SEM Photograph: (Borne and Cronin, ms, pl. 4, fig. 7) Scale is 0.08 mm. (Locality CJ89-15-04: Cemetery at Pueblo Nuevo, Limón Province, Costa Rica; Moin Formation). Left valve, female.
Morphologic Description: Small to moderate subrectangular carapace with distinct convoluted "brain-like" appearance of surface ridges and four large denticles located on a broad posteroventral projection.
Holotype: HVH: 9020 (Station 315, in 3m water on the south side of Tobacco entrance).