Ouachita Rock Pocketbook (Arkansia wheeleri)
(Federally listed as Endangered)
Description: This is a medium-sized freshwater mussel with a dark brown to nearly black, and slightly oval-shaped shell. It is a filter-feeder that filters particles of decaying vegetation and microscopic animals and algae from the water that flows around it.
Habitat: The Ouachita Rock Pocketbook embeds itself in coarse sediment and gravel at the bottom of the river channel in the Kiamichi and Little rivers in southeastern Oklahoma.
Current and Historic Distribution: The Ouachita Rock Pocketbook is a very rare mussel and makes up a fraction of one percent of the mussel community of the rivers in which it occurs. Currently, the last remaining populations exist in the Kiamichi River in Oklahoma, the Little River in southeastern Oklahoma and southwestern Arkansas, and the Ouachita River in Arkansas. Historically, they were more widespread in these three rivers and occurred in other river systems in the Red River drainage of Arkansas.
Reasons for Decline: The reasons for their decline are uncertain but may be related to past water pollution or increased sediment deposition in their habitat. Currently, they are threatened by existing and proposed new man-made reservoirs because these alter the season flow patterns of rivers and isolate mussel populations above and below dams. There are thought to be fewer than 1,500 adult Ouachita Rock Pocketbooks still in existence.