Truncatellina cylindrica is one of the less-common and more-awkward species of snail to find in the UK. As far as is known, it survives at three sites in the UK; one in Yorkshire, one in Bedfordshire, and one in Norfolk – though it is quite possible that undiscovered or overlooked colonies might exist elsewhere. Additionally, the snail is very little. Extremely wee. Positively minute. It grows to an absolute maximum of 2mm tall, but is usually smaller, with a maximum width of 0.9mm.
Luckily, the Bedfordshire site for this species is approximately a five minute walk from my house, though ‘site’ is a rather strong word. The snail only seems to occur on the verge between the church boundary wall and the road and, in fact, seems to be restricted to within 30cm of the base of the wall.
The church and the wall.
Another view. That’s pretty much it.
And for good reason
I found a document describing a survey for Truncatellina cylindrica sites in Bedfordshire, and this gave me some idea of how to search for the species.
I collected a specimen tube worth of soil from the very base of the wall. I was wary of damaging the site and so only took the single sample, comprising about 5ml of material. I took this home and tipped it onto a white plate. Then, using a cocktail stick, I carefully, bit by bit, moved particles of soil from one side of the plate to the other. A success came quite early on as I soon discovered an old, empty shell of my target species. I carefully transferred it to a specimen tube. Then followed a long period of a calm before I found two living juvenile shells within minutes of each other. The first was fresh but empty, but the second held a living individual. Success! The rest of my sample yielded only another old broken shell, but I was delighted by my success – four shells, two living, from 5ml of soil.
Unfortunately, the snails were too small for me to capture with any clarity using my camera, so I was forced to beg around at work for assistance. Luckily a colleague, @aspeciesaday, obliged and took these marvellous photos: