Conical land snails for id - and are they mating?

[Bruce Williams]

Took these pics yesterday at Salcey Forest. All three snails on same well rotted oak log.

This is my first attempt at using the FSC book "Land Snails in the British Isles" to identify species so I would really appreciate comments.

1. The shell is sinistral, narrow and spindle shaped.
2. Shell is widest above the mouth not at the mouth.
3. Shell has radial ribs.
4. Shell is about 12mm long.
5. Mouth is wide (not wider) relative to height.

Based on the above and the line drawings in the book I would say they are family Clausiliidae and species Macrogastra rolphii.

So my first question is: Do you agree?

Second question is: Do you think the pair are mating?



Bruce

[haematocephalus]

Bruce,

My reaction to your excellent photos is that they are the right shape for Clausilia bidentata, with both shell and mouth opening slightly too narrow for Macrogastra rolphii. However, I've never knowingly seen rolphii so I'm not sure of the distinction.

According to the books rolphii is usually found at ground level (including under fallen wood), whereas bidentata is much more likely to climb.

If you still have the specimen, you may be able to poke it (gently ) so that it retracts further into the shell, allowing you to see the other characters inside the mouth opening.

Don't know about mating behaviour, be interested to see what others think.

Martin

[Tiggrx]

I also am not familiar with M. rolphii - but would venture to suggest your snails are Clausilia bidentata - I have certainly found this species in Salcey Forest in the past.

[Meta menardi]

Originally Posted by Bruce Williams

Second question is: Do you think the pair are mating?


Bruce

That is difficult to call, it is along time ago and I seem to remember it being a bit more... pink? but then that is just my memories.

[Bruce Williams]

I should have mentioned that the oak log was lying in the leaf litter.

Martin and Tiggrx - I'm very open to your suggestion of Clausilia bidentata as it's just one step further along the AIDGAP identification key.

I had considered it as a possible id, particularly as the key for C. bidentata reads: "Shell darker (may be greyish when old)." which seemed to fit the apex-end colouring quite well.

I originally rejected C. bidentata after reading the following key: "Spiral striations on shell not evident". I now realise that I had wrongly interpreted that to mean that the ribs were not evident. To be honest I still don't understand what is meant by "spiral striations".

Unfortunately Martin I didn't collect a specimen snail so can't carry out any further checks.

Tiggrx, If you see a chap with a beard turning over logs and accompainied by a Vizsla dog (in Salcey Forest) do come over and say hello .

Having now reworked the key and taking into account your comments, I have revised identification to C. bidentata.

Meta menardi - Yes....I think the visible soft part is just the foot .

Bruce

[Bruce Williams]

I came across this amazing website while Googling for images of Clausiliidae:

Conchology, Inc - Search Results - CLAUSILIIDAE

It has a HUGE number of images for each species. However to be frank, even with all those images I find it difficult to decide with 100% confidence on species. Ribbing on both C. bidentata and M. rolphii seemed more pronounced than in my photos - but could be result of their studio lighting.

I did wonder about Cochlodina laminata?

Bruce