Green Tentacle

[bhanson]

A couple nights ago I noticed a solid green tentacle about 1 -2 mm thick and over 1 foot long coming out of one of my rocks. It has a forked tounge like appendage at the end. I have seen it retract back into a small hole in the rock and come back out again into the water column. I guess it belongs to some kind of worm but what kind.

I will try to get a picture up tonight.

Thanks

 

[John_Brandt]

It's probably a ribbon worm (Nemertea). Can you describe the forked appendage in detail please?

 

[bhanson]

Yes the forked appendage is at the end of the tentacle/worm. To me it resembles a snakes tounge or like a two pronged pitchfork about 1/2 inch between the two "forks".

Thanks

 

[bhanson]

I looked at some pictures of the Ribbon Worms (Nemerteans) and I did not see anything that resembled what I saw.

It behaves much like a polychaete of the Family Spionidae the way it uses its tentacle to pull in debris. Only this tentacle is enormous.

 

[John_Brandt]

I think I'll still stick with ribbon worm until you post a good photo. The forked appendage seems out of place however.


Here's one...

Photo by Tracy Meintjies

 

[bhanson]

I'll try to get a pic tonight, but that photo you posted looks kind of like it. Thanks for your help

 

[John_Brandt]

It behaves much like a polychaete of the Family Spionidae the way it uses its tentacle to pull in debris. Only this tentacle is enormous.

Enormous tentacle? I thought you said it had a "fork", with a half-inch space between the ends. I'm getting confused.

 

[bhanson]

Yeah at the end of the tentacle is the fork. Looks like this:

----------------------------C

Its green and in comes in and out of a small hole in the rock.

 

[John_Brandt]

Have you seen the body of the worm that the tentacle is attached to?

 

[bhanson]

I have not seen the body of the worm I will look again tonight and I will try to get a picture. Thanks for your help.

 

[John_Brandt]

So the part that is a foot long is a tentacle, not the body of the worm?

 

[bhanson]

Yes that is correct it is the tentacle. I have yet to see the body.

 

[John_Brandt]

Standing by for the photo....

 

[bhanson]

Still trying to get a pic but no luck the thing retracts real fast back into its rock as soon as light hits it. Oh well, maybe tonight.....

 

[spoonhandler]

I have a similar creature. The picture of the ribbon worm above looks like the same thing to me, with one of the paired appendages curled over.

I have posted my pic below - you can see the anchor-shaped end. I've watched this creature a lot - it extends from a hole in the LR, can stretch out more than 3 inches at least whilst the anchor part can flatten and expand to almost an inch across. It seems to adhere to the rock, collecting small particles which are shipped back to the hole along the stalk. They aren't swallowed - the stalk forms a tube that is open along one side and the bolus is somehow transported along the stalk (cilia I think - no obvious sign of peristaltic motion).

I'd love to know what it is - at the moment we know as the Green Thing.

This could also go in the Hitchiker's Archive if the photo is considered good enough.

 

[bhanson]

Yep, thats it!!! I have tried for a week to get a good picture of it. Mine stretches out almost a foot from its hole, I really want to know what it is too.

The ribbon worm does look similar, but that pic is of the worm itself and I believe this thing to be a tentacle of a worm. I have not seen the animal that the "Green Thing" is actually attached to.

 

[John_Brandt]

This is an Echiuran or Tongue worm. Probably Bonellia sp.

 

[spoonhandler]

Excellent! Thank you John - I had no idea where to even begin finding info on this creature. I'm also thrilled to find these are sometimes called 'spoonworms'.

http://biodidac.bio.uottawa.ca/thumbnails/filedet.htm?File_name=Echu004b&File_type=gif
http://www.biologie.uni-osnabrueck.de/speziellezoologie/Hessling/FR-home.html

So, the visible part is referred to as a proboscis or prostomium, rather than a tentacle.

Quote from the second link:

The body consists of a cylindrical trunk which reaches a length of 12 cm. or more, and a preoral lobe or prostomium, shaped like a hemispherical fan when fully extended, which is about half as long as the trunk. The prostomium is ciliated on its ventral surface and its margins are fused at the base, forming a funnel around the mouth. During feeding the prostomium is extended over the surface of the surrounding mud, and particles of detritus are swept along ciliary tracks toward the mouth.

Also, it is a 'she' - the male lives as a parasite in the uterus and is only 1-2mm long.

Most of them are green, it would seem.

The majority of species are of an intense green colour; the pigment, known as bonelline, is a mesopyrrhochlorine, chemically a degradation product of chlorophyll. It is highly toxic to other organisms and may therefore have a protective function; the green tissues are usually rejected by predators. The lytic properties of bonelline solutions toward echinoderm larvae are enhanced by simultaneous exposure to light; it may be, for this reason, that Bonellia, which avoids light and is nocturnal, cannot tolerate appreciable illumination.

What a fascinating creature!

 

[Anonymous]

The taxonomy of these guys is particularly interesting...I was a bit confused on that first link because it basically says that Echiurans were a class in the phylum Annelida. As far as I know there are only 3 classes in Annelida; Polychaeta (marine bristle, fire worms, feather dusters), Oligochaeta (earthworms), and Hirudinea (leeches). It also said they were *unsegmented*, but segmentation is a defining characteristic of all annelids. The second link then says they might be in their own phylum.

 

[John_Brandt]

Brian, if you had more accurately described this creature early in the thread I could have nailed the ID right away.

Yeah, these are unique animals that are worm allies but don't really fall into the classic worm groups. They are closely related to the Sipunculids.


It's not the only taxonomy "problem" out there that is a square peg which just won't fit into a round hole.



Here's what happens when a Royal mammal (Prince Harry) meets a mammal that lays eggs (Spiny Echidna) :wink: