Description: Shell a regular, flat coil with a conspicuous keel near the mid line. Aperture is a broad oval with the keel roughly in the middle. Last whorl about ⅓ total shell width. Easily confused with P. planorbis in the typical form (var. dubia Hartmann) of northern counties. This is flatter on the lower side and the keel is less developed than in typical carinatus. Widespread in large water bodies. 12-15 mm.

World Distribution: Found across Europe from Spain to Scandinavia. Distribution type: European Wide-temperate range (63).

Irish Distribution: Essentially a hard water species and often found abundantly in larger water bodies such as the open water of canals, rivers and lakes. Widespread and common in the central plain and the Lough Neagh and Erne Basins but rarer towards west and north coasts.

Ecology:

• Common in larger lakes and rivers
• Not in very soft or acid waters, except locally, as in interdrumlin lake margins in Cos Down and Armagh

Key Identification Features:

• A medium-sized brown shell with conspicuous keel near the mid line
• Aperture broadly oval with the adjoining keel roughly in the middle
• Last whorl about ⅓ total shell width
• Varieties with flatter undersides and shallower keels can be confused with P. planorbis

Red list status:

• Least concern (lc).

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

iNaturalist: Planorbis carinatus at iNaturalist World Species Observations database.

GBIF data for Planorbis carinatus | Classification: Gastropoda, incertae sedis, Planorbidae, Planorbis

Thumbnails for genus Planorbis