Pisidium amnicum

Pisidium amnicum is a species of very small freshwater clam, sometimes known as the greater European peaclam or the River pea shell. It is an aquatic bivalve in the family Sphaeriidae.

Pisidium amnicum
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Sphaeriida
Family:	Sphaeriidae
Genus:	Pisidium
Species:	P. amnicum
Binomial name
Pisidium amnicum (O. F. Müller, 1774)

Description

Although only 9 mm (range 7–11 mm) in length, this species is considerably larger than most Pisidium species, and has a fairly thick, concentrically ridged shell. Its shell is solid, glossy, triangular-oval in shape, and has broad but not prominent umbos often coated with a dull ferruginous deposit. Its colour is grey-white to brown, often with a greenish cast.

Distribution

Its 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^[1][2]
• Slovakia^[2]
• Germany – highly endangered (Stark gefährdet)^[3]
• Nordic countries: Denmark, Finland, Iceland, Norway and Sweden (not in the Faroe Islands)^[4]
• Great Britain and Ireland^[5]

Ecology

In Europe, it requires clean water and high levels of calcium.