Digging 3 meters down into the dark marine mud of a former log storage pond in Mindanao, Philippines, scientists have discovered five live specimens of an elusive creature previously known only through the 1 to 1.5–meter-long calcium carbonate shells it left behind.

By carefully chipping away at the end of a chalky tube (right, above), researchers found a long, black, wormlike mass oozing from its casing – the first live specimen of the giant shipworm Kuphus polythalamia. The animal’s length makes it the longest of any living bivalve, a class of typically small critters including clams, oysters, and scallops. And as far as shipworms go, which usually burrow into and feed on wood from ships or sunken trees, K. polythalamia is unique for squa ...