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Sagartia troglodytes

(Price in Johnston, 1847)

Andy Horton An example of Sagartia troglodytes from Worthing, Sussex.

Message posted on NE Atlantic Cnidaria on 27 Sep 2012
David Fenwick Snr Can someone help me identify this one please, was just below low spring, at Carnsew Pool, Hayle, Cornwall.

Andy Horton I would say Sagartia species.

Marco Faasse I would say Sagartia troglodytes. B-shaped marks at the base of tentacles not present in S. elegans. S. ornata cannot be ruled out completely.

David Fenwick Snr Thank you both, give me something to go on.

Andy Horton Location: http://maps.google.co.uk/maps?hl=en&safe=off&q=carnsew+pool+hayle&um=1&ie=UTF-8&hq=&hnear=0x486addb23da84f9b:0x486addb235d913a1,Carnsew+Pool&gl=uk&ei=Db2AT8e1E6n80QX8i7jwBg&sa=X&oi=geocode_result&ct=title&resnum=1&ved=0CCIQ8gEwAA

Andy Horton http://www.hayleharbour.com/harbour-history.htm for an image of the location. It looks good for Sagartia troglodytes

David Fenwick Snr Yes you've got the location, it's a saline lagoon, the tide comes in and out through two tunnels, low water today was 2 1/2 hours later than normal so I was able to go rockpooling twice on two of the lowest tides of the year. The lagoon is where I found more than two dozen Devonshire cup corals last week, quite unusual finding them on the bottom of rocks overlying silt and mud. Images on the following page - http://www.aphotomarine.com/coral_caryophyllia_smithii_devonshire_cup_estuarine.html

David Fenwick Snr Andy, just uploaded a couple images of Carnsew Pool itself that I took today, to the page above.

Andy Horton David F: the page above does not seem to link directly. Cereus is noted from Carsew Pool (previous ID query).

David Fenwick Snr Andy. What do you mean ''link directly'' I copied and pasted the url from my browser on opening the page myself so it should work perfectly well. It does for me.

David Kipling Link works for me too David.

Andy Horton I links to cup coral pics but not to Carnsew Pool pics. Previous message and I was up late, only because I could not sleep because of a lurgy and I was tired etc.

David Fenwick Snr No problems Andy, hope you feel better soon.

Message posted on NE Atlantic Cnidaria on 07 Apr 2012
Erling Svensen Pictures from yesterday. This anemone lives very, very exposed, always very shallow (the upper 3 meters), and grows only to 1 cm in diameter. Any suggestions?

Steve McWilliam Can people post locations with pictures please ??

Erling Svensen Norway, South West coast - look at map.

Erling Svensen Dawn, this one is not S. elegans. They are always the same in many locations, very shallow, and very exposed. I add a picture of S. elegans from the same location. They look very different from this one. Also this unknown one has the same colours and do not have the variations as elegans have.

Peter H van Bragt Possibly Cereus pedunculatus!

Erling Svensen The C. pedunculatus has more than 200 tentacles, this one have less than 100. So??? And I never see it bigger than 1 cm - disc diameter.

Chris Wood Certainly a Sagartid anemone of some sort, but not one I recognise from the UK. The closest thing would be Sagartia troglodytes on appearance alone but the habitat is wrong - though it must have got the troglodytes name from some where so perhaps it can occur in shallow surgy and cave habitats as well as in areas with sediment, which is where we usually find it.

Chris Wood Of course the number of tentacles in a small specimen can be misleading as they can add rows as the grow. Mind you it doesn't look like Cereus as we see it either and again the habitat is all worng.

Marco Faasse I don't know what species this is. But bear in mind that: Sagartia ornata is a small Sagartia species (base max 15 mm) with much less variable colours than S. troglodytes and S elegans, usually shades of green or brown, and able to withstand much more lowering of salinity than either of the other Sagartias. We find it here in the intertidal zone and brackish waters of relatively high salinity. Can there be freshwater influence in the upper 3m (melting snow etc.) at Egersund, Erling Svensen? In contrast to both other Sagartias S. ornata is a species bearing live young. Escape of young specimens through the mouth would be a confirmation.

Marco Faasse Furthermore, in S. ornata I often see light-coloured vertical lines on the lower column, rising up from the rim of the base and breaking up into a row of dots. I belive in S. elegans the dots are scattered randomly.

Erling Svensen Thanks Marco. But Our exposed localities are not influenced by riverwater or brackish water. The salinity is high. I find this species ONLY in very exposed localities fare out from the harbour at the outermost islands. So - I do not know. I would like to sample some and send - but to whom? The vertical lines could be seen on this specie (Picture), so it could be ornata. But I would like to have this confirmed.

Erling Svensen Chris - could I sample some and send to you?

Erling Svensen One more thing - I NEVER see them bigger than 1 cm across. So I do not have a clue of what I see. Best would be to collect and send to somebody.

Erling Svensen Could this be Kadosactis abyssicola? I have the Danmarks fauna book from 1945 and I have looked in the Distribution of marine, benthic macroorganisms in Norway. This is the only one that I feel it could be?

