Caught! (IMAGE) University of Iowa Caption Biologists led by the University of Iowa used a special technique called eDNA to discover an invasive species of tiny snails in streams in central Pennsylvania where the snails' presence had been unknown. The invasive New Zealand mud snail has spread to the Eastern Seaboard after arriving in the western United States decades ago. Credit Edward Levri, Pennsylvania State University-Altoona 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.