Dear Anna and other ConchLers,

Although your pictures don't show the fine details, I'm pretty sure that
your juvenile specimens don't belong to the native Planorbarius corneus.
Juvenile shells of P. corneus are characterized by a typical reticulated
shell pattern, which is absent from your shells.
My advise? Don't release them in outdoor ponds in England.
Best regards,

Henk K. Mienis

----- Original Message -----
From: "Anna Robinson" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, June 08, 2007 9:37 PM
Subject: Planorbid ID


>
> Hi Everyone
>
> Does anyone know how to distinguish between Planorbella sp. and
> Planorbarius sp.? I have been sent some young freshwater pulmonate
> gastropods of the family Planorbidae. They have been selectively bred for
> different colour forms (red/spotted shells) to make attractive pets. The
> thing is, the person who orginally bred them cannot be sure if they are
> Planorbarius corneus, or Planorbella duryi. I can't tell from looking at
> pictures of ramshorns in the books. I want to put them in outdoor ponds,
> but P. duryi is not native here and I don't want to introduce an alien
> species into the wild (plus our climate's a bit chilly for it).
>
> If anyone's interested I've posted pics of the two colour forms here:
>
> http://www.waysideaquatics.co.uk/ramshorns%20001.jpg
>
> http://www.waysideaquatics.co.uk/ramshorns%20002.jpg
>
> Many thanks,
> Anna Robinson
> England

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