Pisidium henslowanum explained

Pisidium henslowanum is a species of very small freshwater clam or pea clam, an aquatic bivalve mollusc in the family Sphaeriidae. It is commonly referred to as the Henslow peaclam.

Etymology

The specific name honours John Stevens Henslow.

Description

The shell is obliquely oval. It has prominent, narrow umbos well behind the middle and the umbos have oblique raised crests. The surface (periostracum) is silky with fine, even concentric striae. The colour is greyish, especially at the umbos. Widespread but local and uncommon. The size is 3.5-5mm.

Distribution

Its native distribution is Holarctic.

• Czech Republic – in Bohemia, in Moravia,^[1] least concern (LC)^[2]
• Slovakia^[1]
• Germany – (Arten der Vorwarnliste)^[3]
• Nordic countries: Denmark, Faroes, Finland, Norway and Sweden (not in Iceland)
• Great Britain and Ireland^[4]

External links

• Pisidium henslowanum at Animalbase taxonomy,short description, biology,status (threats), images
• Images at BOLD.

Notes and References

1. 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.
2. Beran, L. (2002) Vodní měkkýši České Republiky - rozšíření a jeho změny, stanoviště, šíření, ohrožení a ochrana, červený seznam. Aquatic molluscs of the Czech Republic - distribution and its changes, habitats, dispersal, threat and protection, Red List. - Sborník přírodovědného klubu v Uherském Hradišti, Supplementum 10, 258 pp.
3. Glöer P. & Meier-Brook C. (2003) Süsswassermollusken. DJN, pp. 134, page 109,
4. Roy Anderson,2005 An annotated list of the non-marine molluscs of Britain and Ireland Journal of Conchology, 38 (6): 607–637, (published 2005)http://www.conchsoc.org/sites/default/files/MolluscWorld/Anderson-2008.pdf.