Montana Field Guide

Stagnicola montanensis is a species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusk in the family Lymnaeidae, the pond snails.

The shell of this aquatic snail is dextrally spiraled and globose-conical in general shape. The columella is lightly twisted, and the shell is brown; body is dark (see photo)(Frest 1999).

Sedentary.

This species occurs in small cold water rivers or spring-fed tributaries to larger river systems. Aquatic vegetation and algae are generally absent from occupied sites. This species is not found in areas with mud, sand, or bedrock (Frest 1999).

Most Lymnaeidae snails are scrapers of algae and other plant materials.

This species is hermaphroditic. No information is available regarding the timing of reproduction or other aspects of reproductive ecology.

This species is limited in distribution, most states within the range do not have comprehensive distribution or survey information. This species is believed to be extirpated from Utah Little Bear River drainage. Surveys are needed to ascertain the current distribution and population numbers, and DNA analysis should be done for taxonomic certainty of this species.

Though threats have not been assessed specifically for MT, the small drainages and spring outflows preferred by this species are particularly vulnerable to grazing (Frest and Johannes 1995). Habitat loss is the primary threat to this species. Conversion of cold springs for stock and domestic usage and grazing are among the greatest threats (Frest 1999). Since "[i]t is a pure-water snail" (Taylor et al. 1963), any degradation of water quality where it occurs, such as erosional runoff from road or other construction producing turbidity or siltation, would be a threat since "it is never found in ... muddy water bodies" (Taylor et al. 1963).