mick's picture

Large garden snails - Helix lucorum

Observed: 9th June 2011 By: mick
London Natural History Society
mick’s reputation in Invertebratesmick’s reputation in Invertebrates

These 45mm+ snails are regulars in our back garden.
The photo on the right is of a live specimen from the garden together with a shell of Helix pomatia collected elsewhere.
12 July: Now confirmed as Helix lucorum.

Species interactions

No interactions present.


Sam Griffin's picture

Could this not be Helix pomatia?

Could Mick or Andy explain why they are sure this is Cornu aspersum? I'm sure you are right - but I'd be interested to know which features seperate the C. aspersum from H. Pomatia.. Thanks!

mick's picture

At first I wondered if they

At first I wondered if they were H pomatia.
Robert Cameron's FSC key says that Helix aspersa (Cornu aspersum) has a wrinkled surface (don't really know what that means), usually under 40mm and the umbilicis is completely sealed by the lip.
H pomatia is described as creamy, with coarse growth lines, no wrinkles (?) and the umbilicis remains visible as a tiny chink.

I've see H pomatia quite commonly in the chalk of the North Downs, but it should not be in an urban garden in my part of the world. I suppose one or more could be transplanted, but these have been appearing in my garden for several years.

mick's picture

Further investigation

Further investigation indicates that Sam may be right here!! I went out and collected some more specimens and took the second photo, together with a collected Helix pomatia shell (from a chalk downland site, not from my garden). The umbilicis looks exactly the same. I can only assume that this population has arisen as a result of a transplant, like a garden escape in reverse. They are generally darker than 'wild' Helix pomatia, perhaps because of the low calcium diet.

Assuming I have it right this time, tick and star to Sam. Thanks.

Sam Griffin's picture

Helix pomatia

I absolutely cannot claim to be any kind of snail expert, but the 'giss' didn't feel quite right! I'm pleased my question spurred your further investigation which may have revealed something interesting - but it was a complete fluke! I'll ID it as H. pomatia, thus contradicting initial ID, in the hope that someone who is a snail expert can comprahensively resolve it..!

bobthebirder's picture

roman snail

And I'm even less of an expert but I've agreed with the roman snail ID on the basis that these look exactly like the shells I collected at a known roman snail site near the M25.

Bob Ford

martinjohnbishop's picture

Helix lucorum in Chiswick; Italian restaurant nearby?

In Helix pomatia the animal's body surface is cream coloured and the shell is pale and weakly banded.

In Helix lucorum the animal's body surface is dark grey and the shell is strongly coloured.
I do think the animal in the photograph is H. lucorum as it has a dark grey body.

Kerney and Cameron state of H. pomatia
"Confusion with ... other large species imported as food is possible"

According to this article it has "reached" Paris http://molluscs.at/gastropoda/terrestrial/helix/lucorum.html so why not London?

Try asking:
Hon. Non-marine Recorder: Adrian Norris
17, West Park Drive, Leeds, LS16 5BL
Email: nonmarine@conchsoc.org