Posterior Ridge and Posterior Slope

A heterodon Full Posterior

Alasmidonta heterodon
dwarf wedgemussel

A varicosa Full Posterior

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.

L cariosa Full Posterior

Lampsilis cariosa
yellow lampmussel

L ochracea Full Posterior

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.