Land Snails

Photo(s): The short hairs upon Stenotrema hirsutum pick up debris, image by Kevin Ripka via Wikimedia Commons. The bottom view of its shell, © Bill Frank, shows the base of the “fulcrum” lamella within, to the left side of the aperture.

Click photo(s) to enlarge.

Stenotrema hirsutum (Say, 1817)

Family: Polygyridae
Common name: Hairy Slitmouth

Identification
Width: 6.5-9.5 mm
Height: 4-6 mm
Whorls: 5+

This species has a small rounded shell, covered in short hairs and having a narrow aperture. Stenotrema hirsutum is generally smaller and rounder than its relative S. barbatum. Its hairs are finer and the aperture a tiny bit wider. In side view the parietal lamella of S. hirsutum is not pronounced. The short hairs of its shell usually trap debris and spider webs. In the field this species has the appearance of a basswood seed.

Ecology
Stenotrema hirsutum is a shy animal that favors complex ground structure for its habitat. It may be found in leaf litter, under logs and sometimes among vine-covered rock talus. It is normally quite patchy in its distribution, perhaps owing to the distribution of structure. It appears to prefer somewhat richer soils, and in Michigan appeared to be strongly calciphilic (Lee, 1952). There is some discrepancy about its habitat preferences in the literature, with Hubricht (1985) stating that it prefers drier habitats and Lee (1952) that it prefers damp.

Taxonomy
Synonyms for S. hirsutum include: Helix hirsuta, H. porcina, Polygyra hirsuta, P. h. nana, and P. h. yarmouthensis.

Distribution
Stenotrema hirsutum is a snail of Appalachian Mountain forests from Georgia, north to southern Michigan and northeast into the Berkshires of Massachusetts. It may be found across most of Virginia, but is absent from the southeast Atlantic Coast.

NatureServe Global Rank: G5
NatureServe State Rank: S4

 

Ken Hotopp, Meegan Winslow 11/2012

Range Map (click to enlarge)