Pyrgulopsis ventricosa

Clear Lake Pyrg

Family: Hydrobiidae · Class: Gastropoda · Order: Littorinimorpha

Conservation status: G1 S1

The Clear Lake Pyrg (Pyrgulopsis ventricosa) is a small freshwater gastropod mollusk in the family Hydrobiidae. This species is endemic to California and represents one of numerous springsnail species in the western North American genus Pyrgulopsis, which are characterized by extremely localized distributions and small population sizes. The Clear Lake Pyrg is classified as G1 S1, indicating it is critically imperiled both globally and within California, with typically fewer than five occurrences or very few remaining individuals. Like other members of the genus Pyrgulopsis, the Clear Lake Pyrg likely measures only a few millimeters in length with a conical shell typical of springsnails. These aquatic gastropods typically possess transparent to light brown shells with multiple whorls, though specific morphological details for P. ventricosa have not been comprehensively documented in available literature. Based on the species name and genus characteristics, the Clear Lake Pyrg is presumably associated with the Clear Lake region of California, though its precise current distribution and historical range remain poorly documented. Pyrgulopsis species are typically restricted to single spring systems or very small geographic areas, making them extremely vulnerable to local disturbances. Members of the genus Pyrgulopsis inhabit freshwater spring environments, including spring pools, spring runs, and associated wetland habitats. These springsnails require consistent water temperatures and flow regimes that are characteristic of natural spring systems. Spring environments provide the stable conditions necessary for these specialized mollusks, including consistent water chemistry and temperature regulation. Springsnails in the genus Pyrgulopsis are typically grazers, feeding on algae, diatoms, and organic detritus in their aquatic environments. Reproduction involves direct development without a larval stage, with individuals depositing eggs on hard surfaces within the spring habitat. Population dynamics and specific ecological requirements for the Clear Lake Pyrg have not been well studied. The G1 S1 conservation ranking indicates the Clear Lake Pyrg faces extreme risk of extinction. Throughout the western United States, Pyrgulopsis species have experienced extensive habitat loss and degradation due to spring development, groundwater withdrawal, water diversions, pollution, and livestock impacts (Xerces Society 2019). Many springsnail species have suffered dramatic population declines or local extinctions as spring systems have been modified or destroyed. The highly localized nature of springsnail populations makes them particularly vulnerable to single disturbance events that could eliminate entire populations. Scientific documentation for this species remains extremely limited. Detailed studies of the Clear Lake Pyrg's distribution, population status, habitat requirements, and specific conservation needs are urgently needed to develop appropriate management strategies and assess its current conservation status.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.