Assimineidae

Assimineidae is a family of minute snails with an operculum, gastropod mollusks or micromollusks in the superfamily Rissoidae. Many of these very small snails live in intermediate habitats, being amphibious between saltwater and land; others live in freshwater. The distribution of the Assimineidae is worldwide. Various species in this family occur in estuarine habitats, in salt marshes and in freshwater. Some are terrestrial or amphibious. The shell is small to medium large, more or less egg-conelike shaped. The apertural margin is simple. The operculum is in most cases horny. Species in this family are characterized by rudimentary cephalic tentacles, a trunklike snout, a foot with a groove and rudimentary to absent ctenidium (a comb-like respiratory apparatus). The following three subfamilies were recognized in the taxonomy of Bouchet & Rocroi (2005): Genera in the family Assimineidae include: