Stygobromus stellmacki
Stygobromus stellmacki, commonly called Stellmack's cave amphipod is a troglomorphic species of amphipod in family Crangonyctidae. It is endemic to Pennsylvania in the United States. References

Freshwater crustaceans of North America
Crustaceans described in 1967
stellmacki
Endemic fauna of Pennsylvania
Cave crustaceans