In biological nomenclature, a nomen novum, new replacement name is a technical term. It indicates a scientific name that is created specifically to replace another scientific name, but only when this other name cannot be used for technical, nomenclatural reasons ; it does not apply when a name is changed for taxonomic reasons. It is frequently abbreviated, e.g.nomen nov., nom. nov..
Hydrobiidae, commonly known as mud snails, is a large cosmopolitan family of very small freshwater and brackish water snails with an operculum; they are in the order Littorinimorpha.
Oxychilus is a genus of small air-breathing land snails, terrestrial pulmonate gastropods in the family Oxychilidae, the glass snails.
Candidula is a genus of air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Geomitridae, . the hairy snails and their allies.
Cochlicopa, whose species are known as pillar snails, is a genus of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Cochlicopidae.
Cochlostoma is a genus of land snails with an operculum, terrestrial gastropod mollusks in the family Cochlostomatidae.
Gulella is a genus of very small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Streptaxidae.
Melanopsis is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Melanopsidae.
Paludinella is a genus of minute salt marsh snails with an operculum, aquatic gastropod mollusks or micromollusks, in the family Assimineidae.
Pseudamnicola is a genus of small brackish water snails with an operculum, aquatic gastropod mollusks in the family Hydrobiidae.
Valvata is a genus of very small freshwater snails with an operculum, aquatic gastropod mollusks in the family Valvatidae, the valve snails.
Cyclophorus is a genus of operculate land snails, terrestrial gastropod mollusks in the family Cyclophoridae.
Rissoina is a large genus of minute sea snails, marine gastropod mollusks or micromollusks, in the family Rissoinidae.
Eulima is a genus of small, ectoparasitic sea snails, marine gastropod mollusks in the family Eulimidae.
Gomphroa is a genus of small air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Azecidae.
