The taxon Pulmonata as traditionally defined was found to be polyphyletic in a molecular study per Jörger et al., dating from 2010.
[2] Pulmonates have a single atrium and kidney, and a concentrated symmetrical nervous system.
The mantle cavity is on the right side of the body, and lacks gills, instead being converted into a vascularised lung.
Jörger et al. (2010)[1] analyzed major groups within the Heterobranchia using genetic data and found that Pulmonata as traditionally defined was polyphyletic, for instance some pulmonates were more closely related to Sacoglossa and Acochlidia.
They proposed the more inclusive taxon Panpulmonata to unite the clades Siphonarioidea, Sacoglossa, Glacidorboidea, Pyramidelloidea, Amphiboloidea, Hygrophila, Acochlidia and Eupulmonata.