This one was surprisingly straightforward to identify. The lack of a sclerite at the base of the lateral hump narrows the field quite a bit, and the other options followed fairly obvious characteristics to Clostoeca, which only has one species, Clostoeca disjuncta.
Described by Baumann, R.W. (1996) Three new species of Amphinemura (Plecoptera: Nemouridae) from eastern North America. Entomological News 107, 249–254.