Dysnomia othcaloogensis I. Lea, 1857 Epioblasma othcaloogensis, the southern acornshell or southern acorn riffle shell, was a species of freshwater mussel in the family Unionidae.

It was only known from the Coosa and Cahaba Rivers of the southeastern United States.

[5] This species has been heavily impacted by dam construction, dredging, and water pollution.

[7][8] The US Fish and Wildlife Service delisted the species from the Endangered Species Act effective November 16, 2023, citing extinction.

[4][9] It appears to be closely related to the critically endangered Epioblasma penita.