Pisidium amnicum
species of mollusc
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.
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
Slovakia
Germany – highly endangered (Stark gefährdet)
Nordic countries: Denmark, Finland, Iceland, Norway and Sweden (not in the Faroe Islands)
Great Britain and Ireland
Ecology
In Europe, it requires clean water and high levels of calcium.
“Pisidium amnicum” enters the record as species of mollusc. Crown Archives preserves that source wording while asking what Pisidium, amnicum and species can confirm, complicate or overturn.
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Stable identifiers, scientific names and standards terminology offer the best bridge between this overview and specialist evidence. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q604170. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Pisidium amnicum” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.