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Genus Pisidium Pfeiffer, 1821

Subgenus Euglesa Leach in Jenyns, 1832

Diagnostic features

Shell small, short oval or quadrangular, moderately convex. Surface irregularly striated. Pores moderately dense. Hinge plate relatively narrow. Cardinal teeth arched or bent. Ligament enclosed. Presiphonal mantle suture elongated. Inner radial mantle muscles form five to seven strong bundles. Outer demibranch small, strongly shifted posteriorly.


Class Bivalvia  

Subclass Heteroconchia

Superorder Heterodonta

Order Cardiida

Superfamily Sphaeroidea

Family Sphaeriidae

Subfamily: Pisidiinae

Genus Pisidium Pfeiffer, 1821

Subgenus Euglesa Jenyns, 1832

Type species: Euglesa henslowiana Jenyns, 1832 (= Pisidium personatum Malm, 1855) (also sometimes cited as Tellina pusilla Gmelin, 1791)

Original reference: Jenyns, L. (1832). A monograph on the British species of Cyclas and Pisidium. Transactions of the Cambridge Philosophical Society 4: 289–311.

Type locality: Near Cambridge, England.

Synonyms: Australpera Iredale, 1943; Glacipisum Iredale, 1943

State of taxonomy

We follow the latest revision of the group by Korniushin (2000).

Biology and ecology

In rock and gravel substrate, amongst weed, and in sand and mud. Most frequent in creeks and small rivers. In South Australia and Tasmania it also inhabits springs, peat bogs, lakes and lagoons.


Cosmopolitan. In Australia, the genus is found throughout much of south-eastern Australia, including Tasmania, as well as in Central Australia.


The nature of the evolutionary relationship of Pisidium (Euglesa) tasmanicum to the rest of this subgenus is uncertain.

Further reading

Beesley, P. L., Ross, G. J. B. & Wells, A., Eds. (1998). Mollusca: The Southern Synthesis. Parts A & B. Melbourne, CSIRO Publishing.

Korniushin, A. V. (2000). Review of the family Sphaeriidae (Mollusca: Bivalvia) of Australia, with the description of four new species. Records of the Australian Museum 52: 41-102.

Kuiper, J. G. J. (1983). The Sphaeriidae of Australia. Basteria 47: 3-52.

Lamprell, K. & Healy, J. (1998). Bivalves of Australia, volume 2. Leiden, Backhuys Publishers.

Ponder, W. F., Clark, S. A. & Dallwitz, M. J. (2000). Freshwater and estuarine molluscs: an interactive, illustrated key for New South Wales. Melbourne, CSIRO Publishing.

Smith, B. J. & Kershaw, R. C. (1979). Field guide to the non-marine Molluscs of South-eastern Australia. Canberra, A.N.U. Press.

Smith, B. J. & Kershaw, R. C. (1981). Tasmanian Land and Freshwater Molluscs. Hobart, University of Tasmania.