Editing Sea butterfly (section)

==Taxonomy==
Along with its sister group, the sea angels ([[Gymnosomata]]), the sea butterflies (Thecosomata) are included in the [[order (biology)|order]] [[Pteropoda]].<ref name=Hunt-2007/>
The validity of the [[pteropod]] order is not universally accepted; it fell out of favour for a number of years, but recent molecular evidence suggests that the taxon should be revived.<ref>
{{cite journal
 | last1 = Klussmann-Kolb | first1 = A.
 | last2 = Dinapoli       | first2 = A.
 | year = 2006
 | title = Systematic position of the pelagic Thecosomata and Gymnosomata within Opisthobranchia (Mollusca, Gastropoda) - revival of the Pteropoda
 | journal = Journal of Zoological Systematics and Evolutionary Research
 | volume = 44 | issue = 2 | pages = 118
 | doi = 10.1111/j.1439-0469.2006.00351.x
| doi-access = free
 }}
</ref> 
Although most Thecosomata have some form of calcified [[gastropod shell|shell]], mature Gymnosomata have none.<ref name=Hunt-2007/>

=== Ponder & Lindberg ===
Order '''Thecosomata''' <small>[[de Blainville]], 1824</small>
* Infraorder [[Euthecosomata]]
** Superfamily [[Limacinoidea]]
*** Family [[Limacinidae]] <small>[[de Blainville]], 1823</small>
** Superfamily [[Cavolinioidea]]
*** Family [[Cavoliniidae]] <small>H. and A. Adams, 1854</small>
*** Family [[Cliidae]]
*** Family [[Creseidae]]
*** Family [[Cuvierinidae]]
*** Family [[Praecuvierinidae]]
* Infraorder [[Pseudothecosomata]]
** Superfamily [[Peraclidoidea]]
*** Family [[Peraclidae]] <small>Tesch, 1913</small>
** Superfamily [[Cymbulioidea]]
*** Family [[Cymbuliidae]] <small>[[John Edward Gray|Gray]], 1840</small>
*** Family [[Desmopteridae]] <small>[[W.H. Dall|Dall]], 1921</small>

=== Bouchet & Rocroi ===
In the new [[Taxonomy of the Gastropoda (Bouchet & Rocroi, 2005)|taxonomy of Bouchet & Rocroi]] (2005) Thecosomata is treated differently :

'''Clade Thecosomata :''' <ref name="Thecosomata">{{cite book | title=Pseudothecosomata, Gymnosomata and Heteropoda (Gastropoda)| last=van der Spoel| first=S.| year=1976| pages=484 pp| publisher=Bohn, Scheltema & Holkema| location=Utrecht | isbn=90-313-0176-0}}</ref>
*Superfamily Cavolinioidea <small> Gray, 1850 </small> ( = Euthecosomata)
**Family Cavoliniidae <small> Gray, 1850 (1815) </small>
***Subfamily Cavoliinae  <small> Gray, 1850 (1815) </small> (formerly Hyalaeidae <small> Rafinesque, 1815 </small>)
***Subfamily Clioinae <small> Jeffreys, 1869 </small> (formerly Cleodoridae <small> Gray, 1840 </small> - ''nomen oblitum'')
***Subfamily Cuvierininae <small> van der Spoel, 1967 </small> (formerly : Cuvieriidae <small> Gray, 1840 </small> (nom. inv.); Tripteridae <small> Gray, 1850 </small>)
***Subfamily Creseinae <small>Curry, 1982 </small>
**Family Limacinidae <small> Gray, 1840 </small> (formerly : Spirialidae <small> Chenu, 1859 </small>; Spiratellidae <small> Dall, 1921 </small>)
** † Family Sphaerocinidae <small> A. Janssen & Maxwell, 1995 </small>
*Superfamily Cymbulioidea <small> Gray, 1840 </small> ( = Pseudothecosomata)
**Family Cymbuliidae <small> Gray, 1840 </small>
***Subfamily Cymbuliinae <small> Gray, 1840 </small>
***Subfamily Glebinae <small> van der Spoel, 1976 </small>
**Family Desmopteridae <small> Chun, 1889 </small>
**Family Peraclidae <small> Tesch, 1913 </small> (formerly Procymbuliidae <small> Tesch, 1913 </small>

Bouchet & Rocroi (2005) move the family Limacinidae into the superfamily Cavolinioidea, making redundant the superfamily Limacinoidea erected for it in Ponder & Lindberg's taxonomy. The families Creseidae and Cuvierinidae are demoted to subfamilies of Cavoliniidae (Creseinae and Cuvierininae). The infraorder Pseudothecosomata becomes the superfamily Cymbulioidea. The family Peraclididae is included in the superfamily Cymbulioidea as the family Peraclidae, making the superfamily Peraclidoidea redundant.