Nimapuna tigersnail (Anguispira nimapuna new spp.)

Physical description

Taxonomic note: nimapuna tigersnail is in the family Discidae. This species appears to be an undescribed subspecies; they are distinctly like A. nimapuna from Idaho, but are smaller, with thinner shells and with weaker rib sculpturing.

Ecology and life history

In Idaho this species has been found between 1500 to 2550 feet in elevation at sites with an overstory that included western red-cedar and grand fir, with some alder, paper birch, Douglas-fir and/or ponderosa pine; often under wood or on bryophyte mats among dense ferns.

Land snails are hermaphroditic and exchange gametes with other conspecific individuals when conditions are favorable, typically in the spring, and then both will lay eggs in damp subsurface situations where the eggs will be relatively safe from predators and desiccation. Land snails do not tend their eggs or young. There is no larval stage and newborn snails look like miniature adults (the innermost part of the shell develops within the egg).

Snails need moisture, so where the habitat dries out, they will estivate in the summer, become active with fall rains, and hibernate when the season turns cold.

Land snails eat plants (living or dead), fungi, fruit, microorganisms, litter, wood, and dead animals.

During the summer, snails are found deep in talus accumulations which are adjacent to springs or streams and which serve as refuge sites from desiccation and protection from predators while the snails are immobile. These deep rock refugia also provide the important, environmentally stable sites needed to survive wildfire events and cold winter conditions.

Mollusks which inhabit talus habitats also utilize the surrounding forest areas during moist, cool conditions, ranging out from the refugia provided by the rocks to forage in the adjacent forest floor litter.

Geographic range

This yet-to-be described subspecies occurs at two locations on ridges on opposite sides of Lake Chelan, Chelan County, Washington. Outside of Washington, this species is known from less than 10 localities in the Clearwater, Lochsa, and Selway Rivers’ drainages in Idaho County, Idaho, and Wallowa County, Oregon.