Aldonaia (IMAGE) University of Leeds Caption This is a fossilized trilobite Aldonaia from the Cambrian Period Credit Andrey Zhuravlev, Lomonosov Moscow State University Usage Restrictions Credit must be given 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.