21st February 2015 (weekly review)

It’s been a pretty quiet week with only two new species. There are a few species that I would classify as being common or easy to find locally (Candidula intersecta, Cernuella virgata, Helicella itala) that I am just not encountering – I’m guessing that these species are still hibernating. I can’t find any information on where these species spend the winter but I’d guess they spend it underground, hence why I can’t find them. Hopefully in a month or so these will start cropping up so that I can tick them off my list.

In a break from the norm I’m going to describe this weeks’ species together due to their close similarity.

Carychium minimum and Carychium tridentatum, Herald Snail and Slender Herald Snail

These species are very widespread in woodland leaf-litter and they stand out amongst leaves and on the underside of logs due to being a beautiful ivory-white colour. They are very easily overlooked, despite their colour, due to being a maximum of 2mm tall and usually a little smaller.

However, once found, they are very easily recognised as being one of the ‘Herald Snails’; a Carychium species. The trouble then lies in separating the two species in the genus. As the name suggests, the Slender Herald Snail, C. tridentatum, is proportionally narrower than the Herald Snail, C. minimum. This, as I will testify, is a tricky feature to judge without both species present or some comparative material.

Here is a wonderful picture by @BrianE_Cambs that shows the Slender Herald Snail on the left and the Herald Snail on the right. The difference in shape is quite obvious

Carychium -both- Brian Eversham

Unfortunately, as I hinted above, when one species is found singularly they are a lot harder to differentiate. The following pictures are of one of the Carychium species, but I’m not sure which one.

In this picture by @MarkGurn it is possible to make out the snail’s eyes. In this species, unlike many larger snails, the eyes are at the base of the tentacles and look like black dots.

Carychium Gurney

Tiny snail being adorable by @ASpeciesADay

Carychium Madge

Also, for a sense of scale.

Great picture by @MarkGurn of a scatter of shells in the palm of my hand. Live shells are translucent, empty shells are opaque.

Carychium hand Gurney

Fantastic picture by @ASpeciesADay of shells on a five pence – tiny snails!

Carychium coin Madge

Both species can be found in woodlands, particularly in ancient woodlands, amongst deep, stable leaf-litter. C. minimum, however, can also be found in wetland habitats. They usually only tend to overlap in slightly damp, ancient woods.

Oh, and in case you were wondering why these two species are separated out at all and are not just treated as two ends on a spectrum of variation, these two species can also be separated on distinctive internal anatomy of the shells.

I’m up to 18 species now overall. Ideally I’d like to have seen a few more species than that, but I’m sure as the weather starts to warm some species will be a lot easier to find.

2 thoughts on “21st February 2015 (weekly review)

  1. I just found your blog via @chrisitsstillme on twitter. It’s so interesting and now I’m curious how many different snails I can find in Slovenia 🙂 Can’t wait to see which snail you find next.

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  2. I just found your blog via @chrisitsstillme on Twitter. It’s so interesting I want to try it on my own here in Slovenia. Can’t wait to see which species you find next 🙂

    Like

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