Osilinus lineatus

Ian Smith “For brilliancy of colouring and diversity of painting, we have nothing comparable among our native shells, to this beautiful little Phasianella [=Tricolia pullus].” (Forbes & Hanley, 1849.) Soft parts are pretty smart too. Set of images with pop-up interpretive notes on Flickr, with full image-linked account under image 2 at http://www.flickr.com/photos/56388191@N08/collections/72157633613018744/

Sheilah Openshaw http://www.google.co.uk/imgres?imgurl=http://www.marlin.ac.uk/imgs/o_calziz.jpg&imgrefurl=http://www.marlin.ac.uk/lzspeciesreview.php?speciesid%3D2849&h=600&w=800&sz=16&tbnid=62-2PTDSQPgseM:&tbnh=95&tbnw=126&prev=/search%3Fq%3Dtopshell%26tbm%3Disch%26tbo%3Du&zoom=1&q=topshell&usg=__pv2oDXBfo7SkY89Eypr4CcoppMg=&docid=06wScToUdTCP-M&sa=X&ei=eCUCUvCRLYH50gXW5YCwCA&ved=0CC8Q9QEwAA&dur=0 Topshell

Paula Lightfoot I love these! I collected loads of the shells on Herm but have never seen a live one, those photos are amazing!

Ian Smith Thanks Paula. I've never found a 7mm adult alive. As with sea slugs, the smallest juveniles are hundreds or thousands of times more numerous than full grown ones - to maintain stable populations, on average all but one or two of the hundreds / thousands born from spawning of an individual need to come to a sticky end before they can in turn breed successfully. I often find 5- 10 juveniles by collecting a marge tub of filamentous red algae from shallows or deep pool at LWS and searching it small bit at a time under low power stereo microscope. But you need to be on S or W coast Britain round to Orkney. Maybe divers could try the technique?

Paula Lightfoot I'm sure we could! No point looking here in Yorkshire I guess (although the NBN Gateway shows 2 east coast records...?) but I will look for them in Strangford Lough!

Simon Taylor These and your other pictures on flickr are really superlative images Ian, truly fantastic. Please please post a link to them in the British Marine Mollusca group, or may I?

Simon Taylor Paula, are you at Strangford Lough later this month? If so, I'll see you there. Incidentally, did you which datasets contain those spurious Tricolia records from Yorkshire? Not the Conch Soc I hope. If it was, I will endeavour to re-check them and have them removed if required. I'm very keen to improve the veracity of the Conch Soc marine dataset.

Paula Lightfoot Yes can't wait! With David Kipling, Sarah Bowen and Mandy Knott, we will see you there :) One record is in the Conch Soc dataset, the other is not (and its not in the Seasearch dataset either before anyone asks)

Simon Taylor Ok, as soon as I can get Recorder 6 and Windows 8 to work happily together I will get stuck into investigating these odd records. I'm very keen, and I know Ian Smith shares my feeling on this, to ensure the Conch Soc dataset is as reliable as possible. Really looking forward to meeting some people at Strangford who I've only ever met 'virtually' before.

Ian Smith As there is a Dutch name for Tricolia pullus, I wonder if any Dutch members can tell us if there are North Sea records/images from the Netherlands? If so, it would lend credence to those on NBN. Simon Taylor, you're welcome to put a link on BMM, but please add a note of apology for double posting as most members are also in this group.

Paula Lightfoot There are 9 Dutch records on GBIF but only 3 are georeferenced (one is a fossil!) and they are from south Holland right on the border with Belgium - so not much further north than the UK records from Kent.

Paula Lightfoot On a similar subject, records of Gibbula umbilicalis and Osilinus lineatus for the east coast of Scotland have been removed from the Seasearch and Porcupine datasets so will disappear from the NBN Gateway next time those datasets are uploaded :)

Marco Faasse Ian Smith and Paula Lightfoot, the marine fauna of The Netherlands is extremely poor in species (let's say like Kent, but even worse). Most of the coast is sand; rocks are absent, the only hard substratums being coastal defense works. The result is that beachcombing is much more popular than rockpooling etc. Many records of rare species pertain to specimens washed ashore on floating objects coming (mostly) from the south. I understand that people are happy to record species, but recording beached specimens has led to much confusion due to people from other countries assuming these records pertain to specimens living on our coast. Tricolia pullus is an example of a species that has only been recorded washed ashore or fossil in The Netherlands. The different character of our shore also means that the absence of Tricolia here doesn't preclude its presence in Yorkshire ...

Simon Taylor Very interesting comment Marco. I think there is room for beach recording so long as the nature of the record is made very clear. Personally I tend to only record obviously fresh-dead beached shells, particularly as in some areas in East Anglia (and presumably in parts of mainland Europe) there are coastal exposures of very fossiliferous strata, e.g. the Red Crag, containing specimens of extant species which could easily be confused with modern shells.

Marco Faasse I agree with you, Simon Taylor, the problem is not with the recording of beach finds, which may be interesting indeed, but in recording the nature of the record (which is missing even in some publications in scientific journals!). Citations and compilations should be very careful to avoid misunderstandings.

Paula Lightfoot I recorded Tricolia pullus on several dives in Strangford last week, both by collecting red seaweeds during the dive as Ian suggested, and I also spotted and photographed some underwater. So yes, divers can easily record live specimens of this beautiful species if they're in the right area and habitat.

Ian Smith Congrats. Nice picture of an adult, Paula . I wish I could find one, as well as juveniles, on the shore. Last week I collected red weed at exactly the same spot as I got juveniles 4 weeks earlier. This time not one! As compensation I got all four spp. of British Lacuna, though all juvenile at this time of year. I saw not a single sea slug while on the shore, but microscope examination of weed and some stones produced 9 spp. including a brilliant Hermaea bifida (8mm - largest slug found) on Griffithsia, and Placida domingo (dendritica) on the single small strand collected of Bryopsis plumosa.