The hyperdiverse group of venomous Conoidea has eluded attempts to construct a robust and stable classification owing to the absence of a robust and stable phylogenetic framework. New molecular data have greatly enhanced our understanding of conoidean evolution, allowing the construction of a new family-level classification. This expanding framework has also allowed the discovery of several independent lineages that merit recognition at familial rank. One of these, based on seven specimens collected over more than 20 years from deep waters off New Caledonia, represents a unique, monotypic lineage closely related to Mitromorphidae, which we here name as the new family Bouchetispiridae. This new lineage bears a unique combination of teleoconch, protoconch and anatomical characters previously unknown within the Conoidea, including a translucent, fusiform shell with sculpture of strong axial ribs crossed by spiral cords, a multispiral protoconch of only 2.5 whorls with punctate sculpture, hypodermic marginal teeth and a multilayered venom bulb with two layers of muscle separated by connective tissue. This lineage may represent the sole survivor of a previously more diverse clade, or is simply one of many unique taxa that have arisen among the isolated sea mounts off New Caledonia.