Capartogramma is closely related to Stauroneis. However, the central nodule region of Capartogramma consists of siliceous struts projecting into the interior of the frustule forming a structure resembling an "X." This structure, the tigullum, is attached to the inner surface of the valve and is connected to the pseudoseptum (Ross 1963).
The pictured specimen may be Capartogramma crucicula (Grun. ex Cl.) (Patrick and Reimer 1966, pl. 30, fig. 16.). Size ranges for this taxon are 20-36 micrometers in length, 7.5-9 micrometers in width, and 24 striae in 10 micrometers (Patrick and Reimer 1966).
Ecology
Usually, this taxon is present in brackish waters. In Lake Michigan, Capartogramma has been found in shallow, eutrophied bays (Stoermer and Yang 1969).