Helicoidea

Helicoidea is a taxonomic superfamily of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the order Stylommatophora.

Taxonomy

The Bouchet et al. 2017 nomenclator provides an up to date system of Helicoidea. The system is in some parts preliminary, as the authors relied on unpublished phylogenomic study, which did not include all New World taxa. They classified Epiphragmophoridae, Helminthoglyptidae, Humboldtianidae, Monadeniidae and Xanthonychidae as subfamilies of the last taxon, because there are no deep splits between them in the cited unpublished study.
Cepolidae, Labyrinthidae and Thysanophoridae constitute the sister group of the remaining Helicoidea.

Razkin et al. reorganized classification into monophyletic taxa according to the molecular phylogeny. This study is focus on Western Palaearctic species. The Hygromiidae s.l. family was divided into three families, Canariellidae, Geomitridae and Hygromiidae. Moreover, the family Cochlicellidae was including within the Geomitridae family as a tribe.
The classification proposed for Western Palaearctic Helicoidea is as follows:

Thompson & Naranjo-García described a new family Echinichidae and placed it to the superfamily Xanthonychoidea. Therefore, the family Xanthonychidae was moved from Helicoidea to Xanthonychoidea.

There are 19 families within the superfamily Helicoidea according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005.

According to H. Nordsieck the family Xanthonychidae is probably polyphyletic and therefore should be divided into several families.