Theliderma metanevra

Theliderma metanevra, common name the monkeyface, is a species of freshwater mussel, an aquatic bivalve mollusk in the family Unionidae, the river mussels.

It is native to the eastern United States, where it lives in large to medium-sized rivers. Although it has been extirpated from certain sections of its range, it is still widespread and fairly common.