Trochida is an order of small to very large vetigastropod, Recent and extinct

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

s with

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

s and an operculum.MolluscaBase (2018). Trochida. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1052448 on 2019-01-06

Taxonomy

Still existing trochomorphs stem from a large, archaic

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

. According to Uribe ''et al.'' (2016) the superfamilies Angarioidea and Phasianelloidea are deeply nested within the superfamily Trochoidea sensu Williams (2012).Williams, S.T., 2012, ''Advances in molecular systematics of the vetigastropod superfamily Trochoidea.'' Zoologica Scripta, 41(6): 571–595. The revised taxonomy (2017) of Bouchet ''et al.'' therefore only recognizes the superfamily Trochoidea (including Angarioidea and Phasianelloidea).

Superfamilies

* Trochoidea Rafinesque, 1815 ;Synonyms: * Angarioidea Gray, 1857: synonym of Trochoidea Rafinesque, 1815 * Phasianelloidea Swainson, 1840: synonym of Trochoidea Rafinesque, 1815

References

* Bouchet P., Rocroi J.P., Hausdorf B., Kaim A., Kano Y., Nützel A., Parkhaev P., Schrödl M. & Strong E.E. (2017). Revised classification, nomenclator and typification of gastropod and monoplacophoran families. Malacologia. 61(1-2): 1-526 {{Taxonbar, from=Q58192325 Vetigastropoda