The Owyhee upland pyrg is tiny, gill-breathing, operculate, aquatic snail. It can be distinguished by its disjunct inner shell lip, longer and narrower penial filament, more distally positioned ventral gland of its penis, and mitochondrial DNA sequences. It is a small to medium-sized species having an ovate to narrow conic shell with medium to highly convex whorls.
The Owyhee upland pyrg only occurs in five small, disconnected areas in tributaries of the Snake River. P. owyheensis lives in spring sources and stream outflows, including both cold and thermal springs. It is found on a variety of hard substrates, including silt-gravel substrate with abundant grasses. Reported collection depths are from 0 to 7.6 cm (0 to 3 in.), at elevations of 1090 to 1095 m (3580 to 3590 ft.).
Limiting factors
Springsnails require high quality habitats with little disturbance. Disturbances to springs that negatively impact Pyrgulopsis species include livestock grazing (due to trampling of the snail and its habitat from livestock and pollution from their excrement), recreational activities (such as bathing) which may lead to pollution and accidental crushing of the snail, introduction of invasive species, and changes to the availability of underground freshwater storage.
Data gaps
Collect life history information. Obtain current population size and trend data. Assess distribution and determine range. Assess the tolerance range of this species to environmental change.
Conservation actions
Monitor existing populations and survey suitable habitat for new populations. Manage new and known sites and their associated watersheds to reduce the impacts of recreational activity, livestock grazing, water diversions, invasive species, and other activities that may adversely affect water quality. Maintain water quality, substrate conditions, and riparian areas at occupied sites.
Key reference or plan
Petition to Protect the Owyhee upland pyrg (Pyrgulopsis owyheensis) under the Endangered Species Act. 2024. The Center for Biological Diversity. 16 pp.
Blackburn, M. and S. Foltz Jordan. 2020. Interagency Special Status/Sensitive Species Program (ISSSSP) Species Fact Sheet: Pyrgulopsis owyheensis. USDA Forest Service Region 6 and USDI Bureau of Land Management Oregon State Office. 17 pp.
