While some morphological differences exist between northeastern and northwestern populations, a phylogeographic study found little genetic support for a distinction between eastern and western populations and recommended both groups be simply referred to as northern spiny softshell turtles.
A study comparing northeastern and northwestern populations revealed some physical variations, but a phylogeographic analysis found that the genetic differences between eastern and western populations are not substantial enough to justify separate designations. Consequently, it is suggested that these groups be referred to as northern spiny softshell turtles.