Potamilus amphichaenus

Texas Heelsplitter

FWS Focus


The Texas heelsplitter is a rare freshwater mussel with a thin, smooth, elliptical shell and a straight hinge line. The beaks are slightly elevated above the hinge line. External shell color is tan to dark brown or black that fades to a lighter color on the beaks. Some specimens have low, poorly developed wing-like structures that extend above the hinge line; however, these are usually absent or lacking. The interior shell surface (nacre) is shiny and purple throughout or white to bluish-white, with a pink or purple tint along the hinge line. Pseudocardinal teeth (molar-like structures located near the beaks on the interior surface) are thin and compressed while the lateral teeth are long, thin and straight. Soft tissues are described as dirty-white or greyish-white. Individuals almost 7 inches (177 mm) in length have been collected in Texas. Texas Heelsplitter exhibit slight sexual dimorphism; females have a broadly rounded posterior margin and males are more pointed (Howells 2010b, p. 2). The base of the anterior margin exhibits a long, narrow gape, while a shorter, much wider gape is located along the posterior margin, presumably to accommodate the incurrent and excurrent apertures (Neck and Howells 1995, p. 4).

Scientific Name

Potamilus amphichaenus
Common Name
Texas heelsplitter
FWS Category

Location in Taxonomic Tree

Identification Numbers



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