Aulacoseira granulata differs from A. muzzanensis by greater mantle height/valve diameter ratio. It differs from A. granulata var. angustissima by wider cells and lower mantle height/valve diameter ratio. Aulacoseira herzogii can be easily differentiated from A. granulata by much finer areolae, almost non-resolvable in LM, and shorter colonies. Linking valves of A. granulata are occasionally misidentified as A. ambigua, but can be distinguished by their large square mantle areolae and solid ringleiste.