The Neosho mucket was first described by Frierson in 1927 from specimens collected in Oklahoma from the Illinois River. It is notably larger than other freshwater mussel species in its range and can measure just over 100mm in shell length. Males are slightly larger in most bodily measurements than females. In Frierson's original species description, he reported the shell lengths of males and females as 93mm and 86mm respectively; and the male and female shell diameters as 38mm and 35mm respectively. Shell height in other specimens has been recorded as 62mm in males and 60mm in females, and is estimated to be 0.58 – 0.7 times the shell length. The low umbones project only slightly or not at all above the dorsal side of the shell.