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Montana Field Guide

Montana Field Guides

Tapered Vertigo - Vertigo ventricosa
Other Names:  Vertigo ventricosa elatior, Vertigo gouldi lagganensis, Vertigo elatior

Native Species

Global Rank: G5
State Rank: SNR

Agency Status

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General Description
A small shell, about 1.2 mm diameter and 2.2 mm in height, subovate (pupiform) with a moderately long and distinctly tapered spire, nearly smooth with only very fine incremental striae, about 5 whorls. Shell coloration is glossy brown. Aperture subovate, with five teeth (denticles: parietal, columellar, subcolumellar, upper palatal, lower palatal), palatal callus slight or absent, sinulus more or less strongly indented, crest weak or absent, lip thin and flared (Hendricks 2012, Burke 2013).

Diagnostic Characteristics
Combination of size (height < 3.0 mm) and shape, presence of teeth in a subovate aperture, 4-5 whorls, and an indentation in palatal lip distinguish Vertigo from similar appearing shells. A sinulus strongly indented in the aperture with a weak or absent palatal callus combined with 5 teeth in aperture distinguishes this species from all others, including V. ovata.

Species Range
Montana Range


Range Comments
Eastern Canada and northeastern United States west to Alberta, British Columbia, and Montana. In Montana, reported west of the Continental Divide from two counties: Lake, Ravalli. Elevation range is 1219 to 1262 m (4000 to 4140 ft). Range and abundance and in Montana poorly documented; current status needs investigation. Apparently never locally abundant; four were reported at the Lake County site in early July (Hendricks 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 3

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density



(Observations spanning multiple months or years are excluded from time charts)

Not described for Montana (Hendricks 2012); moist sites in aspen and willow stands in Wyoming. Found under woody debris and leaf litter (Beetle 1989).

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Citation for data on this website:
Tapered Vertigo — Vertigo ventricosa.  Montana Field Guide.  .  Retrieved on , from