The fig shells, a small group of relatively large marine snails, make up the small family Ficidae (Gastropoda), which is comprised of two genera. Genus Ficus has 10 species, found from the intertidal to depths up to 1000m (3000 feet) in warm and temperate waters around the world; the less common genus Thalassocyon inhabits the Southern Hemisphere, found only in deep waters (up to 3000 m; 10,000 feet) off the coast of South Africa, New Zealand, and Amsterdam Island. Thalassocyon includes between 1-3 species, for which the synonymy is unclear (Warén and Bouchet 1990 and Riedel 2000, as cited in Vos 2013). The two genera have been revised as sister taxa in family Ficidae based of shared radula shape and the ridge (keel) along the edge of their body whorl; Thalassocyon was originally classified into gastropod family Cymatiidae.
(Beu 1969; Neo 2010; Vos 2013)