Royal Marstonia Snail

Pyrgulopsis ogmorhaphe

Description

The royal marstonia snail, Pyrgulopsis (=Marstonia) ogmorhaphe, is a small annual species, usually less than 0.25 in (6.4 mm) in length. It is distinguished from other closely related species by: 1) its relatively large size; 2) its large number of whorls (5.2 to 5.8); 3) its deeply incised, suture-producing, strongly shouldered whorls, which are almost flat above; 4) its complete aperture, which is broadly ovate in shape with a rounded posterior corner; 5) its outer lip, which is slightly arched forward in lateral profile; 6) its thin shell; 7) its conical terete shape; and 8) its enlarged bursa copulatrix with a completely exposed duct.

Behavior

This species eats diatoms and plant debris and has an annual life cycle.

Habitat

Royal marstonia snails are generally found in the diatomaceous "ooze" and on leaves and twigs in the quieter pools downstream from the spring source.

Distribution

The royal marstonia snail is known only from two spring runs in the Sequatchie River system in Marion County, Tennessee.

Because this species has an annual life cycle, the number of individuals varies from year to year, and the precise number of individuals is unknown. The royal snail has an extremely limited distribution and low numbers.

Threats

While no populations are known to have been lost, the general deterioration of the water quality that has resulted from siltation and other pollutants contributed by coal mining, poor land use practices, and waste discharges likely are impacting the species. This could result in serious, irreversible decline of the species. Additionally, both existing populations inhabit extremely limited areas, and they are very vulnerable to extirpation from accidental toxic chemical spills or vandalism. Other threats include road construction; agricultural, municipal, industrial, and mining runoff, both direct and from subsurface flows; cattle grazing; vandalism; and pollution from trash thrown into the spring. Also, timber harvesting for wood chip mills proposed for southeastern Tennessee and northeastern Alabama could impact this species.

Because this species is very rare, with populations restricted to extremely short stream reaches, unregulated taking for any purpose could threaten its continued existence.

Conservation and Recovery

The U. S. Fish and Wildlife Service notified federal agencies that might have had programs affecting this species. No specific proposed federal actions were identified that would likely affect the species. Federal activities that could have an impact on the species include, but are not limited to, the carrying out or the issuance of permits for reservoir construction, stream alteration, wastewater facility development, pesticide registration, and road and bridge construction.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30334
(404) 679-4000
http://southeast.fws.gov/

Ecological Services Field Office
446 Neal Street
Cookeville, TN 38501
Telephone: (615) 528-6481
Fax: (615) 528-7075

Reference

U. S. Fish and Wildlife Service. 15 April 1994. "Endangered and Threatened Wildlife and Plants: Determination of Endangered Status for the Royal Snail and Anthony's Riversnail." Federal Register, pp. 17994-17998.