Guides for identifying marine gastropods and bivalves

The very variable Variegated Scallop - CC image by Hectonichus

The seaside being a popular place, there are lots of guides to choose from when you're starting out. For example, we have copies of the Oxford Photographic Guide to Sea and Shore Life of Britain and North-west Europe, and Hayward's Sea Shore of Britain and Europe (Collins Pocket Guide) (this one has drawings not photos). These are great because they give you a good overview of what's out there, and you can start to see which family is probably the right one for your specimen. Then you'll need to dive into the detail to pick out your exact species.

I've found this downloadable shell identification guide by Ian Wallace for the Liverpool Bay Marine Recording Partnership to be excellently produced. He's very good at pointing out the distinguishing features of the different species - especially for bivalves (bivalves can be a bit of a headache). I like it a lot. I can print one off for you in colour if you like. We're not in Liverpool of course, but there will be much overlap with species you might find more locally.

The Conchological Society of Great Britain has useful online habitat-specific species lists: There are species you might find on sandy and muddy shores and on rocky shores. The names link to pages giving detailed descriptions and distribution maps.

But even the great guides above are essentially pictures with descriptions, and you will remember that you've got to show your use of a key for your assessment. Plus, with many species you'll feel more confident about your identification (and learn a lot) by using a key - it's not always easy to just match your shell to a picture.

CC image of a bivalve by Muriel Gottrop

A revelation to me last year was getting hold of the classic 'British Bivalve Seashells' by Norman Tebble (Tebble's a great name is it not.. it sounds like a sort of bivalve to me?!). It's long out of print and I have one copy at the moment, but you're welcome to come and use it in the lab. You'll have to steel yourself to learn some technical language about the different parts of a shell. It will make your brain hurt (this proves the knowledge is going in). But Student H and I got stuck into it with some success, so I know I can help you if you want to give it a try. The National Museum of Wales has a website called 'Marine Bivalve Shells of the British Isles' (but the key wasn't working recently?) - I think it's pretty much based on Tebble's keys.

That website also has an interesting page on all the terminology for the parts of the bivalve shells and their shapes (unfortunately it's not a very well set out page as you have to scroll across it). It's very detailed and you may think it a bit advanced for your needs, but I think it's useful if you're working your way through a key like Tebble, and want to describe your shells in an appropriately malacologist-like way.

 Other key options (for shells other than bivalves) can be found in Hayward and Ryland's 'Handbook of the Marine Fauna of North-West Europe' (of which we have several copies).

There's another key by Crothers in the Field Studies Journal for 2003 but it does frequently mention live animals, and it's likely your shells will have been vacated, so it may be of limited use.

 It can be a bit frightening  using the keys, as you'll have to get to grips with some terminology, but if you've already got some idea of what family your mollusc is, it's not so bad. Anyway, we can look at them together if you like.

All the books seem to use different names, resulting in maximum confusion. But you can check the most up-to-date names using the Natural History Museum's Dictionary of UK Species. If you've got a bivalve, the National Museum of Wales' database of  'Marine Bivalve Shells of the British Isles' has a good search function that will give you the latest name if you put in a defunct one.