Winged Mapleleaf (Quadrula fragosa)
(Federally listed as Endangered)
Description: This is a medium-sized freshwater mussel that is approximately 4 inches in length with a yellowish-green to light brown color. Its shell is irregularly circular in shape with a well-developed “wing” and radiating ridges on its posterior end. The upper surface of the shell also has two rows of pustules or bumps. 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: Winged Mapleleaf mussels are found in small rivers and large streams with at least a moderate rate of flow. Within the river, these mussels embed themselves in areas of gravel or course sand substrate in the main channel.
Current and Historic Distribution: The Winged Mapleleaf was recently discovered in the Little River in southeastern Oklahoma. It also may occur in the Kiamichi and Boggy river systems. Historically, the Winged Mapleleaf was found in tributaries of the Mississippi River in at least ten states, but known populations currently are limited to small rivers in Oklahoma, Arkansas, Minnesota and Wisconsin.
Reasons for Decline: The causes for its decline are uncertain but may be related to past water pollution, pesticide use near waterways, or habitat loss that affected its fish host species. It is affected also by reservoir construction which fragments and isolates populations above and below dams.
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