SEM Photograph:. (Borne and Cronin, ms, pl. 1, fig. 1) Scale is 0.06 mm. (Locality CJ89-20-11: Río Banano, Limón Province, Costa Rica; Río Banano Formation). Left valve, female.
Morphologic Description: Characterized by coarse reticulation and pronounced anterior cardinal angle, slightly bent dorsal margin. The dorsal ridge system pronounced and sloping rather steeply forward (Bold, 1988).
Holotype: USNM 559423 (Pit on west side of US Highway 74, north side of Lumber River near Lumberton, North Carolina, Duplin Marl, Pliocene).