Land Snails

Photo: Discus rotundatus. Image © Roy Anderson




Illustrations © Kathy Schmidt from her series "Land Snails of New York State."

Click photo to enlarge.

Discus rotundatus (Müller, 1774) (non-native)

Family: Discidae
Common name: Rotund Disk

Identification
Width: 5.5-7.0 mm
Height: 2.5-3.0 mm
Whorls: 5.5-6.0

The shell of this species is brown with reddish radial stripes or spots. The aperture is simple, the umbilicus open, and the transverse ribs somewhat coarse as is typical of many disk snails. The shell periphery is mildly keeled. The animal is blue-gray, darker above.

Ecology
Discus rotundatus lives in damp habitats – in woods, among herbaceous vegetation, under leaf litter and rocks, and in trash piles (Kerney and Cameron, 1979). In Poland, D. rotundatus reaches maturity in its second or third year and lives 2.5-3.5 years (Kuźnik-Kowalska, 1999). Up to 11 eggs are laid in a clutch, with peak egg-laying season in July and August (Kuźnik-Kowalska, 1999).

Taxonomy
Synonyms are Helix rotundata, Pyramidula rotundata (Pilsbry, 1948).

Distribution
Discus rotundatus is a central and western European native that has been spread to coastal and urban habitats in North America.

Conservation
NatureServe Global Rank: G5, Secure.

 

Ken Hotopp, 9/2017

Range Map (click to enlarge)