In Sellaphora japonica, rounded apices are broader, relative to maximum cell breadth, than they are in either S. javanica or S. subfasciata. Additionally, S. javanica does not have a central area bounded by shortened, marginal striae. While S. subfasciata does have this feature, the striae do not alternate in length as consistently or noticeably as they do in S. japonica. Lastly, central striae in S. javanica are less dense and uniformly spaced than central striae in S. japonica.