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Virginia Land Snails

Helicodiscus parallelus (Say, 1817)

Family: Helicodiscidae Common name: Compound Coil

Identification Width: 3-4 mm Height: 1.25-1.75 mm Whorls: 4+ Photo(s): Views of a Helicodiscus parallelus shell, by Larry Watrous ©. The flattened shell of Helicodiscus parallelus bears parallel spiral lirae that increase in strength on the later Note that the spire is just slightly raised whorls. These lines cause the shell to look like a small tire. The narrow, steep-sided aperture is partly above the plane of the later whorls. obstructed by pairs of cone-shaped teeth, arranged radially. One to three pairs of these teeth may be present, one in the mouth of the aperture itself, and the other pair(s) located further inside the final whorl. The umbilicus Click photo(s) to enlarge. is relatively deep for its genus; the spire is low, slightly raised above the body whorl, but not quite as low as that of H. shimeki which is not at all raised.

Ecology This animal is a blind snail, like others in its family, and lives in damp, decaying wood and leaf matter. It may be found in forested floodplains or uplands, rocky woods, but also open habitats such as grasslands and roadsides. In Maine it was found in habitats from dry forest to wet sedge meadows (Nekola, 2008).

Taxonomy Synonyms for H. parallelus include Helicodiscus lineatus, H. theresa, Helix lineate, and Planorbis parallellus.

Distribution Helicodiscus parallelus is found throughout the eastern and Midwestern United States and Canadian provinces, from Maine to Florida and Minnesota to Texas. It is found throughout Virginia.

NatureServe Global Rank: G5 NatureServe State Rank: S5

Ken Hotopp, Meegan Winslow 11/2012

Range Map