Raleigh Ecological Services Field Office
Conserving the Nature of America

Noonday snail (Peters clarkia nantahala)

Noonday snail. Credit: USFWS

Noonday snail. Credit: USFWS

Federal Status: Threatened, July 3, 1978

Description: The noonday globe snail is a moderately sized (0.75 inch wide by 0.5 inch high; (1.9 centimeter wide by 1.3 centimeter high)) land snail. Its shell is shiny and reddish in color. The surface of the shell is sculptured with rather course lines. The area around the shell opening (aperture) is white, and a long curved "tooth" is located on the inside portion of the aperture. The animal’s body is black.

Because this snail is so rare and restricted in distribution, very little is known of its biology. The species' reproductive behavior is unknown, and its food habits are also a mystery. However, other related species in the genus Petera feed on the subsurface hair-like structure (mycelia) of fungi. The species appears to be most active during wet weather, when it’s frequently found out on the surface of vegetation rather than under the leaf litter on the forest floor.

Habitat: The snail is found in the Nantahala Gorge, on wet cliffs that are intersected by many small streams and waterfalls. The forest is mature, with many large trees and a diverse plant community. The forest floor has a thick, rich humus layer, and the area has many exposed calcareous (rich in calcium) rocks. Calcium, which is generally scarce in other cliffs in the area, is vital to snails because it is a major component of their shells.

map of Noonday snail distribution in North Carolina

Map of Noonday snail distribution in North Carolina.

Distribution: The noonday globe snail is known from only about two miles (3.2 kilometers) of high cliffs within the Nantahala Gorge in Western North Carolina.

Threats: The noonday globe was likely never widely distributed. Steep wet slopes with calcareous rocks are rare in Western North Carolina. However the species was likely somewhat more widely distributed within the gorge before the gorge was altered for a railroad and highway. The associated loss of the forest canopy allowed more sunlight to penetrate the gorge and likely dried the lower slope of the gorge. This habitat alteration also allowed such non-native plants as kudzu and Japanese honeysuckle to invade some roadside areas, changing the area’s natural plant and animal community.

References:

LeGrand, Jr., H.E., J.T. Finnegan, S.E. McRae, S.P. Hall. 2010. Natural Heritage Program List of the Rare Animal Species of North Carolina. N.C. Natural Heritage Program, Raleigh, NC.

U.S. Fish and Wildlife Service. 1984. Recovery Plan for the Noonday Snail (Peters clarkia nantahala). U.S. Fish and Wildlife Service, Atlanta, GA. 30 pp.

For More Information on Noonday snail...

Species Contact:

John Fridell, Fish and Wildlife Biologist, 828-258-3939 ext. 225

Species profile revised on October 4, 2011.

Last Updated: November 1, 2012