Aphodius fossor is the largest species of Aphodius in North America. The genus Aphodius is quite common in various dung, especially cattle, and is characterized by a very expanded clypeus covering the mandibles from above, and by having two or more ridges (carinae) running transversely on the meso and metatibia. I have found this species to be one of the most common scarabs in dung throughout North Dakota.