Clionidae


The Clionidae are a family of sea angels, which are a group of pelagic marine gastropods.
They resemble angels, complete with flapping "wings", hence their common name. They are gelatinous, mostly transparent pteropods, and they only have shells in their embryonic stage. They are mostly very small, with the largest species reaching.

External anatomy

The Clionidae use winglike flaps for rhythmical locomotion, as if flying in the sea. These "wings" are attached to the anterior part of the body. The posterior part is gelatinous and mostly transparent.
The orange visceral sac is confined to the anterior part.

Life habits

Mating is carried out ventrally for mutual fertilization. The following spring, this results in a free-floating, gelatinous egg mass.

Taxonomy

Clionidae d'Orbigny, 1851 is unfortunately also the name of a family of sponges in the order Hadromerida, class Demospongiae. Within the ICZN there has been a proposed emendation of spelling to Clionaidae for the sponge family. The ICZN has ruled the correct name of gastropod family is Clionidae Gray, 1847, with type genus Clione Pallas, 1774.
These two subfamilies have been recognized in the taxonomy of Bouchet & Rocroi :
Genera within the family Clionidae include:
subfamily Clioninae
subfamily Thliptodontinae
subfamily ?