Magazine Mountain Shagreen
Magazine Mountain Shagreen
|Listed||April 17, 1989|
|Family||Polygyridae (Land Snail)|
|Description||Medium-sized, dusky brown or buff colored shell.|
|Habitat||Cool, moist, rocky crevices in rock slide rubble.|
|Threats||Limited distribution, recreational development, military exercises.|
Also known as the Magazine Mountain middle-toothed snail, the Magazine Mountain shagreen, Mesodon magazinensis, is a dusky brown or buff-colored medium-sized land snail, 0.5 in (13 mm) wide and 0.3 in (7 mm) high. The shell surface is roughened by half-moon shaped scales. The outer lip of the aperture has a small triangular tooth, while the inner side has a single blade-like tooth. It is similar in appearance to the more common M. infectus.
This mountain shagreen is active above the surface on cool, damp or wet days and retreats into the rock crevices as the weather warms. During July and August it never surfaces.
Its blade-like tooth is suitable for eating plant material.
This snail has been collected from rock slide rubble at the base of a north-facing rocky escarpment. It prefers cool, moist conditions and burrows far back into crevices in the cliffs, during the hottest part of summer. Habitat elevation ranges from 2,000-2,600 ft (600-790 m).
This species is known only from a single location on Magazine Mountain in Logan County, Arkansas. Magazine Mountain is relatively separate from other mountains in the region and is considered an "island" ecosystem—one that supports a diversity of endemic species within a narrowly defined range.
The shagreen's known range is included within the Ozark National Forest and is classified as a Special Interest Area. Magazine Mountain was recently proposed as a candidate for designation as a Research Natural Area.
Because of this snail's extremely limited range, it is vulnerable to any land use change or other activity that might disrupt the habitat's fragile ecological balance. In 1989 the Arkansas Department of Parks and Tourism applied for a special use permit from the Forest Service to develop a state park on Magazine Mountain. The U. S. Fish and Wildlife Service (FWS) has expressed the opinion that construction of access roads, buildings, pipelines, and trails would adversely affect the snail if these activities disrupted rock slide rubble on the north slope. The FWS, the Forest Service, and the state are currently negotiating to determine the feasibility of the proposed state park.
Conservation and Recovery
U. S. Army training exercises planned for the vicinity of Magazine Mountain will be permitted by the FWS if troop, vehicle, and artillery movements do not disturb the north slope of the mountain. Under provisions of the Endangered Species Act, the Army is required to consult with the FWS before any exercises are undertaken. Such a consultation might allow exercises to be held, so long as conditions to protect the snail's habitat are met.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
Caldwell, R. S. 1986. "Status of Mesodon magazinensis, the Magazine Mountain Middle-Toothed Snail." Report for Grant No. 84-1. Arkanasas Nongame Species Preservation Program, Little Rock.
Hubricht, L. 1972. "The Land Snails of Arkansas."Sterkiana 46:15-16.
U.S. Fish and Wildlife Service. 1989. "Determination of the Magazine Mountain Shagreen, Mesodon magazinensis, as an Endangered Species." Federal Register 54(72): 15286-15287.