Team discovers a new invasive clam in the US

They found it in the Illinois River near the city of Marseilles, Illinois, about 80 miles west of Lake Michigan - a strange entry point for an invasive Asian clam. The scientists who found it have no idea how it got there. But the discovery - along with genetic tests that confirm its uniqueness - means that a new species or "form" of invasive clam has made its official debut in North America.