Marian
They may or may not have been frozen when I collected them but I think they would
have been exposed to freezing conditions off and on for quite awhile - so I was
assuming that anything I found washed up on the riverbanks or in surface mud
would have been dead. The live critters I found were some planorbulids (very
tiny) and some stagnicola, maybe half an inch tall.  I did not find any live
bivalves.  All bivalves were sphaerids, no unionids.



[log in to unmask] wrote:

> Nora:
>    One of my friends found several Cumberlandia monodonta (spectaclecase
> mussel), of the Family Margaritiferidae, Order Unionoida  (slightly more
> primative than unionids),  frozen in blocks of ice at the edge of the
> Mississippi River in Illinois.  He figured they were dead and took them home
> to salvage the shells.  To his surprise, the mussels started sticking their
> foot out after the ice melted.  I have no idea of how this can occur, and
> offhand have never seen anything about this in the literature.  So apparently
> some unionids and margaritiferids are hardier, or more adaptable to extreme
> conditions than we usually think.  What exactly did you find frozen?
> Marian E Havlik
> Malacological Consultants
> 1603 Mississippi Street
> La Crosse, Wisconsin 54601-4969 USA
> email: [log in to unmask]
> Phone/Fax: 608.782.7958