Trochoidea is a superfamily of small to very large vetigastropod sea snails with gills and an operculum. Species within this superfamily have nacre as the inner shell layer. The families within this superfamily include the Trochidae, the top snails. This superfamily is the largest vetigastropodan superfamily, containing more than 2,000 species. This taxon is not the same as a pulmonate land snail genus which is spelled the same way: Trochoidea (genus).

Taxonomy

2005 taxonomy

This superfamily consisted of nine following families (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005):

2017 taxonomy

Williams et al. (2008) have made further refinements to the taxonomy of Trochoidea. The revised taxonomy as defined by Bouchet et al. (2017) resulted in the following families. The fossil families, tentatively included in this list, are based on Tracey et al. (1993) Unassigned to a family: