Pyrgulopsis


Pyrgulopsis is a genus of freshwater snails with a gill and an operculum, aquatic gastropod mollusks in the family Hydrobiidae.

Etymology

The name Pyrgulopsis is composed from Pyrgula, another genus of snail, and opsis = :wiktionary:aspect|aspect of.

Description

Generic characters of the genus Pyrgulopsis are: the shell is minute, conically turreted, somewhat elongated, imperforate and unicarinate. The apex is acute. The aperture is ovate. The edge of the aperture, called the peritreme, is continuous. The operculum is ovate, thin, corneous and spiral, with polar point well forward and approximating the columella.
The jaw is thin and membranaceous. The radula is odontophore, with teeth are arranged in transverse rows, according to the formula 3 + 1 + 3. Formula for denticles of rhachidian:.

Distribution

The distribution of the genus Pyrgulopsis includes Western and South-western United States. Snails of species in the genus Pyrgulopsis occur in fresh water and in brackish water.

Species

Pyrgulopsis is the largest genus of freshwater gastropods in the North America. In 2014, 139 species were recognized in this genus.
Species in the genus Pyrgulopsis include:
Eastern North American species of Pyrgulopsis are considered to be in separate genus Marstonia according to the Thompson and Hershler.