''Basilissopsis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Seguenziidae Seguenziidae is a family (biology), family of very small deepwater sea snails, marine (ocean), marine gastropod mollusks in the superfamily Seguenzioidea (according to the Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005), taxonomy of the Gastr ...

. In 1897 Dautzenberg and

Fischer Fischer is a German occupational surname, meaning fisherman. The name Fischer is the fourth most common German surname. The English version is Fisher. People with the surname A * Abraham Fischer (1850–1913) South African public official * ...

created this new genus for their specimen of ''Basilissopsis watsoni'', based on the shell characteristics of discolored specimens that were non-nacreous and lacked labral sinuses. This was however contradicted later by the discovery of other species in this genus that possess nacre and labral sinuses. This puts this genus in the family

Description

Nothing is known of the anatomy of the soft body in these species. The conical shell has peripheral carina and collabral axial riblets. All

whorl A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). In nature File:Photograph and axial plane floral diagra ...

s contain midwhorl angulation but spiral lirae are absent. The U-shaped posterior sinus is shallow. There is no anterolateral sinus. A basal sinus is present. A columellar sinus is lacking. The

aperture In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...

has a rhomboidal shape. A columellar tooth is lacking. The

umbilicus Umbilicus may refer to: *The navel or belly button *Umbilicus (mollusc), a feature of gastropod, Nautilus and Ammonite shell anatomy *Umbilicus (plant), ''Umbilicus'' (plant), a genus of over ninety species of perennial flowering plants *Umbilicus ...

contains a septum. The shell has no microsculpture. There are no data about the

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

Species

Species within the genus ''Basilissopsis'' include: * '' Basilissopsis athenae'' Hoffman, Gofas & Freiwald, 2020 *'' Basilissopsis bassa'' Lima, Christoffersen & Villacampa, 2014 *'' Basilissopsis charcoti'' Marshall, 1991 *'' Basilissopsis hakuhoae'' Kurihara & Ohta, 2008 *'' Basilissopsis oxytropis'' ( Watson, 1879) *''

Basilissopsis regina ''Basilissopsis regina'' is a species of extremely small deep water sea snail, a marine gastropod mollusk in the family Seguenziidae.WoRMS (2013). ''Basilissopsis regina'' (Marshall, 1983). Retrieved through: World Register of Marine Species at ...

'' (Marshall, 1983) *'' Basilissopsis rhyssa'' ( Dall, 1927) * '' Basilissopsis vanheugteni'' Hoffman & Freiwald, 2017 *'' Basilissopsis watsoni'' Dautzenberg &

, 1897

References

* Marshall B.A. (1991). ''Mollusca Gastropoda : Seguenziidae from New Caledonia and the Loyalty Islands''. In A. Crosnier & P. Bouchet (Eds) Résultats des campagnes Musorstom, vol. 7. Mémoires du Muséum National d'Histoire Naturelle, A, 150:41–109. {{Taxonbar, from=Q4867462 Seguenziidae Gastropod genera Taxa named by Paul Henri Fischer