Paul,

I am just a beginner at freshwater mussels but my first guess would be
Elliptio complanata (Lightfoot). Do you know where it was collected?  Both
state and biotype (lake, stream , river, cobbles , muck etc.) would be
helpful.

Beth DeHaas
Whitefield, ME
-----Original Message-----
From: Paul Monfils <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Monday, December 03, 2001 6:42 PM
Subject: [CONCH-L] Unio ID ?


>Hi All,
>
>I am trying to ID a rather large (120 mm) fresh water bivalve from the
>southern USA.  I have visited some unio sites, but after randomly
>downloading and discarding pictures for a half hour, I haven't found it.
> I don't expect a positive ID from a description, but if anyone has
>suggestions, I can narrow down my search, and hopefully find it.  Or, if
>necessary I can produce a picture and post it on the web.  But for now,
>here is the description:
>
>120 mm, rather solid and heavy, shiny black periostracum overlying a
>pearly white exterior.  Sculpture consists of heavy concentric growth
>ridges.  No radial sculpture or tubercles.  Umbos are near the anterior
>end.  Anterior end is narrow and rounded, posterior end is wide, squared
>off, and more inflated than the anterior end.  Interior is a lovely
>violet-pink color. Anterior to the umbos are large hinge teeth on both
>valves.  Posterior to the umbos, a sharp ridge or keel on the right
>valve fits into a deep groove on the left valve. Any suggestions?
>
>Regards,
>Paul M.
>
>