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.

Large, tusk-shaped, calcareous tubes were occasionally washed up on beaches. There was disagreement among zoologists in the 18th century as to whether the creature which made one of these was a polychaete tube-worm or came from a completely different phylum, the molluscs. Linnaeus described the species in 1758. He considered that it was a serpulid worm and named it Serpula arenaria, a name which in 1767 he changed to Serpula polythalamia. There was some confusion as to precisely which taxon he was describing, but S. polythalamia became the type species of the genus Serpula, a genus of polychaete worms. In 1770, Guettard introduced the name Kuphus for the genus, realising that the animal was not a worm but a mollusc. This meant that, according to the ICZN rules, the specific name became Kuphus polythalamia (Linnaeus, 1758).