Had a little surprise when the scallops arrived.. a little surprise that had a big meal!
Found him munching (killed) the scallop. Caught him and have him in a little breeder cup in the tank as I am afraid to let him loose until we know what he is. I know so far not to put him where there will be clams!

Can ANYONE identify this creature.. plz.

it is almost translucent.. the shell on top seems to be in two parts and they curve up at the ends.. especally over his face. The red you see in his coloring is only what you see from his stomach contents "Flame Scallop".

Thank you
Beth
 

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Charlesr1958

Experienced Reefer
Hi Beth,

Wow, thats a new one on me and have no clue, and I have seen a LOT of crabs, but nothing like this. Can you also post a frontal view of it? Some of its claw and mouth details may give me a clue as to what family to look into. And fair warning, if it is found out what it is, I am going to be begging you to let me use the photos within my hitch hiker pages...lol

If all else fails, might you post it in Dr. Shimek's forum at marine depot.

Chuck
 
Going to add a few more shots of him/her So hard to get a good shot.. so clear except the two dots and the belly still has the red meat.. and can't see the mouth even when he eats!!
 

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The silver spoon reflected the color back up.. so hard to get a shot of this little guys face.. If I move him to get it.. he topples face first. LOL
Added the one from when he was in the tank.. but sorry bout the blue light on that one.

I have written to places now thru the world looking for an answer.
 

Charlesr1958

Experienced Reefer
Nope, am still at a loss...lol, Am wondering though if the redness of it, given the location and size of the reddness, if its due to crab being a gravid female (eggs), if the red was stomach content, it should not cover that large of an area.

Would you mind if I copied the photos and sent them to biologist for ID?

Chuck
 

Charlesr1958

Experienced Reefer
Okay, I took the liberty of showing your crab to Leslie Harris of the L.A. Natural History Museum and this is her reply:

Quote : "That's a pea crab, family Pinnotheridae, Durckheimia caeca. Their preferred hosts are flame scallops. Pea crabs are commensals that associate with various echinoderms, molluscs, polychaetes, brachiopods, etc. Some are external while many of them are internal living inside their hosts' gill chambers or body cavities. As far as feeding goes there are several different modes for the internal ones. They can be "kleptosites" - stealing the mucus feeding strings of their hosts, feed directly on non-feeding mucus produced by the hosts, or filter plankton/particulates for themselves. They don't damage the hosts by feeding on them. One study on a species that lives inside holothuroids found that even when cut-up chunks of host holothuroid was given to them the crabs didn't eat the meat. Instead they rubbed against it to get mucus. They're pretty much harmless but not completely - they can cause some damage especially to gills or inhibit growth by stealing food away.

It's very unlikely that this crab caused the type of damage the reefs.org poster described. It does appear to be a gravid female and the red is from eggs. I don't know how long an internal obligate commensal like this will survive without a host to occupy. End Quote.

Also, may I include / use your photo(s) within the crab section of my hitch hiker pages? If so, I would need to give you photo credit for them and would need to know the name in which to credit. Thanks.

A Hitch Hikers Guide to the Reefs

Chuck
 
I'm not certain that she is correct. But, we shall see.
I am familar with crabs and egg sacks.. ect. I will try to continue to nurture this creature see if it lives and if the 'stomach' contents eventually change the 'red' to brown or another color.
This creature was definately munching on the meat of the scallop.. we seen this.

Again, I will still continute to look for answers, I will supply those I've contacted with her theory of the pea crab and do more checking into it myself.
I have went to google images and checked pea crabs and I have found nothing that resembles this little creature in the slightest.
The little one I have has those pearly wheel designs and the lifted ridges at all the egdes. The pea crabs I'm seeing in the photo's the upper leg sections are way larger than the lower where this little one has the same size leg from lower to upper.. Just to many differences and not anything really alike other than it was found in the Flame Scallop.. I will still look, but even more now.. I believe she is mistaken.

As for the Photo..
Beth LeBlanc

And you are more than welcome to use the pictures. I will still try to get you a better shot of him/her .. front view in brighter light.

I will keep you posted.

Beth
 

Charlesr1958

Experienced Reefer
Thanks Beth, I also heard back from Dr. Ron Shimek and I quote yet again..lol

" Probably one of the many pinnotherid crabs (Family Pinnotheridae), but Leslie may know differently. I have no references for the tropical ones. Pinnotherids are very abundant in moderate to large clams everywhere. Although called commensals, really all the term commensal means is that it lives on a host and we don't know what it does. :)... They are more than likely ectoparasites. Pinnotherids live in the mantle cavity of the clam (and that is outdoors, of course, hence the "ecto.." in the parasite). Those that have been studied seem to eat (steal) the food collected on the clams' gills. Another word for this type of parasitism is kleptophagy (i. e. they steal their food; and the animals are kleptoparasites. They may also simply eat pseudofeces, and real feces, in which case they are "honest" commensals.

