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Top Snail

The Top Snail Trochoidea elegans is one of the most distinctive British species, and one of the rarest. It inhabits chalk grassland where there is bare ground and chalky rubble, especially on steep slopes which help to maintain eroding, bare ground conditions. A dry, sunny microclimate will make it feel at home here, as it is an introduction from the Mediterranean, first recorded in Britain in 1890. Michael Kerney’s (1999) atlas shows 4 dots for it, in Kent, Surrey and Sussex.

I have always wanted to see it and got a chance to look at Hawkshill Down (TR 3736 4981), south of Deal on Tuesday morning. It was another damp day with occasional drizzle which for once was absolutely fine with me – perfect weather for snails!

Unfortunately, I was only able to find empty shells, after a pretty thorough fingertip search. And none of them even look like they’ve held a living snail in recent years. In fact, most of them were in the spoil-heaps outside abandoned rabbit burrows which suggests they may have been dug up from down in the soil. I reckon Trochoidea elegans is extinct at this site, as already suggested by Ron Carr after a visit in 2005. Why has it gone? Well, there’s very little bare ground, no livestock grazing, the rabbits seem to have gone, and the scrub and coarse vegetation are moving in.

Trochoidea elegans: empty shells only and all looking like they've been empty for a few years.

Former site for Trochoidea elegans.

Should we care? I guess not, for a non-native species. Only it demonstrates a problem that many species face and shows how easily small populations can blink out. It wouldn’t take much management effort to restore the right habitat conditions to that bank but as for Trochoidea elegans – when it’s gone it’s gone.

I would be very interested to hear from anyone with news of the other British populations of Trochoidea elegans: Lydden, Kent; Chaldon, Surrey; and Denton, Sussex.

Compensation was provided in the form of my first Marbled Whites of the year, a superb Lapidary Snail Helicigona lapicida, some Porcellio dilatatus woodlice in debris down an old rabbit burrow, and at the edge of a nearby wheat field some Prickly Poppies and Alsike Clover (tick!). But searching suburban green spaces on hands and knees is a risky business and there was a depressing inevitability to my encounter with a dog turd.

Lapidary Snail Helicigona lapicida. A declining snail. I think the name refers to the finely roughened texture of the shell, resembling something a lapidary would use to polish a gemstone.


5 Comments

  1. Trochoidea elegans was the first truly ‘rare’ animal I ever saw, found by my mother when we were out for a family ramble across the South Downs behind our new home in Newhaven, Sussex, on 17 September 1967, and instantly recognized by my father Alfred Jones. There were thousands of them, scattered across several hectares of long-trodden sunken pathways through the grazing meadows. This, it turned out, was the largest colony in Britain.

  2. Re lapidary, I’d always assumed that it referred to the shell’s sharp edge, resembling either a cutting tool or a gemstone that has been cut. Have only seen it a few times, always good to find.

  3. markgtelfer says:

    Richard, It is one of the great disappointments of my childhood that my parents never showed me any rare snails.

  4. Andy Murray says:

    Fantastic- I’ve just got permission to look at Eden for springtails, but turned up the Pseudotyphloscia sp. which was nice as well as some nice milllipedes. Back in tomorrow for a proper explore….

  5. markgtelfer says:

    Good stuff Andy, will be interested to hear what you discover.

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