Difflugia tuberculosa  Hempel, 1896

Diagnosis: Shell compressed, irregularly ovoid in shape, slightly constricted around the pseudostome and prolonged into a short neck. Fundus rounded and ending in one or more blunt processes, like D. nodosa. On each of the compressed sides there are three small prominences or tubercles. Shell about four times longer than wide. This species is characterized by having three small tubercles on each of the compressed sides. These tubercles are arranged on each side of the test so as to form the angles of a triangle.

Dimensions: Hempel (1896): Shell length (excl. without spines) 143 µm, width 111 µm.

Habitat: Freshwater. Lake Matanzas, Illinois, USA.