In any case, it takes some work to find out what they are doing, and by and large the work has not and probably never will be done. Nobody seems interested in that sort of thing these days.

The females typically stay in the clams, the males are "Roving Romeos" and go from clam to clam to find girl friends. I have attached a couple of images I took in the field of males I saw out "roving."

They may also eat some of the clam's tissues, but that is doubtful - as it doesn't pay for them to kill or injure their host. Their motion in the mantle cavity does seem to cause some minor injury to their host, but it doesn't seem to do more than that.

Generally, there is one or, maybe, two per clam. Some of them get pretty good sized; those in the geoduc (pronounced "gooey duck" = Panope abrupta), of the Pacific NW get up to 3 cm or so in width. Then again, that clam species is the largest in the world outside of the tridacnids, so the crabs are sized to the clam. I have seen a lot of them in much smaller clams, and the crabs can be really "huge" compared to the mantle cavity that they live in. In the smaller clams, they may effectively fill it.
End Quote.

Of course now everytime I see such clams out on the reef, I am going to have to take a much closer look at them...lol

Chuck
 

LeslieH1

Experienced Reefer
Charlesr1958":kry6mgd0 said:
Okay, I took the liberty of showing your crab to Leslie Harris of the L.A. Natural History Museum and this is her reply:
Quote : "That's a pea crab, family Pinnotheridae, Durckheimia caeca. Their preferred hosts are flame scallops. Unquote
Chuck

Durckheimia caeca may not be a rare crab but because of its life inside flame scallops it's not seen or photographed very often. Here's a line drawing of one http://www.bioone.org/perlserv/?request ... -1-116-f03

If you have access to a library or ejournals check out
Journal of Crustacean Biology 2005, vol. 25(1): 116-129 Review of Durckheimia and Xanthasia, with descriptions of two new genera (Decapoda: Brachyura: Pinnotheridae) by Shane T. Ahyong and Peter K. L. Ng2
 
I have been working at new photos of this little thing.
I agree with you about the stomach area vs eggs. I am able to see with the magnified view much better than I can keep a camera in focus to take a shot :( and it still does not seem to be eggs. Alto.. that does make way more sense.
Now.. More info on this little one and more pictures supplied to any of you's that are interested.
When we got the Electric flame scallops we had also had a few other things added to the tank reciently.
So.. it is still possible this little one did not come inside the scallop.
When we got the scallops the shipment had been messed up and they didn't arrive until second day.. the temp in the container had dropped and the scallops were not in good shape. We also had an arrow crab and two red legged hermits. One scallop I was so certain we had lost upfront.. but, I still placed it with the other in the tank with hopes that it would bounce back. Hubby had gotten a nice live rock with all the shrooms and growths on it from our regular supplier about 2 weeks before this shipment.
So, now back to my story. The second scallop looked like maybe it could pull thru and we were watching them closely. The rock had been placed in the community tank by now not that 'that' matters. (Just still wondering.. did he hitch with that) or even with other shipments of rock we'd gotten in the past month or so.
The second scallop was starting to look stronger and had even begun to 'fire'. But, the next day (about 3 days from arrival) went to check on him that next morning and the tissue was torn up and in shreads..
So, he went from looking strong and fireing.. to the shredded condition and 'dead'. This is when we seen the movement inside and found the little white crab. I placed the crab and the dead scallop inside the breeder tank so I could watch closer. He definately was eating the scallop.
I cleaned out the breeder tank, added some rubble, cleaned the scallop and added the shell back in for him to 'hide' in. I placed a tiny bit of the scallop flesh back in with him and he went to town on it.
He/she has no problem eating bits of food that I feed the other fish.

The red dots you seen in the round photo I posted earlier are pieces that had floated around from the scallop meat I had dropped in there moments earlier.
This crab works hard at keeping anything off it's shell and keeps itself very clean.
Very top heavy (face first) when you move it around. Taking the new pictures were difficult.. hubby had to try to lift the little thing's face so it wasn't going face down.
It is not agressive.. seems to plop on it's face.. and lifts the rear two legs up at first. Then when messed with more it just closes in and doesn't move at all. The only time I've seen it use it's pincher is to clean it's shell, picking food and just a couple times trying to get the toothpick off of it's shell when we tried to lift it's face to smile for the camera.

