Ifremeria nautilei is a species of large, deepwater hydrothermal vent sea snail, a marine gastropod mollusk in the family Provannidae, and the only species in the genus Ifremeria. This species lives in the South Pacific Ocean Other species in the family Provannidae live in similar deepwater hydrothermal vent habitats. As is the case in species in the genus Alviniconcha, the tissues of Ifremeria nautilei contain symbiotic bacteria which live on the sulfur from the vents, and the snails derive their nutrition from this symbiosis.