Plicate rocksnail

The plicate rocksnail is a pleurocerid snail with a shell that grows to about 20 mm (0.8 in) in length. Shells are subglobose with broadly rounded apertures. The body whorl may be ornamented with strong folds or plicae. Shell color is usually brown, occasionally green, and often with four equidistant color bands. The columella (central column or axis) is smooth, rounded, and typically pigmented in the upper half. The aperture is usually bluish-white, occasionally pink or white. Although morphologically similar to the basin's other three surviving rocksnail species, the plicate rocksnail is genetically distinct. == Distribution ==

The plicate rocksnail historically occurred in the Black Warrior River, the Little Warrior River, and the Tombigbee River. The latest survey information indicates that the snail has recently disappeared from the upstream two-thirds portion of that habitat and now appears to be restricted to an approximately 32 km (20 mi) reach in Jefferson County. == Reasons for the decline ==

The plicate rocksnail has disappeared from more than 90 percent of its historic range. The curtailment of habitat and range for this species (and a few other snail species) in the Mobile Basin's larger rivers – (Black Warrior River, the Little Warrior River, and the Tombigbee River for the plicate rocksnail) is primarily due to extensive construction of dams, and the subsequent inundation of the snail's shoal habitats by the impounded waters. This snail has disappeared from all portions of its historic habitats that have been impounded by dams. Such physical and chemical changes can affect feeding, respiration, and reproduction of these riffle and shoal snail species. == Ecology ==

Habitat Plicate rocksnails inhabit shallow gravel and cobble shoals in the flowing waters of rivers. ==References==