Pisidium casertanum, the pea cockle or pea clam, is a minute freshwater bivalve mollusc of the family Sphaeriidae.
Description
The shell is broad, sub-triangular or oval and is ornamented with sculpture of faint concentric striations. The umbos are slightly behind the middle. The Periostracum is silky, scarcely glossy. In colour it is whitish to grey-brown and often the shell is coated with reddish-brown deposits.
The shell is of similar shape to Sphaerium novaezelandiae but is smaller as an adult, more inflated, with a deeper hinge-plate, stronger teeth, and the ligament is not visible externally.
Length is up to 4.5 mm, height 3.7 mm, and thickness 2.3 mm.
Pisidium casertanum Presence in European countries
Distribution
It has a cosmopolitan distribution and is perhaps the world's widely distributed non-marine mollusc.
References
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^ Janus, Horst, 1965. ‘’The young specialist looks at land and freshwater molluscs’’, Burke, London
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^ Anderson, Roy (2005). "An annotated list of the non-marine molluscs of Britain and Ireland Journal of Conchology, 38 (6): 607–637" (PDF).
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^ 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.
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^ Juřičková L., Horsák M. & Beran L., 2001: Check-list of the molluscs (Mollusca) of the Czech Republic. Acta Soc. Zool. Bohem., 65: 25-40.
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^ Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, page 109, ISBN 3-923376-02-2
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^ "Anemoon> Flora en Fauna> Soorteninformatie". www.anemoon.org.
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^ Powell A W B, New Zealand Mollusca, William Collins Publishers Ltd, Auckland, New Zealand 1979 ISBN 0-00-216906-1
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^ 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
