The family Cavoliniidae is a taxonomic group of small floating sea snails, pelagic marine opisthobranch gastropod mollusks. This family is part of a larger group which is commonly known as the sea butterflies because they swim by flapping what appear to be small "wings".

Distribution

This family of sea butterflies are circumglobal, carried by the sea currents to all the seas of the world.

Habitat

Cavoliniids prefer deep waters, from 100 m down to 2,000 m. They do best in warm oceanic water.

Life habits

Towards the anterior end of the animal, two parapodia (winglike flat lobules) protrude between each half of the shell. The parapodia enable these sea butterflies to float along in the water currents, using slow flapping movements. The parapodia are also covered with cilia, which produce a minute water current that pushes the planktonic food to the mouth of the animal.

Taxonomy

In 2003, the family Cavoliniidae was raised to the rank of superfamily Cavolinioidea. At the same time, the subfamilies were given the new status of families: Cavoliniidae, Cliidae, Creseidae and Cuvierinidae.

2005 taxonomy

In the taxonomy of Bouchet & Rocroi (2005) several families have been categorized as subfamilies of the family Cavoliniidae:

Genera

Genera in the family Cavoliniidae include: Genus Cavolinia Abildgaard, 1791 – A very distinctive shape of shell with a marked bulge on the ventral plate. The species consists of protandric hermaphrodites. Genus Diacavolinia van der Spoel, 1987 Twenty two species of Diacavolinia. Diacavolinia species are characterised by the absence of a caudal spine Genus Diacria J. E. Gray, 1847 The genus comprises two species groups and a total of ten species. The species may be globular, with both dorsal and ventral sides rounded, or bilaterally symmetrical with a long caudal spine. The species are protandric hermaphrodites. They are the largest of the Cavoliniids.

Clioinae

Clioinae Jeffreys, 1869 = Family Cliidae Jeffreys, 1869 This family name has for a long time been Clioidae with the type genus Clio. Unfortunately this is often confused with another molluscan family Clionidae, which has the type genus Clione. The International Commission on Zoological Nomenclature (ICZN) has therefore changed the name back to its original spelling Cliidae Jeffreys, 1869, type genus Clio Linnaeus, 1767 Genus Clio Linnaeus, 1767 (synonyms: Cleodora Peron & Lesueur, 1810 ; Euclio Bonnevie, 1912 ) All species in this genus are characterised by a bilaterally symmetric, straight or adapically dorso-ventrally slightly curved shell, with an elliptical to triangular transverse section; protoconch clearly separated, globular or elliptical, frequently with a spine at the tip. Subgenera are used for some species (e.g. Clio s.str., Balantium Bellardi, 1872, Bellardiclio Janssen, 2004) , but most species cannot yet be assigned to one of these. Numerous fossil species have been described. Recognised extant species are: Formae: The true status of these formae has to be evaluated, they might be real formae, subspecies, or even species.

Cuvierininae

This subfamily has been raised to the rank of family Cuvierinidae van der Spoel, 1967 Extinct genera: Extant genera: The genus Cuvierina developed from the Ireneia lineage during the Early Miocene and is split in two subgenera: Extant species: Extinct species: Extant species: Extinct species:

Creseinae

Creseinae Curry, 1982 Genus Creseis Rang, 1828 This subfamily has been raised to the rank of family Creseidae, belonging to the superfamily Limacinoidea. The shells of the species in this genus have the form of a more or less narrow, conically widening tube. Genus Hyalocylis Fol, 1875 Genus Styliola Gray, 1850 (synonyms: Cleodora recta Blainville, 1825 ; Cleodora subula Quoy & Gaimard, 1827 (basionym); Creseis spinifera Rang, 1828 )