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Montana Field Guide

Montana Field Guides

Lambda Snaggletooth - Gastrocopta holzingeri
Other Names:  Pupa holzingeri

Native Species

Global Rank: G5
State Rank: SNR

Agency Status

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General Description
A very small shell, to 0.8 mm diameter and 1.9 mm in height, subcylindrical (pupiform) and tapering, about 5 whorls. Shell coloration is translucent white. Aperture oval, with six teeth (denticles: forked parietal, columellar, subcolumellar, lower palatal, upper palatal, suprapalatal), the forked parietal tooth in the shape of the Greek letter lambda (upside down "y") with one end attached to the aperture lip, columellar tooth curves downward within the aperture, palatal callus present, sinulus absent, crest present and oblique, lip thin and flared (Hendricks 2012, Burke 2013).

The subspecies in Montana would be Gastrocopta holzingeri holzingeri

Diagnostic Characteristics
Shape (pupiform) and color (transparent whitish), with teeth in the aperture distinguish Gastrocopta from similar sized and shaped shells (Pupilla, Vertigo, Columella). G. armifera is the largest (height > 3.5 mm, diameter > 2.0 mm) with 6 teeth in aperture. Both G. holzingeri and G. pentadon are about 2.0 mm in height and 1.0 mm in diameter. G. holzingeri has a parietal tooth forked and shaped like the Greek letter lambda and a columellar tooth curving downward (basally) within aperture; the parietal tooth of G. pentodon is not lambda-shaped and the columellar tooth does not curve downward within the aperture.

Species Range
Montana Range


Range Comments
Ontario and western New York west to Alberta and Montana, south to Kansas and New Mexico. In Montana, reported east of the Continental Divide from two counties: Lewis and Clark, Wibaux. Elevation range is 823 to 1372 m (2700 to 4500 ft). Range and abundance in Montana are poorly understood; current status needs investigation (Hendricks 2012).

Observations in Montana Natural Heritage Program Database
Number of Observations: 1

(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). Wooded slopes under moist leaf litter in British Columbia (Forsyth 2004).

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Citation for data on this website:
Lambda Snaggletooth — Gastrocopta holzingeri.  Montana Field Guide.  .  Retrieved on , from