Sertularia argentea

Erling Svensen Out diving today. A lots, lots of Doto's, Gods know what kind of Doto? May be Doto coronata? Also quite many E. exiguus but they are very small now. In 2-3 weeks they become bigger (small is less than 4 millimeter - big is 5 - 7 millimeter).

Christian Skauge Beautiiiful! Woulf guess D. coronata but as you know they're almost impossible... :-)

Bernard Picton These are the Doto coronata which eat Obelia geniculata I think, Erling. We need to test, probably by sequencing a bit of DNA, to see if they are the same as the one you had the other day, which was eating Obelia dichotoma (probably). There are more or less identical, but bigger, animals eating Sertularia argentea, slightly darker ones eating Abietinaria abietina, and ones which look more or less the same eating several other hydroids. Carissa Shipman will like to see these.

Carissa Shipman It will be great to find out how genetically divergent these cryptic species are from one another. Still working on photographing them and then Terry will dissect them to look at their reproductive systems. Then I will get DNA! So much to do, but I must be systematic about it.

Nicola Faulks Dived at St Abbs on sunday and found the seabed covered with hydroids and nudibranchs. Can anyone confirm which Sertularia species this is....... or if it is!

Peter Routledge Think its called a bottle-brush hydroid?? ?

Paula Lightfoot I don't think it's bottle-brush if you mean Thuiara thuja, that's very distinctive. I agree with Nic it looks like a Sertularia (common name squirrel's tail!) but Jo's book says that argentea and cupressina are so similar that their status as separate species has been questioned, so I wouldn't dare hazard a guess! Did you pick a bit?

Peter Routledge Sea fir (sertularia argentea)?? ?

Simon Parker It does look a bit like Sertularia argentea but that tends to favour silty water. The ones I've seen have been much bigger than that but that could just be down to the conditions they grow in.

Peter Routledge Were there any little ghost shrimp (caprella linearis) living in it? ?? Your photo is great but you may not have seen them if you did not know they were living in amongst it.

Nicola Faulks Didn't see ghost shrimp, but I was being distracted by the large number of different nudibranchs on them. Wonder if the cooler water temp this year means the hydroids have had a head start before being munched by colourful slugs!

Paula Lightfoot There were comments on Fb last month about the nudis seeming to be delayed in Cornwall - and certainly the Tubularia was in a very healthy un-munched state when I dived there!

Simon Parker WoRMS has quite a complex web of naming for these: http://www.marinespecies.org/aphia.php?p=taxdetails&id=117912&allchildren=1

Paula Lightfoot Dawn's call on what to enter as they are Scottish records so will go to her (ha ha passing the buck!) WoRMS has the same quote I mentioned in my original post i.e. that 'their status as separate species has been questioned' - sort of sounds like the molecular work hasn't been done yet but is needed! Marine Recorder will be updated with the MSBIAS list from WoRMS by the time data entry starts this winter, final name matching just being done now...

Nicola Faulks Yep, I put them down as Sertularia spp. They were just so beautiful, the dive made such an impression on me. :-)