Image Usage Information
Family: Valloniidae
Common name: Costate Vallonia
Discovery: Müller, 1774
Identification
Width: 2.5 mm
Height: 1 mm
Whorls: 3+
A heavy reflected lip and radial ridges characterize the shell of this animal. It is larger than V. parvula and has a slightly smaller umbilicus, though it is still quite open. The apex of the shell is low. The aperture is nearly circular with a wide lip, except at the point near the upper termination.
Ecology
Vallonia costata is a denizen of forest gaps and dry, open, rich habitats (Kerney & Cameron, 1979). In Maine this species appears in anthropogenic habitats, probably introduced (Nylander, 1936; Nekola, 2008), and Nekola suggests it is a European exotic, while Kerney & Cameron call it “holarctic.”
Taxonomy
A synonym for V. costata is Helix costata. Prior to work by Sterki in the 1890’s, early collections of V. costata were considered to be a variety of Vallonia pulchella (in Pilsbry, 1946-48).
Distribution
In eastern North America this species is generally distributed through the Midwest, Great Lakes, Mid-Atlantic and western New England, and eastern Canada (Hubricht, 1985). It has been found in various places throughout Virginia, but not as often along the southern edge of the state.
Conservation
NatureServe Global Rank: G5
NatureServe State Rank: S4
