The atlas pebblesnail (''Somatogyrus humerosus'') is a species of minute

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...

snail that has an operculum, an aquatic operculate

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusk in the family Hydrobiidae. This species is endemic to the United States. Its natural habitat is rivers.

References

Somatogyrus Gastropods described in 1906 Taxonomy articles created by Polbot {{Hydrobiidae-stub