Rotundaria succissa
Rotundaria succissa is a species of bivalve in the family Unionidae. It is native to the United States, where it is endemic to the Apalachicolan Region of Alabama and Florida. Here, it is found in the Choctawhatchee, Escambia, and Yellow River systems. It is considered to be a somewhat "hardy" mussel in terms of tolerating poor water quality, and its populations appear to be stable. It was formerly classified under "Quadrula", but in 2012 it was moved to "Rotundaria" based on genetic evidence.