See Shell Orientation and Measurements for diagrams.
At present, there is no reliable method for morphologically separating veligers of the false dark mussel from those of zebra or quagga mussels. The following guide (Larval Identification Information) can be used to separate larval false dark mussels from Asian clams. Separation of the three mussel types must wait until settlement occurs, when the mussels are at least 0.5 mm in shell length. The apophysis on the myophore plate
All three dreissenid mussels have a shelf or myophore plate located anteriorly on the internal portion of the shell. Only Mytilopsisleucophaeata has an apophysis or projection on the lateral margin of its myophore plate (as indicated by an arrow). This protrusion, used for muscle attachment, is absent in both zebra and quagga mussels. It can be observed using a good hand lens or dissecting microscope.
that is described in the Adult Identification Information section is visible in false dark mussels at this time (see Apophysis on Myophore Plate).