Diadumene cincta

Andy Horton Diadumene cincta

Andy Horton Translucent column is distinctive

Andy Horton I identified these as Diadumene cincta

Elly Jeurissen Sea life from the fairly cold waters in my home country Anemone (Diadumene cincta) @ saltwater Lake Grevelingen, The Netherlands Canon G12 in Canon WP-DC34 UW-housing; F8; 1/500; ISO 80 Inon UCL-165 macro lens, Single strobe, Sea & Sea YS-01

Bonnie Bonomé "Fairly" cold?! You are an optimist! :-)

Reiner Tempelhof Nice Picture

Ofrit Bar Prachtig!

Ellen Cuylaerts Beautiful Elly!

Elly Jeurissen Hahaha, that's right, Bonnie. I''m an optimist indeed. But I only dive in Dutch waters during summertime, when water temperature is between 15 and 20 degrees C. That's fairly to me :-D

Elly Jeurissen Thanks Reiner, Steffen, Ofrit and Ellen :-)

Erling Svensen Could this be a M. pallidus? Aprox. 2,5 cm high and disc also about 2,5 cm?

Andy Horton Most probably Metridium

Estefania Rodriguez Metridium? does not look like it...

Andy Horton cf. http://www.facebook.com/photo.php?fbid=10150741261039203&set=o.224626804295339&type=1&theater

Meg Daly I think this looks like a Diadumene cincta...but they're hard to tell from small Metridium. I defer to folks like Andy who see them alive more frequently!

Andy Horton This is an interesting and sometime hard to identify species: http://www.marlin.ac.uk/speciesinformation.php?speciesID=3149 Does anybody find this small sea anemone? Diadumene cincta

Erling Svensen I see it in South West Norway. I agree it is very dIfficult to identify.

Sarah Bowen Yes, we've seen it in the Cleddau Estuary, Pembrokeshire. Pretty little thing that can be confused with baby Metridium senile!

Andy Horton Sarah: I had the same ID problems.

Penny Martin me too .... I'll post a photo ... not sure if it is Metridium pallidus ??

Erling Svensen Do anybody know why this Sagarthia elegans anemone have a couple of very long arms? The anemone is only 1,5 cm across the disk.

Andy Horton The tentacles enlarge and subject of my talks at the Coelenterate Society and probably Porcupine Society talk way back in the past (20th century). It was on Sagartia troglodytes.

Andy Horton Feeding As many as five large 'catch tentacles' seem to be enlarged versions of existing tentacles, and these can be best observed in aquaria. They are usually translucent. In the wild, this anemone is known to eat shrimps and small crabs that are 75% of the bulk of the anemone, and these tentacles would be necessary to manoeuvre the prey to the mouth. They will actively search the surrounding water for prey of mostly small crustaceans. Catch tentacles are controversial in a number of ways: 1) They are recorded as not existing in preserved specimens in species like the Plumose, Metridium senile, in which they are actually quite common. This is because they are not separate tentacles. http://www.glaucus.org.uk/S-troglo2.htm Pictures are still on the old slides and have not been copied.

Erling Svensen Thanks Andy. Very informable and I did not know. Very nice to observe and learn new things.

Andy Horton These are my anecdotal observations and conclusions from the evidence. In 1993 it was new.

Ron Ates Nice picture. These elongated tentacles have been seen on several more species of acontiarian sea anemones. In S. elegans since at least 1860 or so. They are called fighting tentacles (previously catch tentacles) for their ability to damage neighbouring sea anemones and other animals.

Andy Horton I tested the this "fighting bit" in both Sagartia troglodytes and M. senile by putting the sea anemones next to each other. The tentacles did not enlarge. I put live food in the water and tentacles cames out to try and catch the food. In Actinia equina the acrorhagi seem to be used for fighting, or possible the tentacles do the opposite and retract when they bump into each other. Best results occur when Actinia is matched up against an Anemonia Snakelocks. I repeated the feeding experiment about a hundred times. The catch tentacles did not always appear but they did at least a dozen times out of a hundred, possible more. In eh Beadlet, Actinia the tentacles retract most readily but also in M. senile and the A viridis as well.

Ron Ates Hi Andy,

Ron Ates Hi Andy,

Ron Ates Hi Andy, you raise interesting points, let's compare notes. I am new to this facebookstuff, sorry for that. Things may go wrong as I must learn. I agree that the evidence can be tricky. For instance Diadumene cincta, which is very common in the Netherlands shows fighting tentacles all the time. Yet I have never seen aggressive interactions with other anemones. However, Manuel (1981:122) witnessed it in a fight with Anemonia viridis (your snakelocks) and the latter was killed. So I conclude that elongated tentacles may kill competitors. Another thing that seems to be clear from the literature is that food never adheres to these elongated tentacles. Would you like me to send you pdf's of what I have on this subject?

