Virginia Land Snails
Photo(s): The domed shell of Discus patulus, by Larry Watrous ©.
Click photo(s) to enlarge.
Discus patulus (Deshayes, 1830)
Common name: Domed Disc
Width: 8.0 - 8.9 mm
Height: 3.3 – 4.0 mm
The shell of this disk is mostly flattened, with rounded, tight whorls, and a tiny basal lamella. It is notable for its very wide umbilicus and shallow-domed apex. It is usually light reddish-brown in color, with coarse but regular radial ribbing.
This species is sometimes found in deep layers of moist leaves, but more commonly on stumps and old logs in mature or late-successional forests. It is often patchy in distribution, with colonies around rotting woody debris. In Tennessee, its occurrence was correlated with increasing slopes, damper soils, and higher soil pH (Coney et al, 1982).
Synonyms for D. patulus are: Discus patulus angulatus, D. p. carinatus, Helix patula, H. perspectiva, Goniodiscus patula, Gonyodiscus perspectivus, Patula perspectiva, and Pyramidula (Gonyodiscus) perspectiva.
This snail is found very widely across most of the eastern US and southern Ontario, though it does not enter New England or Florida. Its range in Virginia covers the western, central, and south-western parts of the state.
NatureServe Global Rank: G5
NatureServe State Rank: S4
Greg Kimber, Ken Hotopp, Meegan Winslow 8/2012Range Map