Eunotia charliereimeri also has two rimoportulae per valve but is broader, more coarsely striate, more curved, and with parallel margins in large valves. Other comparable taxa do not have two rimoportulae per valve. Eunotia bilunaris is narrower and more finely striated. Eunotia incisa is generally smaller and has a nearly straight ventral margin. Eunotia pirla and Eunotia carolina also have nearly straight ventral margins.