Euthyneura is a taxonomic clade of snails and slugs, which includes species from freshwater, marine, aquatic and terrestrial gastropod mollusks in the clade Heterobranchia. Euthyneura are considered the crown group of Gastropoda, and are characterised by several autapomorphies, but are named for euthyneury. They are considered to be the most successful and diverse group of Gastropoda. Within this taxon, the Gastropoda have reached their peak in species richness and ecological diversity. This obvious evolutionary success can probably be attributed to several factors. Marine Opisthobranchia, e.g., have evolved several clades specialised on less used food resources such as sponges or cnidarians. A key innovation in the evolution of Pulmonata was the colonization of freshwater and terrestrial