Pisidium amnicum

Pisidium amnicum

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

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^[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.

References

^ Red List of the molluscs (Mollusca) of the Czech Republic http://mollusca.sav.sk/malacology/redlist.htm
^ ^a ^b (in Czech) Horsák M., Juřičková L., Beran L., Čejka T. & Dvořák L. (2010). "Komentovaný seznam měkkýšů zjištěných ve volné přírodě České a Slovenské republiky. [Annotated list of mollusc species recorded outdoors in the Czech and Slovak Republics]". Malacologica Bohemoslovaca, Suppl. 1: 1-37. PDF.
^ Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, page 109, ISBN 3-923376-02-2
^ Kuiper, J. G. J.; Økland, K. A.; Knudsen, J.; Koli, L.; von Proschwitz, T.; Valovirta, I. (1989), "Geographical distribution of the small mussels (Sphaeriidae) in North Europe (Denmark, Faroes, Finland, Iceland, Norway and Sweden)" (PDF), Annales Zoologici Fennici, 26 (2): 73–101
^ Roy Anderson, 2005 An annotated list of the non-marine molluscs of Britain and Ireland Journal of Conchology, 38 (6): 607–637, (published 2005) [1].