norvian's picture

Wetland Snail

Observed: 6th June 2009 By: norvian
Snail1
Snail1
Description:

Wetland Snail on common reed stem

Identifications
Species interactions

No interactions present.

Comments

John Bratton's picture

In the above, I mean only

In the above, I mean only identifiable to species by dissection. It is definitely Succineidae.

dshubble's picture

Succineidae

Hi John,

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.

Dave

John Bratton's picture

Mmm. Hard to pin down exactly

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.

dshubble's picture

snail ID

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

norvian's picture

Snail ID

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?

Thanks

Norman

dshubble's picture

snail ID

Hi Norman,

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),

Dave

martinjohnbishop's picture

Look into their eyes

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.