common whorl snail

<em>Vertigo pygmaea</em>, commonly known as the common whorl snail, is a minute land snail in the family Vertiginidae, listed as Near Threatened on the IUCN Red List, reflecting documented population declines attributable to habitat loss, agricultural intensification, and wetland drainage across its European and North American range. The species occurs across much of Europe and parts of the United States, typically inhabiting short-sward calcareous grasslands, chalk and limestone downlands, damp meadows, and the bases of grassy slopes where the vegetation structure is open and low-growing. <em>Vertigo pygmaea</em> is among the smallest terrestrial mollusks, with a shell typically measuring only 1.5–2 mm in height — a feature shared by all members of the genus Vertigo. Despite its tiny size, the shell is complex, with multiple internal tooth-like lamellae visible within the aperture that are used in species identification. The species typically feeds on decaying plant material, algae, and fungi associated with soil and leaf litter microhabitats. It requires specific microhabitat conditions including moderate soil moisture and an abundance of calcium for shell formation. Biological traits including average lifespan, precise shell dimensions, and mass remain poorly documented in standardized databases. Conservation efforts for <em>Vertigo pygmaea</em> typically focus on maintaining and restoring calcareous grassland habitats through appropriate grazing management regimes.