Valvata Piscinalis - Shell Description

Shell Description

Valvata piscinalis has a somewhat pinched aperture and an attenuate spire. The spire height tends to increases in more eutrophic conditions. Shells of this species often exhibit 4–5 whorls and are white to beige with more orange to red pigmentation apically. The operculum shows spiral markings of around 10 turns, originating almost centrally.

The European valve snail can be confused with Valvata sincera, a native species in the Great Lakes; however, the United States species has a more spherical aperture, a wider umbilicus, a conical spire and more widely spaced and rough growth lines on the shell in comparison with the introduced species. In the Great Lakes, mature adult European valve snails are 5 mm high and 3–5 mm wide. In Europe, this snail has been found up to 7 mm high and 6.5 mm wide, but is usually smaller.

Dimensions of the shell are:

• Valvata piscinalis piscinalis - The width of the shell is 4–5 mm. The height of the shell is 3-4.5 mm.
• Valvata piscinalis antiqua - width: 4.5 mm. height: 6 mm.
• Valvata piscinalis geyeri - width: 2.5 mm. height: 3 mm.
• Valvata piscinalis discors - width: 3 mm. height: 3 mm.
• Valvata piscinalis alpestris - width: 6.3 mm. height: 5.5 mm.