Ostracod Shells (IMAGE) Shinshu University Caption Ostracod shells from juvenile to adult used for analysis. Ostracod is an arthropod that has lived for 500 million years. (photo by Kentaro Kuroki of Yamada lab.) Credit Katsura Yamada, Shinshu University, Japan 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.