Pisidium amnicum is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of very small freshwater clam. It is sometimes known as the greater European peaclam, an aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 bivalve in the family Sphaeriidae.

Description

Although only 9 mm in length, this species is considerably larger than most Pisidium species, and has a fairly thick, concentrically ridged shell

Bivalve shell

A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two parts, two valves which are hinged together...

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Distribution

It's native distribution is Palearctic. The species has been introduced to northeastern North America.

• Czech Republic - endangered (EN), endangered in Bohemia (EN), critically endangered in Moravia
• Germany - high endangered (Stark gefährdet)