Dark-bodied Glass-snail - Oxychilus draparnaudi
Helix lucida, Helicella draparnaudi
A medium sized shell, to 16 mm diameter and 8 mm in height but often smaller (Montana specimens averaged 10.6 mm diameter and reached 12.3 mm), flattened heliciform, smooth but with irregular incremental wrinkles and striae, about 5-6 whorls, the last whorl expanded at the aperture to more than twice the width of the previous whorl. Shell coloration is mottled pale brown above, paler below, glossy and translucent. Aperture is large, strongly oblique and crescent-shaped, without teeth (denticles); periphery rounded; umbilicus about 1/6 the shell diameter. Animal is bluish-black to dark bluish-gray on head and tentacles (Hendricks 2012, Burke 2013). Internal anatomy is described by Giusti and Manganelli (1997).
Oxychilus differ from other species by a combination of a generally smooth and translucent shell lacking a flared lip, no banding, an enlarged body whorl at the aperture less than half the diameter, a narrow umbilicus, a low to flattened spire. O. draparnaudi differs from O. alliarius by being larger (10-16 mm diameter compared to 8 mm), a shell that is wrinkled not smooth and glossy, and lacking a strong garlic odor when disturbed.
Western Europe and Mediterranean; introduced widely elsewhere including North America. In Montana, one report from East Missoula, Missoula County, west of the Continental Divide; elevation 1000 m (3280 ft). First reported for Montana in 2009. Range and abundance poorly understood in Montana; current status needs investigation. Probably occurs in many additional urban settings and valley bottoms. May be locally abundant; more than 30 individuals were found at the East Missoula site in early May (Hendricks 2012).
Observations in Montana Natural Heritage Program Database
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Frequents parks, gardens, and other modified habitats. Found in East Missoula under stacked lumber, rocks, woody debris, and brush, and in leaf litter. Habitat in Montana poorly understood (Hendricks 2012).
- 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.
- Giusti, F., and G. Manganelli. 1997. How to distinguish Oxychilus cellarius (Mueller, 1774) easily from Oxychilus draparnaudi (Beck, 1837) (Gastropoda, Pulmonata, Zonitidae). Basteria 61:43-56.
- 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
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- 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.
- Pilsbry, H.A. 1946. Land Mollusca of North America (north of Mexico), Volume II Part 1. Academy of Natural Sciences of Philadelphia Monograph Number 3 (2):1-520.
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