That species of Mollusca was found from lake Viljandi (https://www.google.ee/maps/@58.3483153,25.6106634,14z?hl=en). This summer.
The measurements of shell are
shell height 4,5mm
shell width 3mm
opening height 1,8mm
Dear Lennart,
this looks close to Potamopyrgus antipodarum (Tiateidae) - mud snail - freshwater .. Can you send me more clear images on the vertical elevated lines flowing from the apex to the anterior end?
The P. antipodarum we have here often has small spines following the whorls. This snail also looks a little fatter....could it more likely be an Assiminea parasitologica? Here in Oregon this has invaded the Coos Bay estuaries. This is 4-6 mm tall, rather globulous, often with a light yellow band along the suture (in young snails), shell can be eroded, and periotseum can be peeling. Here is a photo, sorry, no scale but it is about 5 mm tall. Nancy
Hi Lennart, the opening of the shell in your top photo looks too square to be Potamopyrgus antipodarum. You didn't mention whether an operculum was present. Potamopyrgus has an operculum, as in these photos of Potamopyrgus antipodarum from New Zealand, although it may be considerably more recessed into the shell than shown here. Spines are either present or absent and shell-shape can vary. Have a look at Haase (2008) as it may also help - http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1737284&fileId=S1477200007002630
Thank you all I will soon send you some complementary information about the shell.
Dear Lennart,
Although it is not my filed of expertise, I have recently been reviewing an MSci thesis dealing with mollusks here in Macedonia. And the candidate had been confronted with many taxonomic issues, some of which included species similar to yours. It appears that your specimen belongs to:
super-family Hydrobioidea
family Hydrobiidae
sub-family Belgranoiinae
Tribus Belgrandiini
Genus Sadleriana
according to the following publication:
Radoman, P., (1985): Hydrobioidea, a Superfamily of Prosobranchia (Gastropoda), Systematics. Monographs, Department of Sciences, Serbian Academy of Sciences and Arts, 547(57): 256 pages, plates 1-12.
which is also noted in Fauna Europea.
I do hope this will be helpful.
Best regards
I doubt very much that this is Potamopyrgus antipodarum, because at a size of 4.5 mm there should be a well developed parietal callus joining the equally thickened columellar margin in a shallow arc (see, for example, the pictures of Brian J. Smith above). Instead, you have no parietal callus, and a distinct angle between parietal wall and columellar margin. But Potamopyrgus shells are quite variable, and certainty can often only be achieved by anatomical and/or molecular genetic evidence. Assiminea or Sadleriana are quite unlikely, from the shell shape. I suggest you contact Peter Glöer, who is also in Researchgate.
Best regards,
Thank you all for the information. The shell did not had an operculum when I found it, unfortunately that was the only individual I found. Sometimes operculums are already gone when collecting the shells.
Based on the observed characteristics, I see a Assiminea species ........ look specimens of Santa Catarina State, Central Southern Brazil region !
Thank you, Aisur. The species was found from the shore of a freshwater lake. Assiminea is very similar, does it also live in fresh water lakes?
Dear Lennart, the brazilian specimens of the photos were found in a little stream of atlantic forest (specif locality: ... Itajaí River Basin Valley), very very far from any marine coastal edge !
Dear Lennart, on second thoughts, I got a better answer: Your shell is a juvenile Cochlicopa lubrica (O.F.Müller 1774). This is a land snail which was swept into the lake. It lives in any covered or open vegetated habitats which have some minimum amount of moisture, and is common and widespread through most of Europe. The key diagnostic feature is formation of the columellar margin, see attached drawing.
Best regards, Dietrich
I thing this is Cochlicopa lubrica or Cochlicopa nitens shell
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