Did you know that there are two species of flat periwinkle?
That they look almost identical to each other?
That in many cases the only way to tell them apart is by dissection?
Yikes! So what can we do to record them as best we can? Well, fortunately for us they prefer different zones on the intertidal. Littorina obtusata feeds on adult Egg Wrack and Bladder Wrack and therefore favours the middle shore. It’s lookey-likey cousin Littorina fabalis (which used to be called Littorina mariae – if things weren’t confusing enough!) prefers dining on serrated wrack and therefore favours the lower shore. SO! – you can help us differentiate by taking a great ID photo of the snail including the seaweed on which you found it and submit it with your record.
If you don’t find it on seaweed or just find the shell, dont’ worry – just submit your record with a photo as the joint group name Littorina obtusata/mariae which will come up as an option if you type in littorina… Simples!