No subspecies have been proposed in this species.
Status in Utah
Nine localities for this species in Utah are known (see Taylor et al. 1963); these represent 6 occurrences. These are from Cache and Summit counties in the extreme north-central part of the state and from Beaver County in south-central Utah.
The species potentially occurs throughout the Great Basin and Columbia Basin portions of the state--that is, roughly the northwestern one-third of Utah--and possibly the High Plateaus of central Utah and even the western parts of the Wasatch and Uinta mountains. However, the known localities in Utah suggest that the species may not actually occur within the Great Basin portion of the state but rather around the margins of the Great Basin, i.e., the shores of Pleistocene Lake Bonneville, which is a distributional pattern known for certain other animal species. Moreover, the restriction of this species to "the outflow of springs, or in clear mountain streams" (Taylor et al. 1963) suggests that few sites within the Great Basin in Utah would be suitable for it while many situations around the edges of the Great Basin would be ideal.
Taylor et al. (1963) reported 108 specimens of this species from Utah. "Most [of these] specimens were collected alive, but a few were recently dead" (Taylor et al. 1963).
Although actual threats to this species in Utah are not known, potential threats are great. 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). Impoundments and other alterations of flow such as channelization would also be serious threats since "it is never in large clear waters such as lakes or rivers" (Taylor et al. 1963). The population trend of this species in Utah is not known.
Inventory in proper habitat along the eastern edge of the Great Basin, especially
between Summit and Beaver counties is needed. The species should also be looked for in northwestern Box Elder County.
This species is extremely difficult to distinguish from some related species, especially Stagnicola caperatus, with which it is sympatric in Utah.
Habitats Utilized in Utah
Taylor et al. (1963) mentioned habitat information for 8 of the 9 Utah localities that they reported: "muddy ditch across a swampy pasture by the road", "spring ... tributary to Beaver Creek", "small stream", "half-dry spots by a ditch", "swampy pasture", "[s]wampy pasture along a ditch", "swampy pasture", "creek". Regarding the species throughout its range, these same authors stated: "S. montanensis is unique [within the family Lymnaeidae] in combining a pure-water habitat with a small or even seasonal water body." See Taylor et al. (1963, pp 267-271) for further discussion of the habitat specificity of this species.