Oyster Parasite Acts as Natural Timepiece (IMAGE) Florida Museum of Natural History Caption The impressed odostome, Boonea impressa, is a tiny marine snail that parasitizes oysters by perching atop and piercing their shells and sucking their insides. Because the snails have a predictable 12-month life cycle, their length can record the time of death of their oyster host, allowing researchers to date ancient oyster harvesting. Credit Kristen Grace/Florida Museum Usage Restrictions Please credit Kristen Grace/Florida Museum 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.