George Brown Welcome to facebook Ron. Your pdf's sound interesting.

Andy Horton Yes please. There is a files section that *.pdf files can be uploaded to. I don't think I have seen Sagartia actually eat at all. I have seen them spit out tiny Shore Crabs. More later.

Ron Ates Please see Purcell (1977) for an account of fighting tentacle behaviour in the plumose anemone Metridium senile. Food does not adhere to them. They are used in aggression. As far as Sagartia elegans is concerned I have seen it damage and chase away snakelock anemones in my aquarium. Admittedly, in other species the function of elongated tentacles is not always as clear. I will now try to upload part of Purcell (1977), keep your fingers crossed.

Andy Horton The main function of my observations was that they were elongated tentacles rather than separate tentacles.Then there was how to induce the sea anemones to eat which was achieved by introducing food to the water &/or fresh sea water and it was then that the tentacles were observed. When tentacles of other sea anemones meet each other I observed retraction more often than not.

Erling Svensen This - I think - is the same anemone as Kåres below. The Metridium senile var. pallidus. We have them exposed and in many different colour variations. Growing only to 3 cm.

Kåre Telnes As you know, I am just a happy amateur, and really don't have a clue. Still, I cannot help thinking that these look a bit different. They seem to have far more tentacles than "mine". "Mine" has less than 50 which is correctly less than the 200 pallidus is supposed to have. Do you have any images of a pallidus with this few tentacles?

Erling Svensen What about Diadumene sincta? I do not have so many pictures at my work - so I look when coming home. But the D. sinctra is an anemone that is also quite common in Norway and look quite like Kåres below.

Kåre Telnes I should leave this to the experts, but could not help myself. I googled Diadumene cincta and the juveniles I found images of, had a very different, vase-shaped cylinder and far more tentacles.

Erling Svensen Fine, Kåre. Looke at the 3 last images.

Erling Svensen Have seen Bernard Picton Habitas pages? http://www.habitas.org.uk/marinelife/photo.asp?item=diacin

Erling Svensen I have big problems to identify sea anemones from Norway. Bernard said he would like a picture down on the disk, one from the side, and one after I have touched it. Here is one that I have done just like that. Any one that will try to name it? It is aprox. 2,5 cm high, and the grow in colonies. From Egersund harbour, 5 meter of sea water.

Estefania Rodriguez uhmmm, beautiful pictures...regrettably I know nothing without looking inside them...Sorry!

Erling Svensen Just like the surgeon people..... ;-)

Andy Horton The spotted column is confusing.

Andy Horton If it is not spotty I think it is Diadumene cincta.

Estefania Rodriguez In the column it has tubercles, some Sagartiogeton species have them...

Andy Horton Tubercles would rule out D cincta, but the poke response in the first picture is typical of D cincta.

Andy Horton Tentacles are like Sagartiogeton undatus.

Andy Horton Based on the Chris Wood sea anemone book I would go on Sagartiogeton laceratus. I do not know this sea anemone though.

Andy Horton https://www.google.co.uk/search?q=Sagartiogeton+laceratus&hl=en&safe=off&prmd=imvns&source=lnms&tbm=isch&ei=G2JfT-2wOOaW0QXH95nkAw&sa=X&oi=mode_link&ct=mode&cd=2&ved=0CA4Q_AUoAQ&biw=1024&bih=606

Erling Svensen Yes, I feel that this is correct. Thanks

Darryl Mayer It would help with ID's if the pictures were larger. I run a notebook and the screen isn't big to begin with and these pictures all lumped together makes them even smaller to the extent I cannot make out any detail.

Erling Svensen If you download the pictures to your own computer you can look closer....

Bernard Picton I agree with most of the comments so far, ie. not sure what this could be!! Erling, did you photograph other individuals or are they all very similar.

Paula Lightfoot Here is its face (I picked it up and moved it to stop it looking down a hole!) - it's a bit blurry but you can see there are no V-shaped markings, which is why I thought maybe Aeolidiella glauca. It was about 3-4cm long.

Andy Horton Who's eating who?

Paula Lightfoot The slug is eating the anemones. On Arran we saw anemones eating jellyfish, gradually pulling them down by their tentacles!! Even a tug of war between several anemones over the same jellyfish!

Peter H van Bragt Hello Paula, for sure A. glauca. It's known to eat a variety of anemones: Like S. troglodytes and Diadumene cincta in Dutch waters. The latter one gives a nice reddish hue in this nudibranch. This seems to be Sagartia elegans? cheers Peter H van Bragt

Paula Lightfoot Thank you Peter ! I thought the anemones were Urticina felina, dahlia anemones, they just don't have as much debris stuck to the columns as they usually do. I saw a couple of Sagartia elegans at this site, but lots and lots of dahlias.