What is "kuphus"

Kuphus is a genus of shipworms, marine bivalve molluscs in the family Teredinidae. There are two extinct species in the genus, Kuphus incrassatus and Kuphus fistula. The only extant species is Kuphus polythalamia, the longest bivalve mollusc in the world.

Members of this genus secrete calcareous tubes. Based only on the calcareous tube, this species was thought by Linnaeus to be a tube worm, so he placed it in the genus Serpula. Despite the fact that Kuphus polythalamia is now known to be a mollusc, its common name is the giant tube worm. Since 1981 however, the name "giant tube worm" has also been applied to the hydrothermal vent species Riftia pachyptila, which is indeed a worm, an annelid.