I am going to post the pictures I am taking onto my snapfish site.. so anyone that is wanting to wade thru photo's of him please contact me and I will send you an 'invite' to see the photo's there as I have dozens now trying to get better photos.
I appreciate all the help that is being offered here!!
Thank you all so much.
(edited in--) Please note that this little one is 'not' round or bubble shaped on the top. The picture seems to show it that way.. but, it is flat (almost pressed inward on top) has the 'two' sections separated by that 'spike' down the top center.
Beth.[/img]
 

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LeslieH1

Experienced Reefer
Hi Beth --
It's very clearly a female whose protruding abdomen is full of eggs to the point where the crab plops forward rather than remain upright. Some species are sexually dimorphic in that the females which stay in the host for their entire lives look quite a bit different from the males which are free-swimming. See http://www.imv.uit.no/crustikon/Decapod ... _pisum.htm

Normally pinnotherids don't eat or do much damage to their hosts. As most crabs are opportunistic scavengers it's not surprising that one would eat necrotic flesh from the host or completely scavenge a dead clam. What scientists know about marine invertebrate behavior is pretty slim as it's so hard to study them under natural conditions. With a small commensal like this it's even harder.

Durckheimia caeca is only known from individuals found inside flame scallops. A couple of pictures from other reefers have been posted, and again, the crabs were from flame scallops.
 
I will not list names of who contacted me as I'm not sure of the legality of sharing a personal e-mail..
But I will copy paste the info of what I feel I can share on here..

The little one seems to be doing well still. Still in the holding breeder cup, seems to be eating well.

Thank you all again,
Beth


To: Beth L.
Subject: Re: Can you help identify this crab?


Dear Beth LeBlanc,

Thank you fur your inquiry. On the basis of the pictures provided I can
only give an intelligent guess:

I think the crab is Nursia or Paranursia (both leucosiids). If so, it
will be from somewhere in the Indopacific ocean. Please give me the
details of the page where I can see more pictures and I will try to do
my best to specify my "intelligent guess"

Best wishes

Michael
 
The little crab seems to be doing well as I said. But, with e-mails coming in from across the globe and people putting effort into finding what it is.. What if it should die!! Is there a way I can preserve it so someone could actually study it later if they wanted? I am just a housewife, no special training. Is there a way to get a small preserving conatiner sent to me, do I just toss it in the freezer?
It seems to be well, and I am doing all I know to do.. which is do nothing! Just feed and take care of the tank as usual.


It's shell is smooth to the touch on top. The ridge all the way around the edge is almost perfect with the exception of the front edge over his left eye.. where I am not sure if the pressure from me trying to lift with the toothpick caused the indent or not.

Again thank you all for everything.
 

LeslieH1

Experienced Reefer
If it dies and you see it before something scavenges the body throw it into a container filled with 70% or higher percentage alcohol. Everclear, rubbing alcohol, or a high proof clear liquor like Baccardi 151 white rum are acceptable. Let it sit overnight, drain off the alcohol, then refill the container with fresh alcohol.

I suggest you send your photos & info to Shane Ahyong who is one of the world's top specialists on pinnotherids and lead author of the paper I cited before. His email is s.ahyong(at)niwa.co.nz
 
I've finally gotten the hang of how to photo it a little better.. I snapped pictures like crazy as this little one went across the breeder and back.. so out of the 100 I think I have rear, front, sides covered better. The breeder is getting some algae bloom in it and the little one has some too now.. I have got to clean the breeder container out. The little one made it thru the dish and photos.. so Should pull thru me taking it out and cleaning it's home.
If anyone has the link to the snapfish you are welcome to go back and see the new photos..
If anyone would like the link to the snapfish contact me at eggcrafter(at)ec.rr.com and I will send you an invite to view it.
The bright red has changed more to a light brown in it's belly area.
I've almost forgotten about all my other tank life and so focused on this little one.. LOL poor fish. :)
All is well tho.. and thank you all for trying to help.

I have contacted Shane, Michael, Mr. Ng and a few others that are checking into it and going to look at the snapfish site to get a better look.
I will keep you posted.

Beth
 

LeslieH1

Experienced Reefer
Hi Beth -- did you ever get a reply? I'm curious to know what it is and what the experts thought about the behavior.
 
Hello again Leslie,

Well.. to answer your question..
Not exactly!

I will include some of the e-mails I've gotten but not flood you with all.
There was even a man in New Zealand that wanted to have it to study if I did not want to keep it.

