Dear Arjan,
 
you looks like me, but some years older. I am aged 45, fat,
ugly, sometimes bald (only at home) and spezialised in
European inlandshells and Mediterranean seashells. But I
don't know Stupididae My mother is aged 87 years Do we look
similar.
 
yours Helmut.
 
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> Hello Virgilio Liverani <[log in to unmask]>.
>
> You wrote:
>
> >[...]Some friends have problems in identificating a large ( 20 cm. and
> >more ) Unio that spread a few years ago in eastern Padania plates, in
> >slowly running waters . It is about trapezoidal in shape , with thin
> >shell , and they always crack in the middle , regardless the way you
> >treat or store them .
>
> Must be Anodonta cygnea (L., 1758). The post mortem cracking of the
> shell seems to be a typical feature of this species.
>
>
> Arjan (79 years old, fat, bald, ugly and specialized in Stupididae)
>