The ventral margin of E. yellowstonianum is slightly expanded, as compared to the more expanded ventral margin of E. reimeri. The valves of E. yellowstonianum are narrower compared to E. reimeri. The two species overlap in striae count. Further work may show that E. yellowstonianum and E. reimeri are conspecific.
While there have been a number of reports of E. sinicum from North America, this species has acute apices, a finer striae count (12 in 10 μm) and finer areolae count. The density of areolae within a central, dorsal stria is 7-8 in 5 μm.