Land Snails

Photo(s): Mesomphix subplanus © Bill Frank, shell © Dan Dourson.

Click photo(s) to enlarge.

Mesomphix subplanus (A. Binney, 1842)

Family: Zonitidae
Common name: Flat Button

Identification
Width: 16.0–22.3 mm
Height: 6.0–10.6 mm
Whorls: 5.5+

The shell of Mesomphix subplanus is similar in overall plan to many other Mesomphix, but looks as if it has been squeezed in a press. The umbilicus is tiny and is only somewhat indented from the base, which is quite flat, and the apex is also flattened. The shell is thin, and the lip of the aperture is simple and thin. The glossy shell may vary in color, being olive or brown, and it is has radial striations.

Ecology
This species is found at higher altitudes, 2,000 feet or above, in moist leaf litter and around logs (Hubricht, 1985).

Taxonomy
Synonyms for M. subplanus are: Helix sub-plana, Mesomphix subplana, M. subplanus planus, Omphalina subplana, and Zonites subplanus.

Distribution
Mesomphix subplanus has a range similar to that of M. rugeli, though even more limited. It is found mostly along the North Carolina/Tennessee line. It appears in scattered western Virginia counties.

Conservation
NatureServe Global Rank: G3/G4, Vulnerable to Apparently Secure
NatureServe State Rank: Virginia, S2, Imperiled
Virginia’s wildlife action plan: Tier III

 

Greg Kimber, Ken Hotopp 11/2012

Range Map (click to enlarge)