Scaleshell (Leptodea leptodon)
(Federally listed as Endangered)
Description: The Scaleshell is an elongate, roughly oval-shaped freshwater mussel that grows to a length of approximately four inches. The shell is relatively thin, and yellowish-tan in color. Overall, this mussel has a relatively compressed and streamlined shape that may be an adaption to living in swift flowing waters. Like all freshwater mussels, it is a filter-feeder that filters fine organic material, suspended algae and microscopic organisms out of the flowing water around it.
Habitat: The Scaleshell is typically found in riffles within relatively swift moving water. It commonly lies buried a few inches below the bottom of the riffle in gravel or cobble substrate.
Current and Historic Distribution: In Oklahoma, populations of the Scaleshell are thought to remain only in the Kiamichi and Little rivers in the Ouachita Mountains in the southeastern part of the state. Historically, populations of the Scaleshell were known to exist in 13 states within the Mississippi River watershed, but currently they are known to occur only in Missouri, Arkansas and Oklahoma.
Reasons for Decline: The causes for their decline are uncertain but may be related to modification of river flow patterns by reservoir construction; in-stream gravel mining, past water pollution by pesticides, fertilizer and fine sediment; or reductions in the populations of their fish host species.