Description: A small, fragile bivalve with an oval to quadrangular, pearly grey shell. Umbos slightly in front of middle, directed forwards and capped by the juvenile shell. Uncommon in poor or temporary habitats. 8-11 mm.

World Distribution: Widespread across the north temperate zone. Distribution type: Circumpolar Temperate (76).

Irish Distribution: Thinly distributed but locally common in the north-east, east and the southern half.

Ecology:

• A species mainly of small, temporary or 'poor' habitats where few other species are present
• Occasional in sand-pits and areas subject to seasonal flooding around large lakes

Key Identification Features:

• A small, fragile, pearly grey to white bivalve shell
• Umbos slightly in front of middle, directed forwards and capped by the juvenile shell
• Posterior end broad and roughly truncated
• Surface ornamented with fine even concentric striation and fairly glossy

Red list status:

• Vulnerable (VU).

Distribution Map from NBN: Sphaerium lacustre at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Sphaerium lacustre at iNaturalist World Species Observations database.

GBIF data for Musculium lacustre | Classification: Bivalvia, Sphaeriida, Sphaeriidae, Musculium

Thumbnails for genus Musculium