Mussels (Bivalvia, family Unionidae) known from the Poteau River. This is an incomplete list as some specimens are still being identified. *Not found in our sampling, but found by John Harris in his survey of the upper Poteau River in Arkansas (Harris, J.L. 1994. Survey of the Freshwater Mussels (Mollusca: Unionidae) of the Poteau River in Arkansas).
| Actinonaias ligamentina | mucket |
| Amblema plicata | threeridge |
| Arcidens confragosus | rock pocketbook |
| Elliptio dilatata | spike |
| Ellipsaria lineolata | butterfly |
| Fusconaia flava | Wabash pigtoe |
| Lampsilis cardium | plain pocketbook |
| Lampsilis hydiana | Louisiana fatmucket |
| Lampsilis siliquoidea | fatmucket |
| Lampsilis teres | yellow sandshell |
| Lasmigona complanata | white heelsplitter |
| Lasmigona costata | flutedshell |
| Leptodea fragilis | fragile papershell |
| Ligumia subrostrata | pondmussel* |
| Megalonaias nervosa | washboard |
| Obliquaria reflexa | threehorn wartyback |
| Obovaria jacksoniana | southern hickorynut* |
| Pleurobema sintoxia | round pigtoe |
| Potamilus purpuratus | bleufer |
| Pyganodon grandis | giant floater |
| Quadrula nobilis | Gulf mapleleaf |
| Quadrula nodulata | wartyback |
| Quadrula pustulosa | pimpleback |
| Quadrula quadrula | mapleleaf |
| Strophitus undulatus | creeper |
| Toxolasma lividus | purple lilliput* |
| Toxolasma parvus | lilliput |
| Tritogonia verrucosa | pistolgrip |
| Truncilla donaciformis | fawnsfoot* |
| Truncilla truncata | deertoe |
| Utterbackia imbecillis | paper pondshell* |
| Villosa arkanasasensis | Ouachita creekshell* |
| Villosa iris | rainbow |
| Villosa lienosa | little spectaclecase* |