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Pinhead Spot - Paralaoma servilis
Other Names:
Punctum conspectum, Pseudohyalina conspecta, Helix conspecta, Zonites conspectus, Paralaoma caputspinulae
General Description
A very small shell, to about 2.4 mm diameter but more typically to 2.1 mm, 1.3 mm in height, flattened heliciform with a slightly elevated spire, with barely 4 whorls. Shell is translucent yellowish brown to darker brown, with a series of relatively tall cuticular riblets more or less regularly spaced and with very fine radial and spiral striae between. The aperture is crescent-shaped, obliquely wider than tall, lip not thickened, periphery rounded, umbilicus about 1/4 the shell diameter (Hendricks 2012, Burke 2013).
Diagnostic Characteristics
The spots are very small, yellowish brown shells (less than 3.0 mm diameter) with 4.0 to 4.25 whorls, which separates them from other species. Species of Pristiloma are more tightly coiled with more whorls, slightly larger in diameter with a narrow to absent umbilicus, and lack riblets. Punctum minutissimum is flatter in profile (lower conic) with a wider umbillicus than P. randolphi though similar in diameter, P. californicum is similar in shape to P. randolphi but larger with more solid riblets, Paralaoma caputspinulae is larger still (to > 2.0 mm diameter) with rather high cuticular riblets visible under magnification but with a flatter profile like P. californicum.
Species Range
Montana Range
Range Descriptions
Native
Range Comments
Widespread: Eurasisa to North Africa, the Americas and Australia; in North America from Alaska south to Mexico (Forsyth 2004, Burke 2013). In Montana, reported on both sides of the Continental Divide in five counties, including the extreme east and west; the extreme eastern record from Wibaux County may have been in drift material, other records are from mountainous areas. Elevation range is 823 to 2053 m (2700 to 6735 ft). Two live individuals found were in the Park County, Montana portion of Yellowstone National Park in 2009 apparently representing a new species for the Park (Hendricks 2012). Range and abundance in Montana poorly documented, current status needs investigation.
Observations in Montana Natural Heritage Program Database
Number of Observations: 11
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Relative Density
Recency
(Observations spanning multiple months or years are excluded from time charts)
Habitat
Near moisture, including streamside riparian zones; often disturbed sites. Tree canopy species include Douglas-fir. Found under woody debris and rocks, in leaf litter and duff (Hendricks 2012). Habitat in Montana is poorly understood.
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?- 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. 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.
- Squyer, H. 1894. List of shells from the vicinity of Mingusville, Montana. The Nautilus 8:63-65.
- Vanatta, E.G. 1914. Montana shells. Proceedings of the Academy of Natural Sciences of Philadelphia 66:367-371.
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