How to make pictures of land snails that allow for species identification?

[bramb]

Images from iNaturalist are potentially a useful tool to collect distributional records for land snails. However, only relatively few species are identifiable on a randomly taken image. I cannot speak for other areas, but for the Neotropics many photographs will never reach the ‘research quality’ stadium and even those labelled as such are sometimes unidentifiable at species level.

Most persons seem unaware of the need to picture snails from certain directions to record characteristics that will allow other people to identify the species. It is a pity that this way many observations will never be used.

Land snails are usually either ‘flattened’ (shell diameter > shell height) or ‘elongate’ (shell height > shell diameter).
For the first type ideally 5 different views are available, like in this figure:

For elongate shells 3 views may be needed, e.g.:

Most people seem afraid to pick up shells because they think they will disturb them. When snails are crawling around, first take a few pictures of them showing the animal, if possible from different sides. The colour of the animal can help to make a distinction between similar species. Secondly pick up the snail and photograph it from different sides to show views as shown above. If the snail does not retract itself in the shell to allow a good view of the aperture shape, just touch it lightly and in most cases it will retract. Finally, when you are satisfied with your photos, put the snail back on the place where you found it; the snail may not start crawling immediately, but it will after some time.

Sometimes snails are glued to the substrate. In this case they are in hibernation and in this case you have to decide if you leave them as such (taking the risk that your images will not lead to a species identification) or that you carefully remove them from their substrate to make the different views of the shell. After finishing please place them back on the same place or a suitable place nearby; it usually means with the aperture down on the surface.

Make sure the lighting is okay and there is enough contrast with the background. It is great if something is showing that gives at least an indication of size. Fingers, a hand, or a coin are potentially useful.

A challenge will be small species especially those of < 5 mm. They may be less suitable for iNaturalist observations, especially when they are fragile. Try to image them in their natural habitat and hopefully at least a family or genus assignment can be made…

An examples from iNaturalist with comments:

Research quality and identification possible. Shows both habitat and main characteristics of the shell in multiple views; only a view from the apertural side would have been nice as addition…

Hopefully these examples give some clues about do’s and don’t’s. The core message is, if you think that a random single snapshot will give you a perfect identification, then chances are high you are mistaken. Please take a few minutes to take multiple photographs with the above suggestions in mind. Your observations will be of much more value to your fellow-nature lovers…

[BrightEmber]

Very helpful info, will be sure to follow from now on /)

[bramb]

I can add some additional examples to make clear what works and what not.

This picture is publication-quality, with good light and contrast, showing the animal beautifully. Despite the lack of size indication, this lateral view (N.B. additional to the one above for an elongated shell) still gives useful information.

Despite the good lighting and contrast and a reasonable size indication, this hibernating shell can only identified to genus level as this is the only view.

This image show a characteristic snail that belongs to a species complex. As this is the only view available, together with the locality data we know the species complex but not which form.

Research quality picture and usuable for identification, the multiple views give also an idea about the variation in this species.

Taken in the field, good for identification.

Finally I would like to draw attention to the fact that one can encounter juvenile specimens and their identification is usually impossible unless it is a very characteristic species by shape or colour pattern (which is not the case in many instances). When in doubt, take a few pictures (‘better saf than sorry’) but be prepared if no species name can be attached to them.

[janetwright]

Thank you! Is there a place on iNat for tips like this so they can be easily found when needed?

[tastyy]

To add to this: photographing tiny (let’s say under 3 mm snails) is way easier than you might think. For a long time I assumed it would require a fancy camera with a special lens or something. Turns out, a dirt cheap digital microscope can do an excellent job, more than good enough to take identifiable pictures.
Here’s a link to the one I’m using, (you plug it into the Android phone) and here are the pictures of a 2 mm snail I took, jeans in the background for scale:

You won’t win any awards for macro-photography with this, but I think it’s amazing coming from a 30$ camera, and identifiable… or would be, if anybody had any idea how to identify genus Vallonia.

As happy as I was, I don’t want to endorse one specific product too much: if you’re interested in getting one, make sure to explore similar microscopes and read the negative reviews to learn the downsides. But you absolutely can photograph tiny snails in the field with nothing but a phone and a cheap piece of equipment, and make lots of valuable observations in the process, because microscopic snails are very under-observed right now.

[ajamico]

Is this approximately the same for freshwater/marine snails? I assume having the 3 or 5 different views of the shell wouldn’t hurt, but is there anything else needed or recommended?

I have also heard that the operculum (the hard flap that covers the snail when it’s in its shell), or absence of operculum, is helpful when identifying certain species. I’ve been using @susanhewitt’s profile as a guide on how to photograph mollusks, but this post is super helpful with the pictures and examples!!

[robotpie]

These are very useful tips, will try to remember them next time I encounter a snail! How do I save this post? Or do you have a journal post regarding this info that I can save, if that is at all possible?

[roysh]

Nice tutorial, but you know about any ‘common’ species we should be aware when picking them? Like L. fulica that is a vector to nematodes

[lynnharper]

Not as far as I know. I think the only thing you can do is bookmark tips when you come across them and maybe make yourself a journal post where you can collect all the useful URLs (and then others can see them, too).

[bramb]

Thanks for your reactions.

The suggestion about the phone-addon to picture microsnails can be really helpful and I agree that these microsnails are under-reported in many areas. But you have to have a special eye for them and know how to handle them. But by all means, be my guest :) and make those images if you like.

This tutorial is now only here as I felt this information was needed when I recently compiled a paper on Ecuadorian snails (in Iberus 40, available on ResearchGate). I will make the information also available on my (now discontinued) blog on Neotropical snails (breure.wordpress.com).

The Giant African Snail aka L. fulica is indeed a pest species now in many tropical areas and one should be aware of its potential as a vector of nematodes. Once you recognise it (there are enough good identified examples on iNaturalist) you will not mistake it in the field for another species and you can ignore it.

And yes, species with a closing part of the aperture (operculum), which belong to a certain group of Mollusca, is certainly a characteristic that helps with identification. However, when the animal is dead the operculum is often lost, so when you pick up empty shells it may not be there; the species are nevertheless recognisable by experts :)