Helicussus

Helicussus is a genus of small, arboreal gastropod mollusks belonging to the family Achatinellidae. These snails are native to the Hawaiian Islands and are characterized by their dextral, or right-handed, coiling shells. The shells are typically elongated and ovate, with a pointed apex. The aperture is usually narrow and elongated. The coloration of Helicussus shells can vary, often featuring shades of brown, yellow, or white, sometimes with darker bands or streaks.

The species within the Helicussus genus are primarily found in moist, native forest habitats, often on the leaves and branches of native Hawaiian trees and shrubs. They are herbivores, feeding on algae, lichens, and decaying plant matter. Reproduction in Helicussus, like other achatinellids, involves internal fertilization and the laying of a small clutch of eggs.

Many species of Helicussus are critically endangered or have gone extinct. The primary threats to their survival include habitat loss due to deforestation and the introduction of invasive species, such as predatory ants and rats, which prey on the snails and their eggs. Conservation efforts are underway for some species, focusing on habitat restoration and captive breeding programs, though the challenges remain significant for this vulnerable group of endemic Hawaiian snails.