Elliptio spinosa, the Altamaha spinymussel, is an endangered species of freshwater mussel in the family Unionidae. They live in southeastern Georgia in the Altamaha river and its tributaries. It is one of three species of North American spinymussels which are recognizable by their prominent spines. The Altamaha spinymussel genetically diverged from the other spinymussels 3.76 million years ago. This suggests that their spines evolved separately from the spines of other North American spinymussels. The Altamaha spinymussel is on the Endangered Species Act because of many threats with the most prominent threats being habitat loss, decrease in water quality, shrinking range, small population size, and vulnerability to disturbances.