Huge flatworm

[melev]

A DFWMAS member mentioned a beast she found in her tank a couple of weeks ago. Well, it reappeared again last week, and she captured it and left it on my front doorstep for a few images.

It is a very large, and most likely predatory, flatworm. I've seen images of similar ones that will eat an entire cowrie, leaving behind the empty shell. Their pattern makes it possible for them to blend in when on the mantle of a clam, staying unseen as they devour the clam itself.

The underside - almost looks like rows of eggs to me.

 

[Dubbin1]

There is a post on CORA's forum here on RC with the same thing. http://www.reefcentral.com/forums/showthread.php?s=&threadid=907863

 

[chocolateblnt]

yuck!

 

[melev]

Dwayne, thanks for that link to the other thread.

 

[Dubbin1]

<a href=showthread.php?s=&postid=7956118#post7956118 target=_blank>Originally posted</a> by melev
Dwayne, thanks for that link to the other thread.

No problem Marc. I find it amazing that these two strange looking creatures popped up within a couple days of each other.

 

[LeslieH]

It's not surprising that reefers get the same flatworm or same type of crabs over & over again since you all buy the same basic kind of live rock. Many animals have distinct preferences in habitat, for mud or silt, or coral, or rock, and then for micro-habitats like a burrow in limestone rock or only in shale crevices.

The "eggs" are a couple of things, Mark. The branched central structure is the pharynx while the rows off to the sides look like eggs coming off the oviducts. the pharynx in flatworm is highly branched - in fact that's where the name comes from. Poly = many and clade = branch.

This particular species - or maybe several species with the same general color pattern - is definitely a mollusc predator. Unfortunately no one seems to know what it is. If people would send me live animals I can preserve them for study & get them to some specialists for identification.

 

[melev]

Well, I still have these guys alive in a bowl on my counter, although they aren't too happy after several days of cool, stagnant water. Shipping it in a thermos wouldn't be tough, but the weather is insanely hot right now. Let me know if you really want it.

 

[melev]

Okay, I just checked on it. What is left really doesn't seem to be all that healthy, so perhaps it isn't worth the postage to ship it. I refilled the bowl with new tank water, but...

 

[reefshadow]

Wow, that thing is awesome! Thanks for the pics!

 

[Travis L. Stevens]

I've seen those buggers before. I'm glad that you got them out of your tank. They can be quite voracious. Hopefully you get a chance to preserve it and send it to LeslieH

After all, if it looks like it's on its way out, then you might as well preserve it now and let her do what she can with it

 

[charlesjordanjr]

How would you go about preserving it?
-Chuck

 

[LeslieH]

Marc - I'll pass on your specimen, thanks. I'm sure more will pop up.

Chuck -- Polyclad specialists need good color pictures and intact, carefully fixed flat specimen. Normally when these things are put into formalin or alcohol they contort or tear themseles into pieces. You can't just throw them into alcohol. The ideal way to fix them is...
- pour enough formalin (made with 1 part formaldehyde & 9 parts seawater) into a small dish to measure 1-2 cm deep
- put into a freezer until solid
- before fixing the animal, pour just enough ice-cold formalin or sea water onto the frozen formalin to slightly melt the surface
- gently get the animal onto a piece of paper strong enough to hold together when wet; you can use a small paintbrush, a pipette, or float the paper under the animal to manipulate it
- put the paper onto the frozen formalin
- if the animal moves or starts to curl gently pat it with paintbrush to keep it flat
- it takes less than a minute for the animal to stop moving
- cover the dish, let the formalin thaw, & leave the animal in the formalin for 24 hours
- drain off the formalin, gently rinse with fresh water, put into 70% ethyl alcohol
- You now have a properly preserved flat flatworm

An alternative method I use in the field when there's no ice around is to let the animal crawl between 2 stacked glass dishes which keeps it flat, then flood the bottom dish with formalin

If there's more than one specimen or torn-off pieces it should be preserved in 95-100% ethyl alcohol for DNA analysis.

Formaldehyde is embalming fluid - nasty stuff - and needs to be handled with care. OSHA health & safety rules require the use of goggles, gloves, & a fume hood or ventilating system when working with it.

 

[hot4teacher]

<a href=showthread.php?s=&postid=7956129#post7956129 target=_blank>Originally posted</a> by Dubbin1
No problem Marc. I find it amazing that these two strange looking creatures popped up within a couple days of each other.

I find it no surprise as they have 'discovered' the new planets. Perhaps they've have become aligned for this phenomena to happen.

Dana

 

[kcooley]

i found one of these today while moving my tank. it was about 3", the size of a bandaid. Has anybody else gotten more info on them since 2006?