Compared to Mayamaea atomus, Fistulifera spp. and Navicula subminuscula, C. molestiformis has parallel striae throughout the valve, a straight raphe, and is larger than 10 µm. The areolae can be resolved in N. subminuscula in LM, but are not discernable in C. molestiformis. The apices of C. submolesta are capitate in comparison to the more rounded or subrostrate apices of C. molestiformis.