Once the crab was separated and only fed dark food the red in the belly changed to brown. So, I take it .. not eggs.
He/she is growing and getting whiter. Nothing else has changed other than a bit less timid.
Still have not released it into the normal tank but, we are on the verge of it as I am getting tired of the breeder tank in there and the troubles of keeping it algae free.
Since I am not sure what it is or what damage it possibly can do even tho I have no clam type's in there at the moment..doesn't mean I won't want to add some and then I will be wondering.. will the crab kill it.
So.. we are still tossed.. finding it in the rocks would be next to impossible once I release it.
Husband wants to just toss it to be on the safe side. I'm wanting to just release it.. LOL So.. the Breeder tank it is.

I was just thinking about the forum today and going to post a note of 'still not sure'.
Thank you for thinkin about us.

Beth

Dear Beth LeBlanc,

Thank you fur your inquiry. On the basis of the pictures provided I can
only give an intelligent guess:

I think the crab is Nursia or Paranursia (both leucosiids). If so, it
will be from somewhere in the Indopacific ocean. Please give me the
details of the page where I can see more pictures and I will try to do
my best to specify my "intelligent guess"

Best wishes

Michael Tuerkay

Hi Beth,

Your crab is a species of Durckheimia, but I'll need to see more images before I can give a more complete identification. It's a very interesting genus of pea crabs which uniquely has the very thin longitudinal crest on the carapace. They are very rarely seen (though probably common) and usually live inside species of Limidae - so if you had a flame scallop or file shell in your tank, it probably came from there. Do you know what host it came from?

If you are not planning to keep it, I would be very interested to study the specimen since these are not often seen. In any case, it would be very good if you could take some good photo's - I'm certainly interested to see the other images you have on snapfish. Attached is a recent paper figuring the species of Durckheimia as well as species that live inside giant clams.

Let me know if you need any further help.

Cheers,

Shane.

Hi Beth LeBlanc,
I think it's probably a pinnotherid, too, but the photographs are not
particularly helpful for identification. There are other commensals,
particularly a few portunids from sea cucumbers and sea anemones, but the
fifth, or last, leg is not paddle-shaped as in most of the portunids. Did
it just occur in your tank or do you have other inverts in the tank? Do you
have clams or other bivalves in the system? Pinnotherids are often found in
mussels and oysters. I've got at least two recipes for them somewhere, and
I've even eaten them. They can be eaten whole (after cooking) because their
shell is soft. :) All pinnotherids are commensals and I suspect it came
in inside of something. I agree with Dr. Ron Shimek's comments.

I don't think it's a leucosid, but the photos are not of high enough
quality to tell. Is it a tropical or temperate tank? Can you get a better
picture of the dorsal or top of the crab?
Jeff

Hi Beth,



I finally received a response from our aquarists about the crab images you sent us. We have also asked for some feedback from another member of our staff but haven’t heard anything back yet.



Here is the response I have received so far.



Hi Dawn,

I quickly looked at it and my first comment is that I don’t know what it is! It sounds like a tropical crab and not knowing the history but reading between the lines makes me think this person has it in a tropical saltwater aquarium? Lee also quickly looked at it and had no idea but he said he isn’t an expert on tropical crabs. It sort of looks like small pea crabs that we have around here that often live inside clams but if it ate this person’s scallop then maybe not that type of crab? The carapace shape looks different and almost makes me think it could be a newly settled juvenile of whatever species it is? I will send images to Tak who has more experience with tropical species to see if he can figure it out. If this person is really eager to identify it they could try sending the images to a friend and colleague from the University of Washington Dr. Greg Jensen who specializes in crustaceans?

Regards,

Dawn Bassett

Manager, Content and Information Resources

Robin Best Library

Vancouver Aquarium

PO Box 3232 Vancouver, BC

V6B 3X8

604.659.3404



Hi again Beth,

One of our other animal people sent along the following.

I think I found it.

It's Durckheimia caeca .

I don't know its common name but this species seems known lives in flame scallop.

I could not find photo on the net but found it on my book.


Tak

Cheers!



Hi
it looks like Durckheimia caeca- a female with eggs. A very unusual kind
of pea crab, as most have a smoothly rounded carapace.
Greg
 

LeslieH1

Experienced Reefer
thanks Beth. If Shane says its a Durckheimia that's good enough for me. He is one of the world experts on the group and is certainly more likely to recognize it than anyone else who answered your emails. I see Greg & one other went with D. caeca.

Eggs change color as they develop so the change from red to brown probably means they're closer to hatching.

Cheers, Leslie
 
Went from red to brown that first few days then were gone totally.
That huge 'lump' of red went away in less than two days after it was taken from the scallop.

All the names mentioned that e-mailed me that I copy pasted were all phd's of somesort's
.. 'all' crab experts from around the globe.

So.. do you or anyone else feel it is safe to release it in the general tank?

Thanks
Beth
 

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