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Crestless Column - Pupilla hebes
Other Names:
Pupa hebes, Pupilla muscorum idahoensis
General Description
A small shell, 1.5 mm diameter and 3.5 mm in height, subcylindrical (pupiform), surface with fine incremental and wrinkle-like striae, with 6 to 7 whorls. Shell coloration is brownish. Aperture rounded to ovate, without teeth (denticles) but with a columellar baffle behind the columella, sometimes with a slight bulge in place of a parietal tooth, crest low to prominent and the same color as the rest of the shell, sinulus absent, lip expanded (flared) but not thickened (callus absent). Occurs in some locations in both dextral (coiling to the right from the aperture) and sinistral (coiling to the left from the aperture) forms (Hendricks 2012, Burke 2013).
Diagnostic Characteristics
Pupilla are brownish shells with teeth or internal baffles, and possess an external crest behind the aperture (unlike Columella). The palatal lip is not indented, mature shells have 6-9 wholrls, the combination of which separates Pupilla from similar shaped and sized pupiform shells (Verigo). Absence of teeth in aperture distinguish Pupilla muscorum and P. hebes from P. syngenes and P. blandi. P. hebes similar to P. muscorum but lacks the light colored crest behind the aperture lip and a palatal callus present in the latter species.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
In North America from Alaska south to Mexico and east to Idaho and Wyoming. In Montana, reported east of the Continental Divide in Stillwater County; elevation 1731 m (5780 ft). Nine shells were reported at a Stillwater County site in late August. Range and abundance in Montana are poorly understood; current status needs investigation (Hendricks 2012).
Observations in Montana Natural Heritage Program Database
Number of Observations: 2
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Map Help and Descriptions
Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Not described for Montana; wooded sites elsewhere. Canopy includes aspen, elsewhere in rocky sites under conifers and cottonwoods. Found in leaf litter, among grasses, and under rocks in shrubby sites (Hendricks 2012).
Stewardship Responsibility
References
- Literature Cited AboveLegend:
View Online Publication
Burke, T. E. 2013. Land snails and slugs of the Pacific Northwest. Corvallis, OR: Oregon State University Press. 344 p.- Hendricks, P. 2012. A Guide to the Land Snails and Slugs of Montana. A report to the U.S. Forest Service - Region 1. Montana Natural Heritage Program, Helena, MT. vii + 187 pp. plus appendices.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?- Beetle, D. E. 1961. Mollusca of the Big Horn Mountains. The Nautilus 74:95-102.
- Beetle, D.E. 1989. Checklist of recent Mollusca of Wyoming, U.S.A. The Great Basin Naturalist 49(4):637-645.
- Forsyth, R.G. 2004. Land snails of British Columbia. Royal British Columbia Museum: Victoria, British Columbia, Canada. 188 pp.
- Frest, T.J. and E.J. Johannes. 2001. An annotated checklist of Idaho land and freshwater mollusks. Journal of the Idaho Academy of Science 36(2):1-51.
- Harris, S.A. 1978. Vertical zonation of land snails in the Iraqi slopes of the Persian Mountains and in the Rocky Mountains of Alberta, Canada. Arctic and Alpine Research 10:457-463.
- Nekola, J.C. and B.F. Coles. 2010. Pupillid land snails of eastern North America. American Malacological Bulletin, 28(2):29-57
- Pilsbry, H.A. 1948. Land Mollusca of North America (north of Mexico), Volume II Part 2. The Academy of Natural Sciences of Philadelphia Monograph Number 2(2): 521-1113.
- Web Search Engines for Articles on "Crestless Column"
- Additional Sources of Information Related to "Snails / Slugs"
