Polygyra

Polygyra is a genus of terrestrial pulmonate gastropods in the family Polygyridae. The genus was first described in the early 19th century by the American malacologist Thomas Say. Species within Polygyra are small to medium-sized land snails that possess helically coiled, glossy shells ranging from 10 to 25 mm in diameter. The shells typically have 4 to 5 whorls and a flattened spire, with a rounded aperture and a callus ridge along the lip.

Polygyra species are widely distributed across eastern and central North America, with occurrences reported in the United States and southern Canada. They inhabit moist deciduous and mixed forests, often found beneath leaf litter, rotting logs, or damp bark. The snails are detritivores, feeding on decaying plant matter and fungal spores, and play a role in nutrient recycling within forest ecosystems.

Reproduction in Polygyra is hermaphroditic; individual snails possess both male and female reproductive organs and are capable of self-fertilization, although outcrossing is common. Eggs are laid in moist microhabitats, and juveniles emerge as miniature versions of adults after a brief planktonic stage. Lifespan in the wild typically ranges from 2 to 5 years, depending on environmental conditions.

The genus is not generally considered endangered, and most species maintain stable populations; however, some localized populations are threatened by habitat loss and fragmentation. Conservation efforts focus on preserving forested wetlands and maintaining the integrity of leaf litter layers. Recent molecular studies have refined the phylogenetic relationships within Polygyridae, confirming Polygyra as a distinct lineage within the eastern North American fauna.