edrinkwater's picture

Snail 25

Observed: 17th July 2012 By: edrinkwateredrinkwater’s reputation in Invertebratesedrinkwater’s reputation in Invertebratesedrinkwater’s reputation in Invertebrates
Snail 25
Species interactions

No interactions present.


edrinkwater's picture


Ops, I forgot to put the size on this one. It is between 6-7mm. Thank you.

dejayM's picture

possibly Lymnaea truncatula

Is it too big for P.antipodarum at 6mm? Usually at 2-3mm
A lookalike is Lymnaea truncatula (at 7-12mm)

martinjohnbishop's picture

Not too big

The average height of the shell is approximately 5 mm; maximum size is approximately 12 mm. The snail is usually 4–6 mm in length in the Great Lakes, but grows to 12 mm in its native range.

Being a prosobranch with an operculum the lip make a full circle as in the photograph. Lymnaea truncatula is not like this, the lip not being thickened against the body wall but only at the free edge of the last whorl.


dejayM's picture


Yes Martin, thanks.
I am about to post up a sighting from a new area near Inverness. They are nearly black, certainly very dark grey and none, in the thousands I found, were bigger than 2.5mm.
Following your link to this http://en.wikipedia.org/wiki/File:Potamopyrgus_antipodarum_shell.png suggests the rim (lip) of the opening to be complete all 'round.
But this http://en.wikipedia.org/wiki/File:Galba_truncatula.jpg (L.truculata) is incomplete.
Do you think that's a fair indicator for separation (from a photo)?

martinjohnbishop's picture


Yes, that is the point I was trying to make.

dejayM's picture

my post