Land Snails

Photo(s): Views of a Striatura exigua shell, © Jeff Nekola. A close look at the apex shows the unique ridge and spiral lirae pattern.

Click photo(s) to enlarge.

Striatura exigua (Stimpson, 1850)

Family: Gastrodontidae
Common name: Ribbed Striate

Identification
Width: 2.3 mm
Height: 1.25 mm
Whorls: 3+

The shell of Striatura exigua is uniquely sculptured, with fine spiral lirae creating a crosshatch pattern interrupted by taller transverse ridges. No other tiny shell bears this one-of-a-kind microsculpture. The umbilicus is open and wider than the aperture, which is rounded and simple.

Ecology
Striatura exigua is a common snail of mesic forest habitats in the Northeast. It was the second most common snail at a dozen upland study sites in the Adirondack Mountains (Beier et al, 2012), and it occurred at all but the wettest and richest sites in northern Maine (Nekola, 2008). In the central Appalachian Mountains, where it lives in damp leaf litter and swampy woods (Hubricht, 1985; LeGrand et al, 2006), it becomes somewhat less frequent (e.g. Hotopp, 2002).

Taxonomy
Synonyms for S. exigua include: Helix annulata, H. exigua, Pseudohyalina exigua, Striatura exigua, and Zonites exiguus.

Distribution
This animal’s range includes much of the Midwestern and eastern states and Canadian Provinces. In Virginia it is found in the western part of the state.

NatureServe Global Rank: G5
NatureServe State Rank: S2
Virginia’s wildlife action plan: Tier IV

 

Ken Hotopp, Meegan Winslow 11/2012 Range Map (click to enlarge)