Truncatellidae

Truncatellidae, common name the "looping snails", is a family of small amphibious snails, with gills and an operculum, semi-marine gastropod mollusks or micromollusks.

Truncatellidae
Two live individuals of Truncatella subcylindrica: a juvenile on the left, and an adult on the right
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
Subclass:	Caenogastropoda
Order:	Littorinimorpha
Superfamily:	Truncatelloidea
Family:	Truncatellidae Gray, 1840[1]

Shell description

Drawing of a shell of Truncatella bilabiata

This family of snails have small shells which lose their apical whorls as they continue to grow, giving the shells a truncated and cylindrical appearance.

Subfamilies

The family Truncatellidae consists of two subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005):^[2]

• subfamily Truncatellinae Gray, 1840
• subfamily Geomelaniinae Kobelt & Möllendorff, 1897^[3]

Genera

Genera within the family Truncatellidae include:

Truncatellinae

• Truncatella Risso, 1826^[4] - type genus of the family Truncatellidae^[2]

Geomelaniinae

• Geomelania L. Pfeiffer, 1845 - type genus of the subfamily Geomelaniinae^[2]

subfamily ?

• †Nystia
• Taheitia Adams, 1863^[4]

Habitat

Snails in this family are found in marine coastal environments, near or just above the high tide line on stones and pebbles, fine sediments and decomposing vegetation.

Life cycle

The sexes are separate. Fertilized eggs are laid as egg capsules, which are attached to detritus.