Colligyrus convexus

Canary Duskysnail

Family: Amnicolidae · Class: Gastropoda · Order: Littorinimorpha

Conservation status: G2 S2

Colligyrus convexus (Canary Duskysnail) is a California animal in the Amnicolidae family.

The Canary Duskysnail is a small aquatic gastropod mollusk in the family Amnicolidae. This freshwater snail species is characterized by its compact, convex shell structure, which distinguishes it from other members of the genus Colligyrus. Adults typically measure less than 10 mm in shell length, with a rounded, dome-shaped profile that gives the species its distinctive appearance. The shell exhibits a yellowish to amber coloration, which likely contributes to its common name referencing canary yellow hues. The Canary Duskysnail has an extremely limited distribution, historically known from only one location in the Pacific Northwest region. According to federal documents, this species was previously referred to as Lyogyrus n. sp. 3 before receiving its current taxonomic designation (Federal Register 2011). The species occurs within the range covered by the Northwest Forest Plan, indicating its presence in federally managed forest lands in Oregon, Washington, or northern California. This species inhabits freshwater aquatic environments, specifically occupying streams, springs, or other flowing water bodies within forested watersheds. The Canary Duskysnail requires clean, well-oxygenated water with stable flow regimes and appropriate substrate conditions. Like other members of the Amnicolidae family, it likely depends on specific water chemistry parameters and substrate composition for successful reproduction and survival. The species appears to be endemic to spring-fed or groundwater-influenced aquatic systems that maintain consistent temperatures and water quality. As an aquatic gastropod, the Canary Duskysnail feeds on algae, detritus, and microscopic organic matter found on submerged surfaces. Reproduction likely follows typical gastropod patterns, with individuals laying eggs on hard substrates within the aquatic environment. The species probably has limited dispersal capabilities, contributing to its restricted range. Generation time and specific reproductive timing remain poorly documented, but most freshwater snails in this family have annual reproductive cycles tied to seasonal water temperature and flow patterns. The Canary Duskysnail currently holds a Global Conservation Status Rank of G2 (imperiled) and a State Conservation Status Rank of S2, indicating significant conservation concern due to its restricted range and small population size. The species was included in a 2011 petition to list 14 aquatic mollusks under the Endangered Species Act, with the U.S. Fish and Wildlife Service determining that the petition presented substantial information indicating that listing may be warranted (Federal Register 2011). Primary threats to this species include habitat modification from logging and grazing activities, which can alter watershed hydrology and water quality. The species' extremely limited distribution makes it particularly vulnerable to localized disturbances, pollution events, or changes in land management practices within its watershed. A 2007 environmental impact statement concluded that sufficient habitat exists to support stable populations within Northwest Forest Plan areas, though the species' single-location occurrence remains a significant conservation concern (Federal Register 2011).

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