Chris Wood Erling. I am afraid I am not a taxonomist and wouldn't have the facilities to deal with a sample. Sorry.

Message posted on Seasearch Identifications on 15 Jul 2013
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.

Message posted on NE Atlantic Cnidaria on 24 Sep 2013
Erling Svensen One more from the dive today. Very, very exposed (first dive exposed for more than 4 months) on a rock-wall, only the North Sea between me and UK. There were many, many tine anemones from 3 meter to 5 meters deep. Only 1 cm across. I have a feeling that this is Anthopleura thallia. Agree?

Meg Daly I can't see the acrorhagi or column in this view. The oral disc pattern and tentacles are very "Anthopleura-y" to me, though.

Marco Faasse The black an white B-shaped marks near the base of the tentacles are typical of Sagartia troglodytes. The habitat is not typical for this soft substrate species though. That being said, this species does occur on rock in somewhat exposed areas in some numbers, but does not grow as large as usual there.

Bernard Picton I think this is what I'm calling Sagartia ornata. I saw them at Egersund in just a few metres when I visited you Erling.

Erling Svensen Well, I can not agree in this one, Bernard. This one growd only in the most exposed places, shallow, and It do not looks like the one I call S. ornata. I will find some more pictures....

Marco Faasse I have never been able to find S. ornata sublittorally, except in brackish water. It's a viviparous species, it's not a rare event to see them produce young, but I've never seen this in Sagartias with the B-marks.

Marco Faasse After looking at some of my photos I must correct my statement about the absence of B-marks in S. ornata. So it seems not impossible to me that this is S. ornata in spite of the habitat being unusual for this species as well.

Message posted on NE Atlantic Cnidaria on 14 Mar 2012
Erling Svensen Looking on my unidentifies pictures. Here there are 3 unidentified ones. All of them are small - only 2 (maximum) wide and 2 cm high. All pictures is from very exposed coast - on rock. When I say very exsposed - I really meen exposed. The waves can grow to 10 - 15 meters high, and the anemones on the pictures are only from 2 - 5 meter of seawater. The lowest picture to the left - I belive this one is the Sagartia elegans. The middel one looks like the Actinothoe sphyrodeta - but this one have never been seen in Norway (but one time must be the first....). I hope you can make comments and may be help?

Andy Horton Are the rocks buried and the disc protruding? With a long column wedged in between the rocks? Or are the anemones on bare rock exposed to the waves? Actinothoe is lightly adherent and can be peeled off easily. This is doubtful on wave battered shores?

Erling Svensen Hi Andy. The anemones are on the rock itself, not burried. I can not say if there are cracks in the rock, but it looks for me like they sit on the rock itself.

Andy Horton If you poke them lightly do they emit acontia? Any chance of a column picture?

Erling Svensen No, sorry. I will be better to do so....

Andy Horton This makes it difficult. I know what they look like, but the choice does not sit on bare rocks. What is the substrate and incline? Are they on a flat area of sea bed or on a slope? Is there sand or gravel on the beach during the quiet season. What time of year, during the storm season or in summer?

Erling Svensen They are on a slope, like a wall. There are no sand ore gravel as this is very exposed. I have not dived this locality since October last year as the waves have been to hard for 5 months now. Most of pictures from this locality is from summertime.

Andy Horton They are a perfect likeness for Sagartia troglodytes, but the habitat is completely wrong. This anemone will appear in calm weather in summertime, but it as a species found on flat shores where is found buried in sand/gravel but fastened to rocks underneath. Where there holes in bare rock Sagartia elegans is usually found. Bigger pictures may help.

Message posted on NE Atlantic Cnidaria on 13 Mar 2012
Erling Svensen This tiny anemone, only 1 cm high, from the night dive yesterday. Could it be Sagartia ornata? Bottom soft with dead mussels, 12 meters deep.

Andy Horton It is hard to ID anemones. It is wedged between the shells with a long column? This would be like Sagartia. It does not show the variety of colour pattern I have seen in Sagartia troglodytes, so I think it is a different species with Sagartia ornata being favourite.

Erling Svensen Thanks. I have a feeling also for S. ornata. Lets wait for Bernard and hope he agree!

Estefania Rodriguez Bernard, at the end you know more about identifying living anemones from pictures...I can only confirm ID if I have the "beast"...

Bernard Picton I'm on the road at the moment, will look at this next week.

Bernard Picton Faani, do you have any resources for showing people how the tentacle arrangement is described? Perhaps a photo with the primary, secondary etc. tentacles labelled?

Cynthia D. Trowbridge May I ask about what type of camera you use? Sorry for the technical question but you photo is so clear! Thanks!

Bernard Picton Don't ask Cynthia! It's the flashguns (strobes) and lighting too. I wish I could see what it was he does differently to me!

Bernard Picton Erling Svensen, the disc pattern is most like Sagartiogeton laceratus in my opinion. If you are photographing anemones for ID it's important to be able to see the column too, and something straight down (not artistic) on the disc for seeing the exact tentacle arrangement. I appreciate that this is small, and those things aren't always possible. The other thing to do is give it a poke so it closes; that will show the top of the column usually, whether the tentacles are taken right in, and sometimes white threads, acontia, will be expelled. These are all important clues for ID of unknowns.

