Kevin,
        I looked at the images of your Anodonta specimens from Oregon and
Washington.  While my experience and literature from the Western U.S. is
rather limited non of your specimens correspond satisfactorily with any
currently recognized species.  I encourage everyone on CONCH-L with any
interest in freshwater mollusks to view Kevin's images.  At the very least you
will gain a new appreciation for the genus Anodonta.  I wonder if some agency
could be persuaded to perform genetic analysis on these animals.  Kevin, you
might contact Dr. Terrance Frest in Washington.  I do not have his address and
phone number on hand at the moment.  I believe he is a member of AMU.  If you
cannot locate his address, etc., contact me privately and I will locate it.
 
Doug Shelton
Alabama Malacological Research Center
2370-G Hillcrest Road #236
Mobile, AL 36695