The shale pebblesnail (''Somatogyrus pennsylvanicus'') is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of very small

freshwater snail Freshwater snails are gastropod mollusks which live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs ...

with an operculum. It is an aquatic gastropod mollusc in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Lithoglyphidae Lithoglyphidae is a family of small freshwater snails with gills and an operculum, aquatic gastropod mollusks. This family is in the superfamily Truncatelloidea and in the clade Littorinimorpha (according to the taxonomy of the Gastropoda by ...

Distribution

This species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found els ...

river A river is a natural flowing watercourse, usually 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 ...

s in

Pennsylvania Pennsylvania (; (Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, Ma ...

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the East Coast of the United States, Atlantic Coast and the Appalachian Mountains. The geography an ...

and

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the ...

in the United States.

References

Somatogyrus Endemic molluscs of the United States Gastropods described in 1904 Taxobox binomials not recognized by IUCN {{Lithoglyphidae-stub