Erling Svensen About the camera and phototechnique: I use (still) the Nikon D-300 in a Subal housing with two flashes, one on each side. The aperature is important. Here I used aperature 32 that gives me maximum dept of field. If the picture is to sharp I can run it in Photoshop and blure it a litle bit ;-). I said still - now I am waiting for the Nikon D-800 that will give 36 Megapixel :-)

Erling Svensen Thank you Bernard fort the descripsion about how to take pictures that gives maximum possibility for identification. I will remember. For us "non biologists" it is a good help to learn how to photograph so that all of you specialist can see what you need for identification.

Andy Horton Sgartiogeton laceratus http://www.marlin.ac.uk/speciesinformation.php?speciesID=4288 I always (uo to now) forget this species because I have never seen one.

Andy Horton Can anybody suggest a common name for this species? http://www.naturalengland.org.uk/ourwork/conservation/biodiversity/englands/nameaspecies2011/Sagartiogetonlaceratus.aspx

Bernard Picton I agree with Bill Rudman re. common names. This group is intended for multiple nationalities. http://www.seaslugforum.net/find/common

Message posted on NE Atlantic Cnidaria on 07 Feb 2012
Andy Horton Sea Anemones (Aquarium Study)

Andy Horton 8 sea anemones of 6 species (some not so easy to spot and ID?)

David Wilson I can only see 5. Dahlia, beadlet, gem, possibly Sargartia elegans and maybe Caliactus parasitica. The other one is well hidden.

Andy Horton The purple one and the one next (right) to it is Sagartia troglodytes. The one hard to see is under the Prickly Cockle shell. I am not sure if it can be seen even if the picture is enlarged? I'll try it out.

Andy Horton Callaiactis parasitica is not there. The one to the left of the green Beadlet is not identified yet. I know what they are.

Andy Horton The one under the cockle shell is only possible to guess as it is not clear even when blown up. This is a scanned in transparency and it was scanned in a long time ago. I might be able to provide a better resolution picture one day. But the standard of photographs are so good now, I am not sure I will be able to match modern quality?

Andy Rapson The unidentified one next to the green beadlet, might it be Sagartiogeton undatus ?

Andy Horton Yep. The brown unidentified one can be seen clearly (but not clearly enough) in the cover photograph at the top of the page. And inserting a cover photograph was the whole point. I may change this one for a better photograph later.

Cathal McNaughton Found this earlier this evening, it appears to be a juvenile Dahlia anemone (Urticina felina), almost colourless and transparent. I couldnt quite get the focused shot I wanted, this being the best one I managed. Very small, a 5p coin would almost completely hide this.

Cathal McNaughton Just noticed there is a smaller one below it.

Andy Horton Looks more like Sagartia troglodytes

Andy Horton If you poke Sagartia elegans it should discharge acontia. Sagartia troglodytes probably won't. Classic Sagartia troglodytes colouring though.

Cathal McNaughton Thanks for this Andy and Dawn. Those are both new species to me, the 2 youve mentioned. I really thought this showed marking very similar to U felina and that it was a juvenile of that species. I was photographing mature U felina a few minutes before I found this tiny anemone.

Cathal McNaughton I think I'll have to go back tonight, find one of these and give it a poke to see what happens.

Andy Horton If you want to dig them up you would need at least a garden trowel.

Andy Horton http://www.glaucus.org.uk/S-troglo.htm

Richard Girdler

David Kipling Tentacle?

Richard Girdler Quite a bit longer than the other tenticles

Rob Spray Is it a defensive acontia - a really stingy tentacle?

Andy Horton It is an ordinary tentacle enlarging itself in Sagartia troglodytes. Best picture I have seen of this. http://www.glaucus.org.uk/S-troglo2.htm They could be called "catch tentacles".

Andy Horton 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. Pic to be included 2) American research in different species of sea anemone attempted to prove that these 'catch tentacles' were used in territorial warfare between species of the same anemone to ensure spacing. In the wild Sagartia troglodytes will be found at least an anemones width away from other anemones. Aquarium experiments to try and induce the 'catch tentacles' to appear - not a predictable task - but I have managed this by introducing live Artemia brine shrimp into the aquaria and this stimulated the 'catch tentacles' to search the surrounding water for nutrition.

Andy Horton PS: Can I include your picture on the web page with the appropriate credits please?

Richard Girdler Crack on andy :) thanks for that info

Message posted on Seasearch Identifications on 28 Jul 2013
Animalia (Kingdom)
  Cnidaria (Phylum)
    Anthozoa (Class)
      Hexacorallia (Subclass)
        Actiniaria (Order)
          Nyantheae (Suborder)
            Thenaria (Infraorder)
              Acontiaria (Superfamily)
                Sagartiidae (Family)
                  Sagartia (Genus)
                    Sagartia troglodytes (Species)
Associated Species