Posterior Ridge and Posterior Slope
The posterior end of the shell may have useful features for identification, including a pronounced posterior ridge in some species, often combined with a clearly defined posterior slope.
Species of Alasmidonta have a short, steep slope.
In some species, such as A. heterodon, the ridge and slope may be more rounded than, for example, in A. varicosa. Genus Leptodea has a strongly pronounced, edge- like ridge in several species.
The posterior slope in Lampsilis species is broader and flatter.