Wetland Snail on common reed stem
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In the above, I mean only identifiable to species by dissection. It is definitely Succineidae.
How do you tell Succineidae apart from superficially similar Limnaea without seeing the aperture? To me, most Limnaea have a more pointed spire than Succineidae, but not all.
Mmm. Hard to pin down exactly why. Being out the water is a big clue that it is not Lymnaea. Lymnaea will crawl about on wet mud quite happily, but I've never seen one heading up a dry reed stem. Also, succineids look too big for their shell. I think the eye stalks are more triangular flaps in Lymnaea, rather than the cylinders you see in these photos. Body colour is more uniform in Lymnaea, whereas this one is quite speckled.
In the new checklist, several Lymnaea spp are now in different genera, but I think to most of us non-conchologists, Lymnaea will remain what we call them for the foreseeable.
Ta for that - when I posted the initial ID, I was tempted to put Succineidae, but couldn't have said why, hence the broader choice in the end. Your comments do sum it up well,
Dave and John, thanks for your comments. I would agree with John in that we always see these snails on the stems of marsh vegetation, often in large numbers during the summer, and their bodies always look too big for their shells.
Do you have any knowledge of their ecology?
I've just noticed that on an old species list for the reserve I had identified it as Oxyloma pfeiffen, this was from a book. It certainly looks very similar, how do you differentiate between them down to that level?
Oxyloma pfeifferi (not pfeiffen) is a common succineid found all over Britain in a variety of wetland types. In a lot of cases, they can't be identified to species level without dissection, and in formal recording (e.g. for the production of an Atlas), only records confirmed by dissection would be accepted. There's a lot of info on snails at www.conchsoc.org/index.php (Conchological Society),
As you say, Lymnaea tentacles look quite different.
Lymnaea - eyes located at the base of their triangular non-retractile tentacles.
Succinea - eyes located at the tips of their cylindrical retractile tentacles.
Lat/Lng: 51.385097347447, -0.16246783739916
OS grid ref: TQ279667
Small urban wetland nature reserve. Swap and willow carr vegetation.