Posterior Ridge and Posterior Slope

Alasmidonta heterodondwarf wedgemussel

Alasmidonta heterodon
dwarf wedgemussel

Alasmidonta varicosabrook floater

Alasmidonta varicosa
brook floater

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.

Lampsilis cariosayellow lampmussel

Lampsilis cariosa
yellow lampmussel

Leptodea ochraceatidewater mucket

Leptodea ochracea
tidewater mucket

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.