24th January 2015 (weekly review)

This week I joined the Conchological Society of Great Britain and Ireland and I encourage anyone with an interest in snail identification, snail recording or snail conservation to join. Honestly, please consider it. I haven’t regretted a single moment of my three days of membership so far.

I have been a bit slower in terms of snail finds. I think this is down to a combination of more wintry weather conditions – there’s been frost almost every day this week – and the fact that I might have found many of the commoner species in the local areas in which I’ve been searching.

Still, I managed to find three new snails, bringing my yearly total up to ten species. My three new species are:

Hygromia cinctella, the Girdled Snail

This species was kindly shown to me by Africa Gomez of @abugblog in the Pearson Park Wildlife Garden in Hull. This snail has a distinctively patterned and shaped snail. It has the form of a very shallow cone, with a rounded base, and is marked with a white line that encircles, or ‘girdles’, the shell. This white line follows a sharp ridge or ‘keel’ that runs around the shell and, combined, these features make it an easy species to distinguish. Maximum width of shell is 12mm.

Girdled Snail3

The Girdled Snail is a non-native species; first described in Britain in 1950 by writer Alexander Comfort. There are, however, records of this species that extend back to 1945 but were misidentified at the time as being Hygromia limbata. The species remained fairly restricted to the south-west until the 1970’s, at which point it began to expand dramatically, being recorded in Scotland for the first time in 2008. The Girdled Snail is native to the Mediterranean region and it surprises me how well it seems to cope – and thrive – in the UK.

Girdled Snail1

Africa pointed out to me that the Wikipedia article on Girdled Snail was a ‘stub’; an incomplete article with less than 500 words. Working together, we updated and improved the text on the page, and Africa added some of her own photos. View our success here!

Discus rotundatus, the Rounded Snail, Rotund Snail, or Discus Snail

Discus rotundatus is one of my favourite UK snails. I remember the first time I saw it being struck by its wonderful mottling in shades of brown, pink and cream, as well as that densely ribbed shell. It grows up to about 7mm in maximum diameter and is commonly found in moist, shaded places such as parks and graveyards, as well as in more natural habitats such as woodland.

Discus rotundatus3

Cornu aspersum, the Common or Garden Snail

This is one of those species that’s possible just to ramble on about endlessly. Firstly, this is the beast that quite possibly gave rise to the phrase ‘common or garden’. It’s not often you meet an invertebrate with its own idiom! It’s also the largest of the common snail species – about 40mm in width – with only two other less-common UK species, Helix pomatia and H. lucorum, being larger.

Cornu aspersum1

Cornu aspersum was, for many years, called Helix aspersa. It was then decided that it didn’t belong in the genus ‘Helix’ and was moved to ‘Cornu’. However, whilst ‘Cornu’ was the name given to material identifiable as this species, the original specimen was an aberrant scalariform individual (a snail in which the whorls of the shell grow apart from each other). This, according to some schools of thought, means that the genus name is invalid. A summary of this problem can be read here.

Numerous hibernating individuals can often be found over winter, gathered together under logs or in cracks in trees or rocks. If a hibernating snail is dislodged it should be possible to see the congealed film or plug of mucus that seals the moth of the shell; this is called an epiphragm.

Cornu aspersum2

Cornu aspersum is another non-native snail, but this one is an ancient, possibly Neolithic introduction. It is common in parks and gardens as well as other areas modified by people.

Once again, if you’re not following me on Twitter please consider doing so at @UKSnailTrail.

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